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  • 101
    Electronic Resource
    Electronic Resource
    Two-Dimensional Gas Chromatography. Concepts, Instrumentation, and Applications - Part 2: Comprehensive Two-Dimensional Gas Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 167-181 
    Details
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional GC ; GC×GC ; orthogonal chromatography ; GC/MS ; group type separations ; PCBs ; petroleum ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The writer of this review published in 1978 a three-part article on two-dimensional gas chromatography in the first three issues of this journal [1]. The review was written at a time when capillary column GC was still in its infancy. Commercial columns were (essentially) unavailable and sample introduction into capillary columns was done exclusively in the split mode. Two-dimensional separations were explored in only a few laboratories. The limitations of capillary column technology made this exercise rather difficult. The introduction of fused silica capillary columns in the early eighties drastically changed the landscape in which gas chromatography was practiced. It took the chromatographic community just a few years to convert from packed columns to capillary columns. Instrumentation and accessories specifically designed for capillary column use came onto the market. This writer had great hopes that the revolution in capillary column GC would be mirrored in the development of instrumentation for Two-Dimensional Gas Chromatography. This never materialized. On the contrary, tentative steps taken by a few manufacturers and suppliers of chromatographic equipment fizzled out. It was perhaps the introduction of relatively inexpensive and user friendly GC/MS instrumentation, in combination with nearly indestructible fused silica capillary columns that took away the incentive to develop commercially viable Two-Dimensional Gas Chromatography. Much of the thinking went like this: why insist on good chromatography if mass spectrometry can do the job without the need of complete separation. Some progress in the further development of conventional Two-Dimensional Gas Chromatography has certainly been made over the last 20 years but there has not been a great deal of excitement. Applications have also been relatively sparse and they are limited to just a few areas. Science does not remain static and chromatography is no exception. Progress in gas chromatography is driven by new technology and ideas. Substantial improvements in two-dimensional GC were not forthcoming until Phillips and his research group introduced and implemented an entirely new form of Two-Dimensional Gas Chromatography, called comprehensive GC×GC. This breakthrough occurred only in 1991 [2]. It does take some time before scientists change attitudes and habits. There is always a time lag between the introduction of new technology and its general acceptance. The public's attitude toward comprehensive Two-Dimensional Gas Chromatography is probably no exception. The number of scientists who are actively pursuing this new branch of gas chromatography is still very small. It is often a single individual who carries the torch. J.B. Phillips' name is synonymous with comprehensive Two-Dimensional Gas Chromatography. He is not only its inventor and proponent but his fertile mind has initiated research in other related areas. Sadly, he passed aware shortly before this review was written. This contribution is dedicated to his memory.
    Additional Material: 9 Ill.
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  • 102
    Electronic Resource
    Electronic Resource
    Jet-Cooled Thermal Modulator for Comprehensive Multidimensional Gas Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 202-204 
    Details
    ISSN: 0935-6304
    Keywords: GC×GC ; comprehensive two-dimensional GC ; thermal modulation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A jet of cool gas is used to locally cool a section of modulator tube in the presence of the stirred oven bath of a GC×GC instrument. Local cooling decouples the temperature of the modulator tube from that of the first dimension column, which was 100 meters long. Overall resolution of the GC×GC experiment was improved as a result. Another consequence of the jet-cooled thermal modulation structure is the elimination of moving parts in the GC oven. By pulsing cold and hot jets of gas onto a modulator tube with solenoid valves, two stage thermal modulation can be obtained without the complexity of moving parts in the vicinity of the capillary columns.
    Additional Material: 1 Ill.
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  • 103
    Electronic Resource
    Electronic Resource
    GC3: Comprehensive Three-Dimensional Gas Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 205-207 
    Details
    ISSN: 0935-6304
    Keywords: GC×GC ; thermal modulation ; comprehensive three-dimensional GC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Comprehensive three-dimensional gas chromatography (GC3) is demonstrated using modified GC×GC apparatus. A new thermal modulation scheme employing a single moving heater to operate two thermal modulators is introduced. Considerations of the bandwidth/resolution tradeoff of GC3 show that high-speed tertiary columns would make GC3 practical, with modest loss of underlying GC×GC peak capacity.
    Additional Material: 3 Ill.
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  • 104
    Electronic Resource
    Electronic Resource
    Application of Comprehensive Two-Dimensional Gas Chromatography (GC×GC) to the Qualitative Analysis of Essential Oils (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 208-214 
    Details
    ISSN: 0935-6304
    Keywords: Spearmint ; peppermint ; GC×GC ; essential oils ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This paper investigates the separation of moderately complex samples by comprehensive two-dimensional gas chromatography (GC×GC). The analysis of peppermint (Mentha piperita) and spearmint (Mentha spicata) essential oil components, including acetates, alcohols, furans, ketones, sesquiterpenes, and terpenes, was achieved by one-dimensional gas chromatography with quadrupole mass spectrometry detection (GC/MSD) and GC×GC with flame ionization detection. Peppermint essential oil was found to contain 89 identifiable peaks by GC×GC compared to 30 peaks in the GC/MSD chromatogram. Likewise, 68 peaks were found in the GC×GC chromatogram of spearmint (compared to 28 in GC/MSD). Plots of the first dimension versus second dimension retention times provided a fingerprint of the two essential oils, which revealed 52 similar compounds between the two essential oils as opposed to 18 matches by 1D GC.
    Additional Material: 6 Ill.
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  • 105
    Electronic Resource
    Electronic Resource
    Pressure-Tunable Dual-Column Ensembles for High-Speed GC and GC/MS (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 225-234 
    Details
    ISSN: 0935-6304
    Keywords: Tunable column ensembles ; high speed GC ; comprehensive two-dimensional GC ; time of flight ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A series-coupled ensemble of two capillary GC columns of different selectivity with an adjustable pressure at the column junction point is used to obtain tunable selectivity for high-speed GC and GC/TOFMS. An electronic pressure controller with a 0.1-psi step size is used to obtain numerous computer-selected unique selectivities. System configurations for conventional, atmospheric-pressure outlet operation with flame ionization detection and for vacuum-outlet operation with photoionization detection are described for GC-only experiments. Polydimethylsiloxane is used as the non-polar column and polyethylene glycol (atmospheric outlet) or triflouropropylpolysiloxane (vacuum outlet) is used as the polar column. For GC/TOFMS experiments, 5% phenyl polydimethylsiloxane was used as the non-polar column, and polyethylene glycol was used as the polar column. The time-of-flight mass spectrometer can acquire up to 500 complete mass spectra per second. Since spectral continuity is achieved across the entire chromatographic peak profile, severely overlapping peaks can be spectrally deconvoluted for high-speed characterization of completely unknown mixtures. For mixture components with significantly different fragmentation patterns, spectral deconvolution can be achieved for chromatographic peak separations of as little as 6.0 ms. This can result is very large peak capacity for time compressed (not completely resolved) chromatograms. The use of columns with tunable selectivity allows for precise peak-position control, which can result in more efficient utilization of available peak capacity and thus further time compression of chromatograms. The limits of tunability and deconvolution are tested for near co-elutions of different classes of hydrocarbon compounds as well as for more multi-functional mixtures.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 106
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of new nootropic acylprolyldipeptide and its penetration across the blood-brain barrier after oral administration (2000)
    Springer
    Bulletin of experimental biology and medicine 129 (2000), S. 359-361 
    Details
    ISSN: 1573-8221
    Keywords: acylprolyldipeptide ; GVS-111 ; pharmacokinetics ; blood-brain barrier permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Pharmacokinetics of GVS-111, a new acylprolyldipeptide with nootropic properties and its penetration across the blood-brain barrier were studied in rats using HPLC. It was found that the dipeptide is absorbed in the gastrointestinal tract, enters the circulation, and penetrates through the blood-brain barrier in an umodified state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02439270
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  • 107
    Electronic Resource
    Electronic Resource
    The Need for Two-Dimensional Gas Chromatography: Extent of Overlap in One-Dimensional Gas Chromatograms (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 235-244 
    Details
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional GC ; peak overlap ; statistical-overlap theory ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The need for two-dimensional gas chromatography is justified by the extent of peak overlap in one-dimensional gas chromatograms (GCs) of complex mixtures. Such overlap was predicted long ago by statistical-overlap theory (SOT). In this paper, SOT is conceptually reviewed and its predictions are shown to be quantitatively accurate. GCs of complex mixtures of polychlorinated biphenyls, pyridine- and nitrogen-containing polynuclear aromatic hydrocarbons, tetrachlorodibenzo-p-dioxins and dibenzofurans, fatty acid methyl esters, flavors and fragrances, and naphtha were simulated by commercial GC software on DB-1, DB-5, and Stabilwax stationary phases. The numbers of peak maxima in the GCs agreed with predictions of SOT, when the interval of time between successive peaks of pure compounds was described by Poisson statistics. This agreement was realized even though the time intervals actually are deterministic, not statistical. In addition, the numbers of mixture components were predicted with accuracy by regression of peak numbers against SOT. Similar regressions have been reported before, but the theory used here is more sophisticated and its predictions consequently are more accurate. Future directions for finalizing SOT are suggested.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 108
    Electronic Resource
    Electronic Resource
    Enantioselective HRGC Separation of Toxaphene Congeners by Ethylated γ-Cyclodextrins (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 304-308 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselectivity ; gas chromatography ; ethylated γ-cyclodextrin ; toxaphene ; enantiomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The enantioselectivity of three batches of octakis-(2,3,6-tri-O-ethyl)-γ-cyclodextrin (TEG-CD), which differed significantly in their degree of ethylation, is reported for toxaphene congeners. The cyclodextrin composition was determined by high performance liquid chromatography-mass spectrometry. Columns prepared with almost fully ethylated cyclodextrin showed no enantiomer separation. Increasing the average number of free OH groups up to an optimum of 3.8 allowed to resolve the following toxaphene congeners into enantiomers: Parlar no. 11, 12, 15, 21, 25, 32, 38, 42.1, 42.2, 50, 51, 56, 58, 59, 62, 69 as well as B8-1412. More free OH groups did not improve the enantiomer resolution. The structure of the polysiloxane used for dilution of TEG-CD also had an influence on the enantiomer separations achieved. Compared to OV 1701-OH, the use of PS 086 significantly improved the enantiomer resolutions of the separated congeners. However, neither increasing the column length nor the cyclodextrin amount in the stationary phase led to better separation results.
    Additional Material: 2 Ill.
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  • 109
    Electronic Resource
    Electronic Resource
    Reversed-Phase High-Performance Liquid Chromatographic Separation and Determination of 4-Amino-azobenzene-4′,5-disulfonic Acid and Related Products in Industrial Wastewater Effluents (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 329-332 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; industrial wastewater ; process development ; 4-amino-azobenzene-4′,5-disulfonic acid (AABDS) ; 4-amino-azobenzene (AAB) ; 4-amino-azobenzene-4′-sulfonic acid (AABS) ; 4-amino-azobenzene-4′,3,5-trisulfonic acid (AABTS) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A simple and rapid reversed-phase high-performance liquid chromatographic method for the separation and determination of 4-amino-azobenzene-4′,5-disulfonic acid (AABDS) and its process-related impurities was developed. The separation was achieved on a μ-Bondapak C18 column using 0.15 M ammonium sulfate-acetonitrile (55:45) (v/v) as eluent. A UV-visible spectrophotometric detector fixed at 386 nm was used both for detection and quantitation. The method was used not only for quality assurance but also for process development and wastewater management of AABDS.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 110
    Electronic Resource
    Electronic Resource
    Mixed Mode Retention and the Use of Competing Acid for the Ag+-HPLC Analysis of Underivatized Conjugated Linoleic Acids (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 317-323 
    Details
    ISSN: 0935-6304
    Keywords: Conjugated linoleic acids ; underivatized ; Ag+-HPLC ; resolution ; mixed mode retention ; hydrogen bonding ; competing acid ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Fatty acids (FAs) and fatty acid residues are generally methylated and analyzed by GC. The reasons for this are partly historic and partly because of the sensitivity advantage of flame ionization detection over UV absorption by the carboxylic acid functionality in saturated FAs. However, for strongly absorbing unsaturated acids such as the conjugated linoleic acids (CLAs), the sensitivity advantage is greatly reduced. Hence there seems little reason to waste time and introduce errors associated with methylation. Remarkably, this appears not to have been recognized. In this paper we describe our method development for the analysis of underivatized CLAs by silver ion HPLC separation on the ChromSpher Lipids column. Using mobile phases previously optimized for the analysis of the methylated CLAs, retention is excessive and a competing acid is required. Various combinations of small concentrations of acetic acid (3.0-2.5%) with acetonitrile (0.0-0.025%), respectively, yield similar resolution and run times. As well as its role as a competing acid, acetic acid acts as a general strong solvent and thus can be used alone as a modifier (without acetonitrile). However, for slightly shorter run times a mobile phase of 2.5% acetic acid and 0.025% acetonitrile was chosen as the optimum mobile phase for analysis. The separation of the free CLAs is clearly superior to those previously published and obtained in this study for the methylated CLAs. The additional specific strong interactions of the underivatized CLAs seem certain to be due to hydrogen bonding between the CLA carboxylic acid functionality and the large number of residual silanols on the surface of the silica support of the stationary phase.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 111
    Electronic Resource
    Electronic Resource
    Design, Preparation and Application of a New π-Basic Chiral Stationary Phase for the Liquid Chromatographic Separation of Enantiomers (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 333-337 
    Details
    ISSN: 0935-6304
    Keywords: Liquid chromatography ; chiral separation ; chiral stationary phase ; separation of enantiomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new reciprocal π-basic chiral stationary phase (CSP) was designed based on the reciprocity conception of chiral recognition and prepared starting from (S)-leucine. The CSP thus prepared was applied in resolving various π-acidic N-(3,5-dinitrobenzoyl)-α-amino amides and esters and found to be very effective. Especially, N-(3,5-dinitrobenzoyl)-α-amino N,N-dialkyl amides were resolved very well on the new reciprocal CSP. From the chromatographic resolution results and based on the reciprocity conception of chiral recognition with the aid of Corey/Pauling/Koltan (CPK) molecular model studies, a chiral recognition mechanism which utilizes π-π interaction and simultaneously two hydrogen bonding interactions between the CSP and the analyte has been proposed. The CSP prepared in this study was also successful in resolving 3,5-dinitrophenylcarbamate derivatives of 2-hydroxycarboxylic acid esters.
    Additional Material: 4 Ill.
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  • 112
    Electronic Resource
    Electronic Resource
    Potential of Flame Ionization Detection Coupled On-Line with Microcolumn Liquid Chromatography Using Aqueous Eluents and an Eluent-Jet Interface (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 309-316 
    Details
    ISSN: 0935-6304
    Keywords: μLC ; FID ; LC-FID ; carbohydrates ; amino acids ; alcohols ; phosphonic acids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The potential of the on-line coupling of microcolumn liquid chromatography (μLC) using aqueous eluents with a flame ionization detector (FID) was evaluated. An eluent-jet interface was modified to allow the efficient introduction of the eluent into the FID. The potential of the method is demonstrated by the μLC-FID determination of lower alcohols and bis(2-hydroxyethylthio)alkanes on porous and non-porous stationary phases, respectively. Flow injection analysis (FIA)-FID experiments with highly polar, thermolabile, semi-volatile and non-volatile compounds like amino acids, organic acids, alkylphosphonic acids, and carbohydrates showed the developed configuration to be a promising approach for the detection of a wide range of analytes. Compared with a nebulization interface, the eluent-jet interface showed 4-10 times higher peaks for citric acid. Detection limits by FIA for all compounds were in the range of 0.2-5 ng injected. With ribose as test compound, plots of peak height vs. amount injected showed good linearity (r2 〉 0.999) in the range of 75-12,000 μg/mL. The repeatability showed relative standard deviations of less than 5%.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 113
    Electronic Resource
    Electronic Resource
    Separation and Determination of Phenolic Antioxidants by HPLC with Surfactant/n-Propanol Mobile Phases (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 324-328 
    Details
    ISSN: 0935-6304
    Keywords: Antioxidants ; propyl gallate ; octyl gallate ; dodecyl gallate ; butylated hydroxyanisole ; butylated hydroxytoluene ; reverse-phase liquid chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The influence of cationic and anionic surfactants and short-chain alcohols in the mobile phase on the retention of five antioxidants has been studied. The solutes chosen were butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and propyl, octyl, and dodecyl gallates (PG, OG, DG).The surfactants were hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), and n-propanol (PrOH) was the selected alcohol. A simple isocratic reversed-phase method for the antioxidant determination is proposed. Separation of five primary antioxidants takes 18 min with the mobile phase SDS 0.10 M/H3PO4 0.01 M/PrOH 30%. Variation of the percentage of alcohol in the mobile phase permits optimization of the retention times of the antioxidants. Detection limits in the pg range were obtained for the all solutes. The method was used to determine the antioxidants in olive oil at three different levels, giving mean recoveries close to 100% for all the solutes (BHA 102%, PG 99%, OG 99%, DG 99%) except BHT (84%).
    Additional Material: 3 Ill.
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  • 114
    Electronic Resource
    Electronic Resource
    Analysis of Polyunsaturated Fatty Acids Using High Performance Liquid Chromatography - Atmospheric Pressure Chemical Ionization Mass Spectrometry (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 338-342 
    Details
    ISSN: 0935-6304
    Keywords: Polyunsaturated fatty acids (PUFA) ; high performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-MS with APCI) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis of polyunsaturated fatty acids using high performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry is described. The standard fatty acid methyl esters from 16 to 22 carbons were analyzed by LC-MS with APCI. The effect of orifice voltage and total carbon atoms versus number of double bonds in each homologue on the mass spectra is discussed. The correction coefficients for homologues from saturated fatty acids to hexaenoic acid are also mentioned.
    Additional Material: 4 Ill.
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  • 115
    Electronic Resource
    Electronic Resource
    Supercritical Fluid Sample Introduction of Unstable Organometallic Compounds in Supercritical Fluid Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 386-388 
    Details
    ISSN: 0935-6304
    Keywords: On-line SFE-SFC ; organometallics ; purity testing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 116
    Electronic Resource
    Electronic Resource
    Supercritical Fluid Extraction of Euphorbia rigida (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 397-400 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction ; capillary GC ; hydrocarbons ; bio-oil ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 3 Ill.
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  • 117
    Electronic Resource
    Electronic Resource
    Comparison of Three Sorbents for Clean-Up of Mixed Aliphatic Hydrocarbons, PCBs, and PCTs Prior to Simultaneous Determination by GC-ECD/FID (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 401-404 
    Details
    ISSN: 0935-6304
    Keywords: Clean-up ; aliphatic hydrocarbons ; organochlorine compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 118
    Electronic Resource
    Electronic Resource
    Simultaneous Speciation Analysis of Fe(II) and Fe(III) in Mineral Samples by Using Capillary Electrophoresis (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 430-436 
    Details
    ISSN: 0935-6304
    Keywords: Speciation ; digestion ; capillary electrophoresis ; ferrous ; ferric ; mineral analysis ; complexation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Capillary electrophoresis is used as a means of cation separation for cationic speciation analysis. Acceptable separation of ferrous and ferric iron was achieved by using a mixed complexing agent run buffer which gave stable species in solution. These iron species, and total iron, were determined simultaneously in certified reference materials with a single digestion step. A variety of digestion techniques were compared, primarily for their non-oxidative capabilities in order to preserve the oxidation state of iron in the mineral samples. The most favorable recoveries resulted from a continuous flow nitrogen purge technique. Total iron levels obtained from the CE method were compared with those determined by two spectroscopic techniques, with similar results obtained using the different instrumental methods.
    Additional Material: 3 Ill.
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  • 119
    Electronic Resource
    Electronic Resource
    Simultaneous Determination of Organic Acids in Wine Samples by Capillary Electrophoresis and UV Detection: Optimization with Five Different Background Electrolytes (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 647-652 
    Details
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; UV detection ; organic acids ; background electrolyte optimization ; wine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A simple technique is described for the routine capillary electrophoretic determination of organic acids in wine samples. Several aromatic and non-aromatic compounds, including phthalic acid, benzoic acid, sorbic acid, boric acid, and phosphate, were evaluated as background electrolytes in order to obtain the highest resolution and detection sensivity. Factors that affect capillary electrophoretic separation such as the concentration and pH of the background electrolyte (BGE), the concentration of the electroosmotic flow modifier (EOF), and methanol addition to the electrolyte were investigated systematically. Tartaric, malic, succinic, acetic, and lactic acids were determined simultaneously in approximately six minutes using an electrolyte containing 3 mM phosphate and 0.5 mM myristyltrimethylammonium bromide (MTAB) as electroosmotic flow modifier at pH 6.5. This method is quantitative, with recoveries in the 90-102% range and linear up to 50 mg L-1. The precision is better than 1% and the procedure shows the appropriate sensibility, with detection limits between 0.015 and 0.054 mg L-1. The proposed method was successfully employed for the determination of organic acids in wine samples by direct sample injection after appropriate dilution and filtration.
    Additional Material: 5 Ill.
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  • 120
    Electronic Resource
    Electronic Resource
    Regenerable MnO-based Glass Absorber Tube with Press-Fit Connection for Easy Post-Injector Evaluation of Carrier Gases Oxygen Contamination (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 688-692 
    Details
    ISSN: 0935-6304
    Keywords: Solid oxygen scavenger ; carrier gas purity ; manganous oxide ; glass press-fit connections ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 6 Ill.
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  • 121
    Electronic Resource
    Electronic Resource
    Identification and Determination of Active Components in Gentiana rigescens Franch by Micellar Electrokinetic Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 697-698 
    Details
    ISSN: 0935-6304
    Keywords: Gentiana rigescens Franch ; gentiopicroside ; swertiamarin ; MEKC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 2 Ill.
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    Applications of PTV Injectors for Problem Solving in the Petrochemical Industry. Thermal Desorption with GC and GC-MS (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 479-484 
    Details
    ISSN: 0935-6304
    Keywords: Programmable temperature vaporizing injection (PTV) ; thermal desorption ; gas chromatography ; mass spectrometry ; plasticizers ; polyethylene ; food wrapping film ; explosive powders ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Programmable Temperature Vaporizing Injection (PTV) has been used extensively as a means of injecting large volumes of samples to enhance sensitivity. This paper describes the use of PTV injection in the desorption mode for the analysis of a range of solid samples, and four examples of this application are described in detail. Detection by mass spectrometry was used extensively as a means of identification of the components in the various samples which were characterized.
    Additional Material: 12 Ill.
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  • 123
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    Electronic Resource
    Direct High-Performance Liquid Chromatographic Enantioseparation of β-Methyl-Substituted Unusual Amino Acids on a Quinine-Derived Chiral Anion-Exchange Stationary Phase (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 628-636 
    Details
    ISSN: 0935-6304
    Keywords: High-performance liquid chromatography ; β-methyl amino acids ; enantioseparation ; quinine-derived chiral stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quinine-derived chiral anion-exchange stationary phase was used for the direct high-performance liquid chromatographic separation of the enantiomers of the N-protected unusual β-substituted α-amino acids, β-methylphenylalanine, β-methyltyrosine, β-methyltryptophan, and β-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid. The readily prepared 2,4-dinitrophenyl and tert-butyloxycarbonyl derivatives were well separated, and in most cases the separation of all four stereoisomers of these β-methyl-α-amino acids could be obtained in one chromatographic run. The elution sequences of the enantiomers of the different derivatives were determined and revealed a dependence on the type of the N-protecting group. In this context, the effects of different protecting groups (acetyl, tert-butyloxycarbonyl, benzoyl, 3,5-dinitrobenzoyl, benzyloxycarbonyl, 3,5-dinitrobenzyloxycarbonyl, 2,4-dinitrophenyl, and 9-fluorenylmethoxycarbonyl) on the chromatographic behavior were investigated.
    Additional Material: 6 Ill.
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  • 124
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    Electronic Resource
    Optimization and Validation of a Fast Liquid Gradient for Determination of Prominent Flavan-3-ols and Flavonols in Fresh Vegetables (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 637-643 
    Details
    ISSN: 0935-6304
    Keywords: HPLC ; fast separation ; flavan-3-ol ; flavonols ; vegetables ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A fast high-performance liquid chromatography method was used for analysis of prominent flavan-3-ols and flavonols in vegetables. Gradient elution with phosphoric acid-acetonitrile mixtures and phosphoric acid-methanol mixtures allowed fast and complete separation of the studied phenolic compounds within analysis times less than 10 min. The development of two elution gradients using methanol and acetonitrile as modifiers proved to be an excellent approach for the verification of the real polyphenolic composition in vegetables samples because the two optimized methods allowed the separation of the same number of compounds in the same elution order. Diode-array detection was employed for the provisional identification of phenolic compounds that were not available as standards. We preferred methanol as a modifier because it was less toxic and cheaper than acetonitrile. Detection limits ranged between 0.12 and 0.59 μg mL-1. High recoveries of phenolics from fresh vegetables were measured in all studied cases, independent of the phenolic structure, matrix, and vegetable in question. High levels of procyanidins between 150 and 450 mg kg-1 were found in all studied vegetables. Quantification of quercetin and kaempferol glycosides was only possible in marrow and onion, respectively.
    Additional Material: 3 Ill.
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  • 125
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    Electronic Resource
    Characterization of Inulins by Capillary Electrophoresis with Laser Induced Fluorescence Detection (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 656-658 
    Details
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis (CE) ; laser induced fluorescence detection (LIFD) ; fluorescein isothiocyanate (FITC) ; inulin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 3 Ill.
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  • 126
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    Linear and Quadratic Relationships between Retention and Organic Modifier Content in Eluent in Reversed Phase High-Performance Liquid Chromatography: A Systematic Comparative Statistical Study (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 667-676 
    Details
    ISSN: 0935-6304
    Keywords: Reversed-phase high performance liquid chromatography (RP-HPLC) ; relationships between retention and eluent composition ; linear and quadratic models ; statistical comparison of ; evaluation of HPLC columns ; stationary phases ; lipophilicity/hydrophobicity ; log kw ; log P ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Statistical evaluation of linear and quadratic models of chromatographic retention was performed. The relationships describing retention were derived for a set of 23 carefully selected test analytes chromatographed on 18 HPLC columns using methanol-water or acetonitrile-water solutions as mobile phase. It was ascertained whether the square term in the quadratic model improves the description of chromatographic retention in a statistically significant manner. It was also checked whether the retention data extrapolated to a hypothetical neat water eluent (log kw) obtained with the two models and the two organic modifiers are equivalent or should be considered different. The research proved that both models yield similar results and the extrapolated log kw values do not differ statistically significantly in the case of methanol-containing mobile phases. In the case of acetonitrile-water systems the log kw values obtained with linear and quadratic models are normally statistically different. Correlation analysis for log kw vs. log P parameters was performed for data determined on six columns. The best correlations were achieved employing log kw data derived with the linear model for methanol/water systems.
    Additional Material: 3 Ill.
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  • 127
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    Determination of Molecular Weight Distribution of Lignin Derivatives by Aqueous Phase High Performance Size Exclusion Chromatography (HPSEC) (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 693-696 
    Details
    ISSN: 0935-6304
    Keywords: High performance size exclusion chromatography ; molecular weight ; lignin derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 4 Ill.
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  • 128
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    Electronic Resource
    Identification and Quantification of Thiaarenes in the Flue Gas of Lignite-Fired Domestic Heating (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 457-473 
    Details
    ISSN: 0935-6304
    Keywords: Domestic lignite heating emissions ; isokinetic sampling ; polyaromatic sulfur heterocycles (PASH) ; thiaarenes ; atomic emission detection (AED) ; pulsed flame photometric detection (PFPD) ; high resolution mass spectrometry (HRMS) ; retention indices ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Lignite briquettes with different sulfur contents were burned in a common type of domestic heating system. The levels of polycyclic aromatic sulfur heterocycles (PASH, thiaarenes) and their alkylated and phenylated derivatives in the flue gas were determined. The analytical method described comprises isokinetic sampling, GC/full scan-MS for screening analysis, HPLC/wavelength programmable fluorescence detection (selected PAHs used as internal standards for GC), GC/atomic emission detection or GC/pulsed flame photometric detection (sulfur-selective detection of thiaarenes), GC/high resolution MS (verification and quantification of thiaarenes), and the determination of the gas chromatographic retention indices. In total 57 thiaarene species (individual compounds if possible and groups of isomeric compounds such as alkylated/phenylated species) were identified, their retention indices determined, and quantified as flue gas emission concentrations. Not only thiophene-related thiaarenes but also species with two sulfur atoms in the molecule (e. g. thienothiophene derivatives) were found. The thiaarene emission pattern is discussed, as is the correlation between the thiaarene emissions and the sulfur content of the different briquette types burned.
    Additional Material: 11 Ill.
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  • 129
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    Electronic Resource
    Advances in Flavor Research (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 489-496 
    Details
    ISSN: 0935-6304
    Keywords: Flavor ; odorant ; headspace ; GC ; interaction ; electronic nose ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In order to understand the flavor of foods a multitude of scientific investigations have been carried out and a number of analytical tools for flavor research developed in the last few decades. Initially, scientific investigations focused mainly on the identification of all compounds that could contribute to the flavor. Olfactory GC techniques permitted the division of identified volatiles into odor-active and non-odor-active. Many techniques were developed to enhance the quality and the information content of the flavor results. Since the early 1990s, analytical investigations have dealt with interactions between food matrices and flavor compounds and the human influence on the retardation of odorants. New analytical methods concentrate on the headspace of the sample by using static or dynamic headspace analysis, or deal with measurements of volatile release in the mouth by a novel nose sampler and oral vapor GC. These useful tools clarify the effects of breathing, chewing, and saliva flow on flavor release. Though the human nose performs well at low concentrations of odorants, it is a medium-term aim to replace the use of the human nose by analytical techniques. Future investigations will probably deal with the interactions of odorants and the human receptors and it is mainly these receptors that will play a key role in aroma research. By analysis of the effects of odorants on the receptors the mechanisms of odor perception will be elucidated. This will enable the development of supporting analytical tools like electronic noses that really do function as noses, or “neural networks”.
    Additional Material: 9 Ill.
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  • 130
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    Determination of Scoparone in Citrus Roots by Micellar Electrokinetic Capillary Chromatography (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 519-521 
    Details
    ISSN: 0935-6304
    Keywords: Scoparone ; phytoalexin ; citrus ; MEKC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new MEKC method has been developed to determine the amount of the phytoalexin, scoparone, in Citrus roots. The separation and analysis was achieved with a running buffer of 100 mM SDS, 25 mM phosphate and 12% (v/v) methanol pH 6.2. Separation was performed at 12 kV with 25°C and UV detection at 200 nm. A near complete recovery of scoparone was obtained with the extraction procedure. The MEKC method was compared with a fluorescence TLC method. The detection limit for scoparone with the MEKC method (2 μg/mL) was better than the TLC method (10 μg/mL).
    Additional Material: 2 Ill.
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  • 131
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    Electronic Resource
    Enhancing the Limit of Detection for Comprehensive Two-Dimensional Gas Chromatography (GC×GC) using Bilinear Chemometric Analysis (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 215-224 
    Details
    ISSN: 0935-6304
    Keywords: Bilinear signal enhancement ; two-dimensional comprehensive gas chromatography ; chemometrics ; GC ; GRAM ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The chemometric method referred to as the generalized rank annihilation method (GRAM) is used to improve the precision, accuracy, and resolution of comprehensive two-dimensional gas chromatography (GC×GC) data. Because GC×GC signals follow a bilinear structure, GC×GC signals can be readily extracted from noise by chemometric techniques such as GRAM. This resulting improvement in signal-to-noise ratio (S/N) and detectability is referred to as bilinear signal enhancement. Here, GRAM uses bilinear signal enhancement on both resolved and unresolved GC×GC peaks that initially have a low S/N in the original GC×GC data. In this work, the chemometric method of GRAM is compared to two traditional peak integration methods for quantifying GC×GC analyte signals. One integration method uses a threshold to determine the signal of a peak of interest. With this integration method only those data points above the limit of detection and within a selected area are integrated to produce the total analyte signal for calibration and quantification. The other integration method evaluated did not employ a threshold, and simply summed all the data points in a selected region to obtain a total analyte signal. Substantial improvements in quantification precision, accuracy, and limit of detection are obtained by using GRAM, as compared to when either peak integration method is applied. In addition, the GRAM results are found to be more accurate than results obtained by peak integration, because GRAM more effectively corrects for the slight baseline offset remaining after the background subtraction of data. In the case of a 2.7-ppm propylbenzene synthetic sample the quantification result with GRAM is 2.6 times more precise and 4.2 times more accurate than the integration method without a threshold, and 18 times more accurate than the integration method with a threshold. The limit of detection for propylbenzene was 0.6 ppm (parts per million by mass) using GRAM, without implementing any sample preconcentration prior to injection. GRAM is also demonstrated as a means to resolve overlapped signals, while enhancing the S/N. Four alkyl benzene signals of low S/N which were not resolved by GC×GC are mathematically resolved and quantified.
    Additional Material: 5 Ill.
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  • 132
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    Electronic Resource
    Design and Implementation of Comprehensive Gas Chromatography with Cryogenic Modulation (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 245-252 
    Details
    ISSN: 0935-6304
    Keywords: LMCS ; cryogenic modulation ; comprehensive gas chromatography ; GC×GC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comprehensive gas chromatography is the realization of true continuous multidimensional (dual column) gas chromatography. The key requirement in the comprehensive GC experiment is that the second dimension analysis is completed in a rapid time-frame compared to the elution of components in the first dimension, and that the two coupled dimensions represent ‘orthogonal’ analyses towards the analytes to be separated. The former normally necessitates pulsing of contiguous segments of each chromatographic band from the first to the second dimensions. The two dimensions should be in fluid communication. The comprehensive GC×GC experiment passes all the column flow from the first column to the second column, leading to no sample loss, but this also requires a suitable method for time- or zone-compression of the band to be pulsed to the second column. The final pulse should be narrow, and should be delivered to the second column quickly. A simple procedure can achieve this using the cryogenic modulator that has been recently described by this group. The system uses a cryogenic trap which can be moved away from the cooled zone of the column faster than 10 ms. A fast-acting pneumatic ram achieves this performance. The cooled column heats up to the prevailing oven temperature within 10-15 ms. Molecules as volatile as C5 alkanes or small aromatics will be fully retained by the trap within the period of modulation used for GC×GC. The technique is simple to implement and requires no special column connections. Using a gas chromatograph which allows control of external events and can acquire from a detector at 50 Hz or faster, and a timing controller for modulation, the comprehensive result can easily and effectively be achieved.
    Additional Material: 7 Ill.
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  • 133
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    Relationships between Retention Factors and Analyte Hydrophobicity on Cyanopropyl and n-Octadecyl Bonded Silicas, Cross-Linked Polymers and Porous Graphitic Carbon Stationary Phases. Consequences for the Trace Analysis of Highly Polar Organic Compounds (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 437-444 
    Details
    ISSN: 0935-6304
    Keywords: Retention factors ; styrene divinylbenzene polymer ; porous graphitic carbon ; solid-phase extraction ; water analysis ; polar organic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---LC retention data have been measured using various stationary phases with an emphasis on highly polar to moderately polar neutral organic compounds having octanol-water partition coefficients (Kow) in log units between 0 and 3. The relationships between the retention factor measured in water and the octanol-water partition coefficient are linear but with different slopes for octadecyl (C18) silicas, and two polystyrene divinylbenzene (PS-DVB) phases with low and high surface areas. These relationships confirm that highly cross-linked polymers can provide more than 1000-times higher retention values than C18 silicas for moderately polar analytes but close values for highly polar ones. They also explain why C18 silicas and polymers are equivalent for the separation of very polar analytes. In contrast, due to a different retention mechanism, no relation exists between the retention shown by porous graphitic carbons (PGC) and analyte hydrophobicity, but highly polar analytes are in general much more strongly retained than by any other sorbent. The potential of PGC for both the extraction and the separation of analytes is shown. Due to the difference in separation mechanism, PGC is the analytical phase that should be used for confirmation of the identity of analytes instead of a cyanopropylsilica column as recommended in some environmental procedures. Applications are presented for the trace-determination of triazines and polar degradation products in ground and surface water with detection limits below the 0.1 μg/L level.
    Additional Material: 5 Ill.
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  • 134
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    Studies on the Use of Commercial Capillary Gas Chromatographic Columns as Diffusion Denuders (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 449-454 
    Details
    ISSN: 0935-6304
    Keywords: Denuders ; isolation and enrichment ; analysis ; volatile organic compounds ; partition coefficients Kfs ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The possibility of using a piece of gas chromatographic capillary column as a tubular denuder for isolation and enrichment of organic pollutants present in air was studied. The partition coefficients (Kfs) of typical organic pollutants (benzene, chlorobenzene, toluene) between the gaseous phase and the denuder sorption layer were determined and effects of analyte concentration in the gaseous phase and gas flow rate on partitioning were studied. The partition coefficients were found to be constant in the studied range of concentration and gaseous mixture flow rate. A piece of a capillary column coated with polydimethylosiloxane can be used as a tubular denuder.
    Additional Material: 2 Ill.
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  • 135
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    Headspace Sorptive Extraction (HSSE) in the Headspace Analysis of Aromatic and Medicinal Plants (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 539-546 
    Details
    ISSN: 0935-6304
    Keywords: Headspace sampling ; Headspace Sorptive Extraction (HSSE) ; SPME ; aromatic plants ; medicinal plants ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new sampling technique, Headspace Sorptive Extraction (HSSE), is here applied for the first time to the headspace sampling of medicinal and aromatic plants. The analyte partition coefficient between HSSE-PDMS stir bar and sample headspace (K1), the concentration factor (CF), the reproducibility, and the minimum recoverable amount were determined by analyzing standard solution of high volatility C5-C7 compounds with different polarities and structures (cyclohexane, propyl acetate, hexanal, 1-hexen-3-ol, isoamyl acetate, and 2-heptanol). Four aromatic and medicinal plants, viz. rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), thyme (Thymus vulgaris L.), and valerian (Valeriana officinalis L.) were analyzed by HSSE-GC with PDMS stir bars, and their concentration capacity was compared with those of S-HS and HS-SPME with different fibers. HSSE showed very high concentration capability with both standard and real sample components.
    Additional Material: 3 Ill.
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  • 136
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    Considerations on Static and Dynamic Sorptive and Adsorptive Sampling to Monitor Volatiles Emitted by Living Plants (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 547-553 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; static and dynamic headspace sampling ; sorptive and adsorptive extraction ; plant volatiles ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Static and dynamic headspace sampling have been applied for the enrichment of volatiles emitted by living plants. For solid phase microextraction (SPME) the sorptive fibers polydimethylsiloxane (PDMS) and polyacrylate (PA) have been compared and, in accordance with the like-like principle, polar compounds exhibit more affinity for the PA fiber while apolar solutes favor the PDMS fiber. For dynamic sampling, tubes packed with PDMS particles show greater inertness than Tenax; some Tenax decomposition products, e.g. benzaldehyde and acetophenone, interfere with the analyses. With PDMS particles operated in the breakthrough mode, the obtained profiles are similar to those obtained by SPME on the PA fiber. Recoveries relative to a packed PDMS bed are 85% for Tenax, 2.4% for SPME-PDMS, and 6.2% for SPME-PA.
    Additional Material: 5 Ill.
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    Influence of renal failure, rheumatoid arthritis and old age on the pharmacokinetics of diflunisal (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 165-174 
    Details
    ISSN: 1432-1041
    Keywords: diflunisal ; pharmacokinetics ; healthy volunteers ; kidney failure ; rheumatoid arthritis ; aged subjects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The single-dose plasma kinetics of diflunisal was studied in healthy young and old subjects, in patients with rheumatoid arthritis, and in patients with renal failure. The plasma and urine kinetics of the glucuronidated metabolites of diflunisal were studied in the healthy elderly subjects and in the patients with renal failure. In addition, the multiple-dose plasma kinetics of diflunisal was assessed in healthy volunteers and in patients with rheumatoid arthritis. After a single dose of diflunisal the terminal plasma half-life, mean residence time and apparent volume of distribution were higher in elderly subjects than in young adults. No difference was observed in any pharmacokinetic parameter between age-matched healthy subjects and patients with rheumatoid arthritis. The elimination half-life of unchanged diflunisal was correlated with the creatinine clearance (r=+0.89) and its apparent total body clearance exhibited linear dependence on creatinine clearance (r=+0.78). In patients with renal failure, the terminal plasma half-life and mean residence time of diflunisal were prolonged. The renal and apparent total body clearances were lower, the mean apparent volume of distribution was higher and the mean area under the concentration-time curve extrapolated to infinity (AUC) was greater in the renal failure patients than in controls. The plasma concentration of the glucuronidated metabolites rapidly rose to levels above those of unchanged drug in renal patients, whereas they were lower than those of unchanged diflunisal in controls. The AUC (0–96 h) of diflunisal glucuronides in the patients was four-times that in controls, and the terminal elimination half-life of the glucuronides was prolonged in them. The renal excretion and clearance of diflunisal glucuronides were reduced when renal function was impaired. After multiple dosing, the pre-dose steady-state plasma-concentration increased with decreasing creatinine clearance (r=-0.79). When the plasma concentration exceeded 200 µmol·1−1, the elimination half-life was doubled, due to partial saturation of diflunisal conjugation. This finding suggests that lower doses could be used in long-term treatment. Thus, old age and arthritic disease appear to have little influence on the kinetics of diflunisal in the absence of renal functional impairment. Ordinary doses can be given for short term treatment of elderly patients with or without RA. In patients with renal failure, however, reduced doses of diflunisal are recommended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609190
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    Pharmacokinetics of ipratropium bromide after single dose inhalation and oral and intravenous administration (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 189-194 
    Details
    ISSN: 1432-1041
    Keywords: ipratropium bromide ; radioceptor assay ; pharmacokinetics ; inhalation ; systemic administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Single doses of ipratropium bromide were administered intravenously, orally and by slow inhalation to ten healthy male volunteers. The plasma level after oral administration followed a low but broad plateau persisting for several hours. After i.v. administration the kinetic parameters were: Vc=25.9 l, Vα=13.1 l, Vβ=338 l, $$t_{{1 \mathord{\left/ {\vphantom {1 {2_\alpha }}} \right. \kern-\nulldelimiterspace} {2_\alpha }}} = 3.85\min $$ , $$t_{{1 \mathord{\left/ {\vphantom {1 {2_\beta }}} \right. \kern-\nulldelimiterspace} {2_\beta }}} = 98.4\min $$ , AUC=15.0 h · ng/ml, kel=11.8 l/h and total clearance is 2325 ml/min. The bioavailability was 3.3% (range 0.9–6.1%) on comparing the plasma AUCs following i.v. and 20 mg oral administration. The cumulative renal excretion (0–24 h) after i.v. administration was compared with that after oral administration and inhalation. Following oral administration, the apparent systemic availability was around 2%, and after inhalation it was 6.9%. In comparison with oral placebo administration, only after i.v. administration was there a significant change in heart rate (from 63.7 to 90.2 beats/min). The systolic blood pressure rose from 115.1 to 119.6 mm Hg and the diastolic blood pressure from 68.3 to 78.3 mm Hg.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609193
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  • 139
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    A pharmacokinetic study of the active metabolite of nabumetone in young healthy subjects and older arthritis patients (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 299-305 
    Details
    ISSN: 1432-1041
    Keywords: nabumetone ; rheumatoid arthritis ; pharmacokinetics ; old patients ; NSAID
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have performed a detailed pharmacokinetic study of the plasma concentrations of the major active metabolite of nabumetone, 6-methoxy-2-naphthylacetic acid (6 MNA), attained after a single dose and during chronic administration comparing the results of a group of young healthy volunteers with those of a group of elderly arthritic patients. The latter had higher peak plasma concentrations of 6MNA and slower rates of elimination but there is no tendency for the drug to accumulate unpredictably in the old. Disease activity also influences plasma concentration, those with more active disease, and lower serum albumin concentrations had lower AUC values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558163
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  • 140
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    Paracetamol disposition and metabolite kinetics in patients with chronic renal failure (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 291-297 
    Details
    ISSN: 1432-1041
    Keywords: paracetamol ; renal failure ; drug disposition ; polar metabolites ; cumulation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition of paracetamol following an oral dose of 1.0 g was compared in 10 healthy volunteers, 7 patients with moderate chronic renal failure and 6 patients with end stage renal failure on maintenance haemodialysis. Paracetamol absorption was normal in the patients with renal failure. The mean plasma half-life of paracetamol from 2 to 8 h was similar in the 3 groups (2.1 to 2.3 h) but from 8 to 24 h it disappeared much more slowly in the renal failure patients (half-life 11.7 compared with 4.9 h in the healthy volunteers). Plasma concentrations of paracetamol glucuronide and sulphate conjugates were greatly increased in the patients with moderate renal failure and the mean plasma half-lives were 30.5 and 21.8 h respectively compared with about 3 h in the healthy volunteers. Plasma concentrations of these metabolites were even higher in the dialysis patients and there was no significant fall over 24 h. The cysteine and mercapturic acid conjugates of paracetamol could only be measured in plasma in the patients with renal failure and concentrations were very low. The fractional urinary recovery of paracetamol and its glucuronide, sulphate, cysteine and mercapturic acid conjugates was similar in healthy volunteers and patients with moderate renal failure. The mean renal clearances of paracetamol and its glucuronide and sulphate conjugates in the healthy volunteers and patients with moderate renal failure were 15.7, 137 and 172, and 5.9, 14.5 and 14.8 ml/min respectively. In the latter patients the mean renal clearances of the cysteine and mercapturic acid conjugates were much greater at 35.4 and 80.2 ml/min. In the patients with moderate renal failure the AUC's of the glucuronide and sulphate conjugates were related to the plasma creatinine and there were significant negative correlations with the renal clearances of these metabolites and total urinary recovery. Marked cumulation of the polar glucuronide and sulphate conjugates of paracetamol would seem inevitable in patients with renal failure and the parent drug is apparently regenerated to a limited extent from retained metabolites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558162
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  • 141
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    Electronic Resource
    Influence of nifedipine therapy on indocyanine green and oral propranolol pharmacokinetics (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 257-260 
    Details
    ISSN: 1432-1041
    Keywords: nifedipine ; propranolol ; indocyanine green ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nine healthy adults were administered indocyanine green (ICG) 0.5 mg·kg−1 IV alone and after the administration of the following oral drugs: nifedipine 10 mg, propranolol 80 mg, propranolol 80 mg and nifedipine 10 mg, and propranolol 80 mg after nifedipine 10 mg every 8 h for 5 days. Heart rate and mean arterial blood pressure (MAP) were also determined. Nifedipine increased ICG clearance by 14% and decreased t1/2 by 26%. Propranolol decreased ICG clearance by 21% and increased t1/2 42%. Nifedipine and propranolol given together increased ICG clearance 63% and decreased t1/2 by 19%. All changes were statistically significant. Propranolol given after multiple doses of nifedipine did not change ICG kinetic parameters. Propranolol Cmax, tmax, oral clearance, and t1/2 did not change after nifedipine therapy. However, partial propranolol AUC values between 0–0.33, 0–0.5, 0–1.0 and 0–1.5 h were significantly larger after single and multiple doses of nifedipine indicating higher propranolol concentrations during the absorption phase. Heart rate and MAP did not change after nifedipine treatment. Similar declines in heart rate and MAP occurred after propranolol alone and propranolol after single and multiple doses of nifedipine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679780
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  • 142
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of ramipril in hypertensive patients with renal insufficiency (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 249-256 
    Details
    ISSN: 1432-1041
    Keywords: ramipril ; renal insufficiency ; hypertension ; pharmacokinetics ; ramiprilat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In an open trial, the pharmacokinetics of ramipril and its active metabolite ramiprilat were studied in 25 hypertensive patients with various degrees of renal insufficiency given 5 mg ramipril p.o. for 14 days. Ramipril was rapidly absorbed and reached a peak concentration after 1–2 h. Cmax was greater in patients with severe renal insufficiency, which might indicate a reduced renal elimination rate, although, the rapid decline of the concentration-time curve for ramipril was almost independent of renal function. The mean initial apparent half-lives on Days 1 and 12, respectively, were 2.8 and 3.4 h (Group I: creatinine clearance 5–15 ml/min), 1.8 and 2.3 h (Group II: creatinine clearance 15–40 ml/min), and 1.9 and 1.9 h (Group III: creatinine clearance 40–80 ml/min). No accumulation was observed after multiple dosing. In contrast, the kinetics of its active acid metabolite ramiprilat was significantly influenced by renal function. The mean times to the peak plasma concentration were 5.7 h in Group I, 4.4 h in Group II and 3.8 h in Group III. The initial decline in plasma ramiprilat was dependent upon renal function; the mean initial apparent half-lives (Days 1 and 12, respectively) were 16.0 and 14.8 h (Group I), 10.1 and 9.5 h (Group II) and 10.6 and 8.0 h (Group III). Mean trough concentrations and absolute accumulation also increased with worsening renal function, and the renal clearance of ramiprilat was significantly correlated with the creatinine clearance. The subsequent long terminal phase at low plasma ramiprilat concentrations represented slow dissociation of the ACE-inhibitor complex. The study indicates that in patients with severe renal insufficiency (creatinine clearance below 30 ml/min) smaller doses of ramipril are required than in patients with normal or borderline renal function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679779
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  • 143
    Electronic Resource
    Electronic Resource
    Effect of ketoconazole and terbinafine on the pharmacokinetics of caffeine in healthy volunteers (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 279-283 
    Details
    ISSN: 1432-1041
    Keywords: ketoconazole ; terbinafine ; microsomal metabolism ; caffeine ; male volunteers ; pharmacokinetics ; drug interaction ; cytochrome P-450
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of single oral doses of ketoconazole 400 mg and terbinafine 500 mg on the hepatic microsomal system have been investigated in 8 healthy male volunteers. Microsomal activity caffeine was assessed by following the metabolism of 3 mg/kg bodyweight i.v. administered 1 h after the drug. The inhibitory effect of terbinafine was more pronounced than that of ketoconazole: clearance was decreased from 1.34 ml·kg−1·min−1 in controls to 1.06 and 1.21 ml·kg−1·min−1, respectively, and the corresponding half-life was increased from 5.8 h in controls to 7.6 and 6.7 h, respectively. The apparent volume of distribution remained unchanged. The serum levels of the antimycotics were within the therapeutic range in each subject. Although all three substances are metabolised by microsomes, the kinetic parameters (Cmax, half-life, elimination constant) of the antimycotics were poorly if at all correlated with the elimination of caffeine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679784
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  • 144
    Electronic Resource
    Electronic Resource
    Lack of effect of repirinast on the pharmacokinetics of theophylline in asthmatic patients (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 301-303 
    Details
    ISSN: 1432-1041
    Keywords: repirinast ; theophylline ; asthma ; drug interaction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A possible pharmacokinetic interaction between theophylline and repirinast has been investigated in asthmatic patients. The kinetics of theophylline was studied in seven adult in-patients given theophylline 400–800 mg b.d. alone and after three weeks of co-administration of repirinast. There was no effect on the kinetics of the combined treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679789
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  • 145
    Electronic Resource
    Electronic Resource
    Haemodialysis of pyrazinamide in uraemic patients (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 309-311 
    Details
    ISSN: 1432-1041
    Keywords: pyrazinamide ; haemodialysis ; pharmacokinetics ; uraemic patients ; drug metabolites ; anti-tuberculous chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of PZA during haemodialysis were determined in 6 patients with chronic renal impairment after a single oral dose of 25.7 (1.9) mg·kg−1. The dialysis clearance of PZA and of its metabolites were: pyrazinamide 132 ml·min−1; pyrazinoic acid 121 ml·min−1; 5-hydroxy-pyrazinamide 107 ml·min−1; 5-hydroxy-pyrazinoic acid 118 ml·min−1. The average amount extracted during a dialysis session of 4.1 h was 926 mg after an oral dose of 1700 mg. The high dialysability shows that PZA can property be administered at the end of each dialysis session in the usual dose of 25 to 30 mg·kg−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679791
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  • 146
    Electronic Resource
    Electronic Resource
    The effect of ageing on the pharmacokinetics of dihydrocodeine (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 375-379 
    Details
    ISSN: 1432-1041
    Keywords: dihydrocodeine ; pharmacokinetics ; young/elderly patients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Although poor renal function reduces clearance of dihydrocodeine in man, and renal impairment occurs with ageing, no significant differences occurred in the handling of single doses of dihydrocodeine between elderly patients and young, normal subjects. After multiple dosing, the maximum concentration was significantly different between the groups, being higher in the elderly. The increase in the area under the curve in the elderly was 25% greater than in the young on chronic therapy. This difference was not statistically significant, but was likely to be of clinical significance. The elderly patients' mean creatinine clearance (61.8 ml per min) was significantly lower than that in the young (137 ml per min), and there was a significant correlation between the half-life at single dosing and the blood urea concentration. Variability in all measurements was marked in both groups, and hence no clear guidelines can be given on therapeutic dosing. The small initial dose with alterations thereafter depending on clinical effect is the best advice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558503
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  • 147
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    Electronic Resource
    Simultaneous study of the pharmacokinetics of intravenous and oral nicardipine using a stable isotope (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 381-385 
    Details
    ISSN: 1432-1041
    Keywords: nicardipine ; first pass effect ; pharmacokinetics ; stable isotope assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The systemic elimination of nicardipine has been studied by an initial oral administration of nicardipine followed 1.25 h later by intravenous injection of the deuterium-labelled molecule (D3 nicardipine). To check that intravenous kinetics was not modified by the oral administration, an i.v. injection of unlabelled nicardipine (D0 nicardipine) was also given. The study was carried out in six healthy male volunteers, aged between 24 and 27 years, according to a Latin square cross-over design. Similar values were found for each kinetic parameter after i.v. administration regardless of whether it was administered alone by that route or with an oral dose. The plasma level-time curves of nicardipine were described by a three open compartment model. The total plasma clearance was about 800 ml/min, the volume of distribution was of the order of 1 l/kg and the half-life of β-elimination ranged from 4 to 5 h. The elimination rate constant β was independent of the route of administration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558504
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  • 148
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    Electronic Resource
    Effect of food on the absorption and pharmacokinetics of prednisolone from enteric-coated tablets (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 423-426 
    Details
    ISSN: 1432-1041
    Keywords: prednisolone ; food intake ; enteric-coated tablets ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Prednisolone absorption and bioavailability of 10 mg enteric-coated (EC) and plain (uncoated) tablets were investigated after fasting and heavy meals (EC only) consumed to satiety in normal healthy volunteers. The same volunteers had also received 16 mg of prednisolone intravenously. In fasted subjects, the absolute bioavailability fraction, as normalised for intravenous doses, of prednisolone from plain tablets was 1.055 and from EC tablets was 0.996. The peak concentrations after plain and EC tablets were 309 and 249 ng/ml attained at 0.98 and 5.14 h, respectively. The means plasma elimination half-lives following the plain, EC tablets and intravenous administration in fasting conditions were 3.73, 3.89 and 3.78 h, respectively. Food interfered with both the absorption and the pharmacokinetics of prednisolone after EC tablets resulting in variability in its plasma levels. In some cases absorption of prednisolone was delayed for 12 h and remained at a measurable level for 24 h. In other cases, a normal absorption pattern was observed. This inter- and intrasubject variability of the effect of food appears to be related to its quantity, constituents and also the subjects physiological characteristics. It is concluded that enteric-coated prednisolone tablets should be administered at least 2 h between meals. However, for more predictable corticosteroid absorption (perhaps thus avoiding the therapeutic failure), plain prednisolone tablets are preferable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558515
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  • 149
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    Electronic Resource
    Comparison of trimethadione and antipyrine as indicators of oxidative drug metabolizing capacity in man (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 629-632 
    Details
    ISSN: 1432-1041
    Keywords: trimethadione ; antipyrine ; metabolite formation ; drug interaction ; cytochrome P-450 ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Ten healthy male volunteers were given trimethadione (TMO) 4 mg/kg and antipyrine (AP) 500 mg alone or concomitantly to determine whether the metabolism of the drugs was mediated by the same or closely related forms of cytochrome P-450. Whether administered alone or together the clearance (CL) and half-life (t1/2) of TMO and AP were the same, and there was a good correlation between the CL and t1/2 of TMO and AP (aloner=0.755 and 0.623, respectively; coadministeredr=0.771 and 0.503, respectively). Excretion of AP and its main metabolite and the clearance for production of AP metabolites after AP was administered alone were not significantly different when TMO and AP were taken together. When the two drugs were administered alone or coadministered, the correlation between the CL of TMO and the excretion of 3-hydroxymethyl-3-norantipyrine (NORA) was close (aloner=0.734, coadministeredr=0.749). The correlation between the CL of TMO and CLm of NORA when TMO and AP were given alone or concomitantly was 0.762 and 0.772, respectively. The findings suggest that TMO metabolism and the formation of NORA in healthy subjects are mediated by a closely related form(s) of the cytochrome P-450 system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637749
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  • 150
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    Electronic Resource
    Pharmacokinetics and tolerance of a new penem antibiotic, FCE 22101, in healthy volunteers after a single intravenous dose (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 633-635 
    Details
    ISSN: 1432-1041
    Keywords: FCE 22101 ; penem antibiotic ; pharmacokinetics ; single dose ; healthy volunteers ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The clinical tolerance and pharmacokinetics of FCE 22101 (sodium (5R, 6S)-6-[(1R)-hydroxyethyl]-2-carbamoyloxymethyl-2-penem-3-carboxylate), a new penem antibiotic, have been studied after giving a single i.v. dose of 4 mg·kg−1 to ten healthy male volunteers. The pharmacokinetics was estimated according to a two-compartment open model. The peak plasma concentration (Cmax) was 15.5 (1.08) µg·ml−1, mean (SEM). FCE 22101 was rapidly cleared from the systemic circulation [ $$t_{1/2\lambda _z } $$ =44.2 (4.2) min; CL=7.21 (0.47) ml·kg−1·min−1]. The mean apparent volume of distribution at steady-state was 246 (16.9) ml·kg−1. The mean residence time relative to the 10 min infusion was 39.4 (1.5)min. Urinary recovery of FCE 22101 showed wide inter-subject variation, ranging from 10.2 to 53.6% of the dose. No subject complained of adverse effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637750
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  • 151
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    Electronic Resource
    Comparative pharmacokinetics of zidovudine (AZT) and its metabolite (G.AZT) in healthy subjects and HIV seropositive patients (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 639-640 
    Details
    ISSN: 1432-1041
    Keywords: zidovudine ; azidothymidine ; pharmacokinetics ; metabolism ; HIV seropositivity ; healthy subjects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637752
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  • 152
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    Electronic Resource
    Almitrine bismesylate disposition in the human digestive tract (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 487-491 
    Details
    ISSN: 1432-1041
    Keywords: almitrine ; drug absorption ; liver metabolism ; pharmacokinetics ; biliary excretion ; metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of almitrine from the upper gastrointestinal tract has been evaluated in 6 healthy volunteers by an intubation technique. Almitrine bismesylate dissolved in malic acid was introduced into the stomach after homogenization with a meal containing the marker14C-polyethylene glycol (PEG) 4000. Unlabeled PEG 4000 was infused into the second part of duodenum throughout the experiment. Samples of the luminal content were collected every 15 min for four hours from the stomach and at the ligament of Treitz. Blood was also collected. Almitrine was neither absorbed from nor metabolized in the stomach. About 37% of the quantity of drug emptied from the stomach was absorbed from the duodenum. Almitrine was detected in plasma 50 min after ingestion of the meal and its plasma concentration-time profile reflected the cumulative gastric emptying rate. The metabolite tetrahydroxy almitrine was found in intestinal samples as soon as unchanged drug was detected in plasma. The intraluminal rate of formation of the metabolite increased with time. The results suggest hepatic metabolism of almitrine followed by rapid excretion of the metabolite in the bile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558129
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  • 153
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    Electronic Resource
    The pharmacokinetics of clotiazepam after oral and sublingual administration to volunteers (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 617-619 
    Details
    ISSN: 1432-1041
    Keywords: clotiazepam ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the single dose pharmacokinetics of 5 mg clotiazepam drops, oral tablets, and sublingual tablets in a cross-over study in 6 healthy volunteers (median age 28 years). The formulations had similar systemic availability. Compared with oral tablets the sublingual route gave a lower peak concentration and a delayed peak time, while drops gave a greater maximum concentration with a similar peak time. The use of drops is suggested for a more marked initial effect and the sublingual route for easier administration, especially in the elderly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562556
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  • 154
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    Electronic Resource
    Lack of effect of ponsinomycin on the plasma pharmacokinetics of theophylline (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 101-104 
    Details
    ISSN: 1432-1041
    Keywords: theophylline ; ponsinomycin ; pharmacokinetics ; drug interactions ; macrolide antibiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of ponsinomycin on the pharmacokinetics of theophylline has been studied in 12 young healthy volunteers. They received 10 doses of theophylline 200 mg every 8 h p.o., successively in the absence and then in the presence of ponsinomycin. This new macrolide, structurally related to midecamycin, was given in the therapeutic dose of 800 mg b.d. for 5 days, starting 2 days before the second phase of treatment with theophylline. The pharmacokinetic parameters of theophylline, calculated from its plasma concentration at steady-state, were not affected by the co-treatment. In particular, there was no significant difference between the peak and trough plasma levels, apparent clearance or apparent elimination half-life of theophylline in the absence and the presence of ponsinomycin. Only renal clearance was slightly (27%) but significantly increased by the co-treatment. The results suggest that ponsinomycin would be a good choice if a macrolide antibiotic were needed in patients being treated with theophylline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609435
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  • 155
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    Electronic Resource
    The pharmacokinetics of amiloride-hydrochlorothiazide combination in the young and elderly (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 167-171 
    Details
    ISSN: 1432-1041
    Keywords: amiloride ; hydrochlorothiazide ; pharmacokinetics ; steady-state ; elderly ; fixed combination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of amiloride and hydrochlorothiazide were studied in 12 healthy young volunteers following a single dose of a fixed combination of amiloride and hydrochlorothiazide and in 11 elderly hypertensive patients at steady-state. Following modelling of the single dose data, simulated steady-state plasma concentrations for the 2 drugs were generated to examine the effect of age and/or hypertension on pharmacokinetics. The apparent systemic plasma clearance for both amiloride and hydrochlorothiazide was significantly reduced in the elderly when compared to the young (from 753 to 325 ml·min−1, amiloride; and from 418 to 157 ml·min−1, hydrochlorothiazide). The plasma concentrations at steady state for both drugs were greatly increased in the elderly patients (Amiloride: from 7 to 25 ng·ml−1, Css,max; from 2 to 8 ng·ml−1, Css,min; and from 4 to 14 ng·ml−1, Cav; Hydrochlorothiazide: from 184 to 651 ng·ml−1, Css,max; from 31 to 121 ng·ml−1, Css,min; and from 89 to 273 ng·ml−1, Cav). The decreased clearance of the diuretics in the elderly was believed due to deterioration of renal function, and there was a significant correlation between the plasma clearance of hydrochlorothiazide and creatinine clearance in both age groups (r=0.62, young;r=0.72, elderly). As a result of the pharmacokinetic findings caution may be indicated in the clinical dosage of the diuretics particularly when in fixed dose combination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558226
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  • 156
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    Electronic Resource
    Haemodynamic effects and pharmacokinetics of felodipine at rest and during exercise in hypertensive patients treated with metoprolol or atenolol (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 459-465 
    Details
    ISSN: 1432-1041
    Keywords: felodipine ; metoprolol ; atenolol ; hypertension ; exercise ; pharmacokinetics ; adverse effects ; hypotensive action
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A study has been performed in thirteen patients with essential hypertension, WHO Class I–II, and a diastolic blood pressure ≥95 mm Hg, on beta-blocker (metoprolol or atenolol) monotherapy, who were also given felodipine 10 mg b.d. for 28 days. The acute and steady state blood pressure response at rest and during exercise, and the pharmacokinetics of felodipine and metoprolol, were examined. Felodipine in combination with the beta-blocker reduced the systolic and diastolic blood pressures acutely and at steady-state. The duration of the effect was longer at steady-state. There was a significant correlation between the plasma concentration of felodipine and the change in blood pressure. The increase in systolic blood pressure during exercise was of the same magnitude before and after felodipine administration. No change in resting supine heart rate was found after the administration of felodipine. There were no significant differences in the pharmacokinetics of felodipine during long-term treatment, except for the trough plasma concentration, which was increased at steady-state, even though cumulation of felodipine and its metabolite did not occur. There was a significant decrease in the maximal plasma concentration and AUC of metoprolol after 28 days of treatment with felodipine, but its elimination half-life was not changed. The adverse reactions reported during this study were those generally seen after dihydropyridines and, except for two patients who were withdrawn after the first study day, the effects were well tolerated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558124
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  • 157
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    Pharmacokinetics of 6-thiouric acid and 6-mercaptopurine in renal allograft recipients after oral administration of azathioprine (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 265-271 
    Details
    ISSN: 1432-1041
    Keywords: azathioprine ; 6-thiouric acid ; 6-mercaptopurine ; renal transplantation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The immunosuppressive activity of azathioprine (AZA) is unpredictable and depends on the formation of intracellular thiopurine ribonucleotides. However, the quantification of these active thiopurines presents difficult analytical problems. It has recently been postulated that plasma concentrations of 6-thiouric acid (6-TU) and 6-mercaptopurine (6-MP), metabolites of AZA, may provide more readily measurable indices of the pharmacologic activity of AZA. In order to evaluate the utility of 6-TU and 6-MP plasma concentrations in monitoring AZA therapy, we studied their pharmacokinetics in 6 renal transplant patients, and their in vitro immunosuppressive potency in a mixed lymphocyte proliferation assay. A peak plasma 6-TU concentration of 710.7 ng/ml was observed at 3.8 h after oral dosing. Good correlation was observed between the elimination t1/2 of 6-TU and serum creatinine, and between AUC over 24 h and serum creatinine. However, we did not observe a second peak in plasma 6-TU concentration that could be attributed to the degradation of active AZA metabolites. 6-MP plasma concentrations in the patients were low (mean peak concentration 36.0 ng/ml) and rapidly disappeared within 8 h. In vitro immunosuppressive activity could not be demonstrated for 6-TU over a concentration range of 1.25 ng/ml to 0.25 mg/ml. We conclude that 6-TU is pharmacologically inert and is primarily eliminated by the kidneys. Our findings currently do not support the use of plasma concentrations of 6-TU or 6-MP to monitor AZA therapy. In order to optimize AZA therapy, analytical techniques that are technically feasible and that can directly quantify the active intracellular thiopurines are being explored.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558158
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  • 158
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    Electronic Resource
    The disposition of meptazinol after single and multiple intravenous administration to pregnant and non-pregnant women (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 273-277 
    Details
    ISSN: 1432-1041
    Keywords: meptazinol ; pregnant and non-pregnant women ; pharmacokinetics ; single and repeated i.v. dosing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the disposition of the centrally-acting analgesic meptazinol in a group of age-matched non-pregnant and pregnant (36–38 weeks gestation) women. Ten non-pregnant and nine multiparous pregnant volunteers each received a single i.v. dose of meptazinol hydrochloride (equivalent to 25 mg base). A further group of 9 non-pregnant (including four of the original participants) and 10 multiparous pregnant subjects were given repeated i.v. doses of meptazinol hydrochloride (each equivalent to 10 mg base) at 30-min intervals for 2.5 h. Meptazinol plasma concentrations were determined by HPLC using fluorescence detection and the pharmacokinetic variables investigated. After single dosing there were no statistical differences in half-life, clearance, or apparent volume of distribution between the two groups, suggesting that the disposition of meptazinol was not altered by pregnancy. This was confirmed in the repeated dose study, in which no significant differences occurred in either the plasma concentrations achieved or in areas under the curves between the non-pregnant and pregnant subjects. Furthermore, the steady-state concentrations were comparable with those predicted from the single dose results. This indicates that there should be no requirement for dosage alteration of meptazinol during pregnancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558159
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  • 159
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    The systemic availability of meptazinol in man after oral and rectal doses (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 279-282 
    Details
    ISSN: 1432-1041
    Keywords: meptazinol ; rectal and oral administration ; pharmacokinetics ; first-pass metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the pharmacokinetics of the centrally-acting analgesic meptazinol after oral and rectal administration to 15 healthy men. Each subject took a standard 200 mg tablet orally and Witepsol H12 suppositories containing 75, 100, and 150 mg of the drug in a cross-over design. Meptazinol plasma concentrations were measured by HPLC using fluorescence detection and the pharmacokinetics determined. The tmax values for the 100 mg and 150 mg suppositories (median =0.5 h) were statistically significantly shorter than for the tablet (median =1.13 h), suggesting that meptazinol was more rapidly absorbed via the rectal route. Despite substantial intersubject variation in Cmax the plasma concentrations after rectal dosage were higher than after oral administration. There was a statistically significant (p〈0.001) improvement in systemic availability for each of the suppository doses (mean approximately 15.5% compared with the oral tablet (mean approximately 4.5%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558160
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  • 160
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    Stereoselective plasma protein binding of ibuprofen enantiomers (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 283-290 
    Details
    ISSN: 1432-1041
    Keywords: ibuprofen ; enantiomers ; stereoselective protein binding ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have developed a novel and reproducible method for determining the plasma protein binding of the two ibuprofen enantiomers in the presence of each other. The method involves the use of radiolabelled racemic ibuprofen, equilibrium dialysis, derivatization of the enantiomers to diastereomeric amides, high-performance liquid chromatography, and radiochemical analysis. We have determined the plasma protein binding of R(−)- and S(+)-ibuprofen in 6 healthy male volunteers after the oral administration of 800 mg racemic ibuprofen. The mean time-averaged percentage unbound of the R(−)-enantiomer, 0.419 was significantly less than that of the S(+)-enantiomer, 0.643, consistent with stereoselective plasma protein binding. The percentage unbound of each ibuprofen enantiomer was concentration-dependent over the therapeutic concentration range and was influenced by the presence of its optical antipode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558161
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  • 161
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    Inhibitory effect of enoxacin, ofloxacin and norfloxacin on renal excretion of theophylline in humans (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 323-324 
    Details
    ISSN: 1432-1041
    Keywords: theophylline ; fluoroquinolones ; drug interaction ; renal excretion ; pharmacokinetics ; clearance ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558168
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  • 162
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    Influence of a very low calorie diet on the clearance of oxazepam and antipyrine in man (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 407-409 
    Details
    ISSN: 1432-1041
    Keywords: oxazepam ; antipyrine ; glucuronidation ; drug metabolism ; very low calorie diet ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A very low calorie diet (Prodi) was administered to eleven otherwise healthy obese subjects for fourteen days. The daily intake of protein was 52.7 g and carbohydrate 25.7 g, corresponding to 360 kcal. The clearance of oxazepam and antipyrine was investigated before and after the diet period. Total oxazepam clearance was 1.04 ml·min−1·kg−1 and it decreased 0.88-fold after the diet. The mean clearance of unbound oxazepam was correspondingly reduced 0.88-fold. The elimination half-life increased to 1.22-times the control value, 7.9 h. No significant change was found in the volume of distribution or protein binding of oxazepam. Antipyrine clearance, estimated by the one-sample technique, was 52.4 and 51.8 ml·min−1, before and after the diet, respectively. It appears that a very low calorie diet with a sufficient protein and a very low carbohydrate content decreases the metabolism of oxazepam by glucuro-conjugation, whereas no effect was seen on the oxidative metabolism of antipyrine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558304
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  • 163
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    Pharmacokinetics of nitrendipine in terminal renal failure (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 467-471 
    Details
    ISSN: 1432-1041
    Keywords: nitrendipine ; renal failure ; pharmacokinetics ; protein binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and plasma protein binding of nitrendipine in patients with terminal renal failure have been compared with those in subjects with normal renal function. Kinetic parameters were calculated after a single 40 mg oral dose, an i.v. injection of 3 mg and after a 15 mg i.v. infusion of nitrendipine. Steady-state plasma levels were determined after 5 days of oral treatment with 20 mg b.d. Pharmacokinetic parameters and steady-state plasma levels in patients with renal failure did not differ from those in subjects with normal renal function. Nitrendipine was as highly bound to plasma proteins in patients with renal failure, as in subjects with normal renal function. The plasma protein did not differ between the two. The dosage of nitrendipine need not be modified for kinetic reasons in patients with renal failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558071
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  • 164
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    Pharmacokinetics of felodipine in patients with liver disease (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 473-479 
    Details
    ISSN: 1432-1041
    Keywords: felodipine ; liver cirrhosis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nine patients (6 males, 3 females) with biopsy-proven liver cirrhosis participated in an open, cross-over, three centre study of the effect of impaired liver function on the pharmacokinetics of felodipine. Two of the nine patients had undergone porto-caval anastomosis. Each patient was given 0.75 mg i.v. and 10 mg p.o. on separate occasions. The results of this study have been compared with published data from younger subjects and elderly hypertensive patients. The mean peak plasma concentration normalized to a dose of 10 mg (Cmax 46 nmol/l) was twice as high in the cirrhotic patients as in the healthy subjects, but the bioavailability, f, (17.0%) was comparable. Subjects with a porto-caval shunt did not have higher f than the mean for the group. The volume of distribution at steady-state, Vss, was significantly lower than in the healthy subjects. Protein binding was significantly lower in the patients with cirrhosis: 99.46% compared to 99.64% in the healthy subjects. The weight-corrected clearance was 1/3 of the value in healthy subjects. No correlation between systemic availability and oral clearance was found, so it is proposed that felodipine is metabolized both in the liver and also in the gut wall. The results suggest that at least the starting dose should be reduced in patients with severe liver disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558072
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  • 165
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    Felodipine reduces the absorption of theophylline in man (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 481-485 
    Details
    ISSN: 1432-1041
    Keywords: felodipine ; theophylline ; absorption ; metabolism ; pharmacokinetics ; blood pressure ; side-effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Ten healthy male volunteers (mean age 26 years) received 200 mg theophylline aminopropanol orally 8-hourly for 4 days, followed by 5 mg felodipine 8-hourly for 6 days, and then the combination of oral felodipine and theophylline for a further 4 days. Plasma concentrations of theophylline and felodipine were determined, and theophylline and its metabolites in urine were also measured. Felodipine led to a reduction in the plasma AUC of theophylline of 18.3%. The metabolic and renal clearances of theophylline remained unchanged, but the total recovery of theophylline-derived products was significantly reduced during felodipine treatment. No change in felodipine pharmacokinetics was observed during simultaneous treatment with theophylline. Compared to theophylline treatment alone, the diastolic blood pressure was significantly reduced during felodipine treatment alone and in combination with theophylline. It is concluded that felodipine slightly but significantly lowered the plasma theophylline concentration by interfering with its absorption. The interaction in most instances would probably be of minor clinical consequence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558073
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  • 166
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    Tolerability and steady-state pharmacokinetics of terodiline and its main metabolites in elderly patients with urinary incontinence (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 487-493 
    Details
    ISSN: 1432-1041
    Keywords: terodiline ; elderly patients ; metabolites ; pharmacokinetics ; side-effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The elderly form an important target group for the treatment of urinary urge incontinence with drugs such as terodiline (Mictrol, Terolin). In order to evaluate its steady-state pharmacokinetics and tolerability in geriatric patients terodiline 12.5 mg b.d. was given to 28 hospitalized patients with urinary incontinence (mean age 85 years) for six weeks. The patients were monitored during the study and for 6 weeks afterwards, blood samples being taken at regular intervals. In addition to these multi-diseased and polymedicated patients, a small, homogenous group of healthy volunteers (mean age 40 years) was studied as a reference group, being given terodiline 12.5 mg b.d. for 2 weeks. Terodiline was generally well tolerated by the patients and no significant change in blood pressure or heart rate were found. One patient was withdrawn due to adverse effects. The mean terminal half-life of terodiline was 131 h and the clearance after oral administration (clearance/systemic availability) was 39 ml·min−1. The corresponding figures for the healthy volunteers were 57 h and 75 ml·min−1. The average steady-state serum concentration was 518 µg·l−1 in the geriatric patients and 238 µg·l−1 in the healthy volunteers. Steady-state was reached within 3 weeks in 20 of the 28 patients and within 5 weeks in 7 patients. In the geriatric patients the steady-state serum concentration of the main metabolite p-hydroxyterodiline, during the last three weeks on terodiline was 45 µg·l−1, 57 µg·l−1, and 45 µg·l−1, respectively, and a similar value was found in the healthy volunteers, 47 µg·l−1. The serum concentration of p-hydroxy-m-methoxyterodiline was 〈15 µg·l−1 both in the geriatric patients and in the healthy volunteers. Thus, terodiline 25 mg/day given to fragile elderly patients was well tolerated. It produced serum concentrations similar to those found after the standard dose of 37.5–50 mg given to younger, healthier patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558074
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  • 167
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    Pharmacokinetic interaction between indomethacin and diflunisal (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 507-512 
    Details
    ISSN: 1432-1041
    Keywords: indomethacin ; diflunisal ; drug interaction ; glucuronidation ; pharmacokinetics ; faecal blood loss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of treatment with diflunisal on the steady-state pharmacokinetics of indomethacin has been studied in 16 healthy volunteers. The steady-state plasma concentration and AUC of indomethacin were significantly increased two- to threefold during treatment with diflunisal and its total clearance and total volume of distribution were significantly decreased. The urinary recovery of total indomethacin (unchanged+glucuronides) was significantly lower during administration of diflunisal, whereas excretion of the indomethacin metabolites desmethylindomethacin and desbenzoylindomethacin and their glucuronides was not significantly altered. The results can be explained by selective inhibition of glucuronidation of unchanged indomethacin by diflunisal. The interaction appears clinically relevant as potentially dangerous side effects of indomethacin are related to its plasma concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558077
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  • 168
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    Effect of age on the pharmacokinetics of dipyrone (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 513-516 
    Details
    ISSN: 1432-1041
    Keywords: dipyrone ; methylaminoantipyrine ; aging ; renal function ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of the dipyrone metabolite, 4-metylaminoantipyrine (MAA) was evaluated, following the administration of a single oral dose of dipyrone 1.0 g to 12 young (21–30 years) and 9 elderly (73–90 years) healthy volunteers. Maximal concentration, time to peak and absorption rate of MAA were similar for both groups. The elimination half-life was 2.6 (0.2) h for the young and 4.5 (0.5) h for the elderly subjects. Total clearance of MAA, corrected for lean body mass (LBM), was lower in the elderly than in the young 2.65 vs 3.97 ml·min−1·k−1 LBM. There was no differences between the groups in the apparent volume of distribution. A good correlation was found between the total body clearance of MAA and the creatinine clearance, which was also reduced in the elderly (r=0.61).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558078
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  • 169
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    Pharmacokinetics, efficacy and adverse effects of sublingual salbutamol in Patients with asthma (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 567-571 
    Details
    ISSN: 1432-1041
    Keywords: salbutamol ; sublingual ; oral ; inhaled ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Administration of drugs by the sublingual route provides rapid systemic absorption and avoids first-pass metabolism. The purpose of the present study was to assess the pharmacokinetics, efficacy and adverse effects of standard salbutamol tablets given by this route to patients with asthma. Seven asthmatic patients were given either sublingual salbutamol tablet 2 mg (SL), swallowed tablet 2 mg (O), metered dose inhaler 200 µg (MDI) or placebo (PL), in a randomized single-blind cross-over design. Airways responses (FEV1, FVC, PEFR), finger tremor (Tr), heart rate (HR), plasma potassium (K) and plasma salbutamol were measured over a 6 h period following drug administration. There were highly significant changes in FEV1 with MDI, O and SL routes compared with PL, although the response to MDI was greater and more rapid than with O or SL. There were similar findings for FVC and PEFR responses. There were no adverse effects with MDI, whereas both 0 and SL produced significant tremor responses. There were no differences between O and SL for any of the pharmacodynamic parameters. In addition, pharmacokinetic profiles for O and SL were also similar apart from an initial delay in absorption with SL. There were however, no significant differences in any of the pharmacokinetic parameters, between O and SL. This suggests that buccal absorption of salbutamol was negligible, and that systemic absorption occurred after swallowing of the dissolved sublingual tablet. These results show that sublingual administration of salbutamol tablet has no clinical benefit over the oral route.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562546
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  • 170
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    Penetration of cefoperazone into ascites (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 577-580 
    Details
    ISSN: 1432-1041
    Keywords: cefoperazone ; cirrhosis ; ascites ; pharmacokinetics ; ascitic fluid content
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of cefoperazone was studied in eleven cirrhotic patients with ascites after i.v. administration of a single dose of 15 mg·kg−1 (n=7) or after three doses of 15 mg·kg−1 given at 12 h intervals (n=4). The concentrations of cefoperazone in serum and ascitic fluid were determined by HPLC. The peak serum cefoperazone concentration after a single i.v. injection of 15 mg·kg−1 was 96.0 mg·l−1. The serum elimination half-life was longer (5.0 h) than in normal subjects. The penetration of cefoperazone into ascites was satisfactory (32.3% and 58.3% after single and repeated injections, respectively). Ascitic fluid concentrations of cefoperazone exceeded 5.4 mg·ml−1 from 0.5 to 6 h after the single i.v. injection, levels which are well above the MIC of most pathogens found in spontaneous bacterial peritonitis. Adjustment of the dose of cefoperazone in cases of severe hepatic insufficiency does not appear to be necessary provided that renal function is normal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562548
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  • 171
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    Non-linear kinetics of 4-methylpyrazole in healthy human subjects (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 599-604 
    Details
    ISSN: 1432-1041
    Keywords: 4-methylpyrazole ; alcohol dehydrogenase inhibitor ; healthy volunteers ; pharmacokinetics ; saturable kinetics ; zero order elimination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In order to evaluate the pharmacokinetic profile of the alcohol dehydrogenase inhibitor 4-methylpyrazole 4-MP, a placebo-controlled, double-blind, single-dose, randomized, sequential, ascending-dose “Phase-I study” was performed in healthy male volunteers at dose levels of 10 (n=4), 20 (n=4), 50 (n=4) and 100 mg·kg−1 (n=3). In the 10 and 20 mg·kg−1 group, the elimination of 4-MP from the plasma followed non-linear kinetics with mean rates of concentration decline of 3.66 and 5.05 µmol·1−1·h−1, respectively. In the two highest dose groups, the elimination also appeared to be non-linear although the patterns were not followed long enough to confirm this, The mean rates of concentration decline at the higher doses were significantly increased, up to 14.9 µmol·l−1·h−1 at 100 mg·kg−1. The average renal clearance of 4-MP was low, 0.016 ml·min−1·kg−1, and only 3% of the administered dose was excreted unchanged in the urine, indicating metabolism as the major route of elimination. Because of the apparently unusual kinetics following single dose treatment, thorough multiple dose studies need to be carried out to determine a safe dosage regimen for 4-MP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562552
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  • 172
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    Antipyrine metabolism is not affected by terbinafine, a new antifungal agent (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 231-233 
    Details
    ISSN: 1432-1041
    Keywords: antipyrine ; terbinafine ; drug metabolism ; drug interaction ; enzyme induction/inhibition ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The potential to inhibit drug metabolism of the new antifungal agent terbinafine has been studied using antipyrine (single oral dose of 10 mg/kg) as a probe drug. In a cross-over study in 8 healthy volunteers, antipyrine was administered prior to, during and after 8 days of oral terbinafine 125 mg b.d. Antipyrine, its major metabolites 4-hydroxyantipyrine (4-OH-AP), 3-hydroxymethylantipyrine (3-OH-CH3-AP) and norantipyrine (Nor-AP) were analyzed by specific HPLC assays in multiple plasma and urine samples. During all three parts of the study, the pharmacokinetics of antipyrine viz. t1/2 (11.7 h), total plasma (38.5 ml·h−1·kg−1) and renal clearance (1.6 ml·h−1·kg−1), and its clearance rates to metabolites (CLM), eg. CLM for 4-OH-AP (12.3 ml·h−1·kg−1), CLM for 3-OH-CH3-AP (4.2 ml·h−1·kg−1) and CLM for Nor-AP (6.7 ml·h−1·kg−1) did not differ from the control values. Thus, all the cytochrome P-450-dependent isozymes involved in the metabolism of antipyrine and many other drugs should not be affected by therapeutic doses of terbinafine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679775
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  • 173
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    Zolpidem excretion in breast milk (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 245-248 
    Details
    ISSN: 1432-1041
    Keywords: breast milk ; zolpidem ; pharmacokinetics ; imidazopyridine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Five, lactating, healthy white women were treated with a single 20 mg tablet of zolpidem 3–4 days after the delivery of a full term baby. The drug was administered at 20.00 h, 30 min after dinner, and milk samples were collected before and 3, 13 and 16 h. Venous blood 5 ml was taken before and 1.5, 3, 13, 16 h after zolpidem administration. The apparent elimination half life, estimated from plasma zolpidem concentrations was 2.6 h. The amount of zolpidem excreted in the milk at 3 h ranged between 0.76 and 3.88 µg, which represented 0.004 to 0.019% of the administered dose; no detectable (below 0.5 ng/ml) zolpidem was found in the milk at subsequent sampling times. The ratio of the zolpidem concentrations in breast milk and plasma at 3 h was 0.13. The apparent breast milk clearance of zolpidem, calculated from the ratio of the total amount of zolpidem excreted in milk to its AUC in plasma was 1.48 ml/h. The results show that the excretion of zolpidem in human milk is very low (below 0.02%) and that most of it takes place during the first 3 h following drug intake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679778
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  • 174
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    Oral pharmacokinetics and ascitic fluid penetration of ofloxacin in cirrhosis (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 261-265 
    Details
    ISSN: 1432-1041
    Keywords: oflaxacin ; ascitic fluid ; cirrhosis ; drug penetration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma and ascitic fluid concentrations of ofloxacin were determined in 12 cirrhotic patients after a single dose and repeated 200 mg oral doses. The single dose kinetics were compared to those obtained in 12 healthy volunteers. Mean plasma elimination half-life was 11.6 h in cirrhotics and 7.0 h in controls. Mean total clearance was 2.3 times lower in patients than in controls, due to a significant decrease of renal clearance of the drug, unrelated to creatinine clearance. Mean apparent volume of distribution was 1.2 l/kg in patients and 1.8 l/kg in controls. Estimated by the ratio of AUC in peritoneal fluid and plasma, ascitic fluid penetration was 80% after the first oral dose. Ascitic fluid concentrations equaled corresponding plasma concentrations after 10 h, without pronounced accumulation of ofloxacin in ascites. We may conclude that, in cirrhotic patients with normal serum creatinine, a significant impairment of renal tubular handling of ofloxacin could be observed and led to a delayed elimination half-life of the drug. Because of its broad sprectrum of activity, low side-effect profile, and large ascitic fluid penetration after oral administration, ofloxacin appears to be a new therapeutic approach of severe infections in cirrhotic patients, in particular spontaneous bacterial peritonitis.
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    URL: http://dx.doi.org/10.1007/BF00679781
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  • 175
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    The pharmacokinetics of midazolam in paediatric patients (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 267-272 
    Details
    ISSN: 1432-1041
    Keywords: midazolam ; pharmacokinetics ; children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A serum concentration profile study on midazolam in children was done. Fifty six children aged 3–10 years took part. The routes investigated were intravenous, intramuscular, rectal and oral at 0.15 mg·kg−1, and the oral at 0.45 mg·kg−1 and 1 mg·kg−1. Serum concentration levels for 5 h were studied using gas liquid chromatography. The volume of distribution, Vss, was 1.29 l·kg−1, the elimination half-life 1.17 h and the serum clearance 9.11 ml·kg−1·min−1. Peak serum concentrations for the intramuscular, rectal and oral routes were at 15 min, 30 min and 53 min respectively. Bioavailability was 87%, 18%, 27% respectively at a dose of 0.15 mg·kg−1. The oral route bioavailability halved to 15% at the two higher doses. Bioequivalence was present between the 0.15 mg·kg−1 intramuscular dose and the 0.45 mg·kg−1 oral dose from 45 to 120 min.
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    URL: http://dx.doi.org/10.1007/BF00679782
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  • 176
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    Transdermal delivery of nicotine in normal human volunteers: a single dose and multiple dose study (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 285-290 
    Details
    ISSN: 1432-1041
    Keywords: nicotine ; transdermal delivery ; dose proportionality ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of nicotine delivered by a transdermal delivery system (TDS) was investigated in two separate studies, (A) a dose proportionality study and (B) a multiple dose study. In the dose range of 15–60 mg nicotine, the AUC and Cmax values were proportional to the dose. The levels achieved were in the same range as reported in smokers, following absorption from nicotine chewing gum. The TDS used in the present study produced sustained levels of nicotine for 24 h. No significant accumulation of nicotine was evident as a result of multiple dose administration using a 30-mg nicotine patch. Absorption of nicotine from the TDS was 80–90% and the rate of delivery was similar during both studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679785
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  • 177
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    Electronic Resource
    Effect of urinary pH on the plasma and urinary kinetics of remoxipride in man (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 359-363 
    Details
    ISSN: 1432-1041
    Keywords: neuroleptics ; remoxipride ; pharmacokinetics ; urinary pH ; healthy volunteers ; overdose ; plasma prolactin ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of urinary pH on the plasma and urinary kinetics of remoxipride in man has been studied in an open crossover trial in ten healthy male volunteers. Ammonium chloride (urinary pH 5.2) and sodium hydrogen carbonate (urinary pH 7.8) were used as pretreatments on two occasions in randomized order. On each occasion remoxipride 50 mg solution was administered orally and plasma and urinary concentrations of the drug were determined by HPLC and plasma prolactin concentrations by RIA. Remoxipride was rapidly distributed in the body according to a one-compartment model. The mean plasma elimination half-life (t1/2) was 3.6 h in the ammonium chloride experiment and 6.2 h in the sodium hydrogen carbonate experiment. The mean plasma clearance of remoxipride was 141 and 89.9 ml·min−1 in the acidic and alkaline conditions, respectively, and the corresponding mean renal clearances were 58.5 ml·min−1 and 11.7 ml·min−1. The urinary excretion of remoxipride up to 72 h after drug administration was 43.1% and 12.3% following acidification and alkalinization, respectively. Remoxipride induced a similar rapid, transient elevation of plasma prolactin under both conditions. Thus, the urinary pH has a marked effect on the elimination kinetics of remoxipride. After an overdose, treatment with ammonium chloride might be valuable in hastening elimination of remoxipride from the body.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558500
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  • 178
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    Electronic Resource
    Increased theophylline clearance in asthmatic patients due to terbutaline (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 25-28 
    Details
    ISSN: 1432-1041
    Keywords: theophylline ; terbutaline ; asthma ; drug interaction ; hepatic metabolism ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic mechanism of the theophylline-terbutaline interaction has been studied. Sustained release theophylline 200–400 mg b.d. was given with placebo or terbutaline 2.5 mg t.d.s. to six adult asthmatic patients. Terbutaline decreased the serum trough theophylline levels from 8.1 to 7.3 µg/ml, improved daily the clinical score from 1.51 to 1.26 and increased the peak expiratory flow rate from 316 to 370 l/min. In a single dose study following the chronic therapy, it was shown that there was no change in the peak theophylline concentration or in the timing of the peak, but the t1/2 was reduced from 9.0 to 7.5 h, and the systemic clearance was increased from 20.2 to 24.8 ml·h−1·kg−1. Thus, terbutaline reduced the serum theophylline concentration by increasing its systemic clearance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561018
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  • 179
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    Electronic Resource
    Steady-state intravenous pharmacokinetics of pirenzepine in patients with hepatic insufficiency and combined renaland hepatic insufficiency (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 71-73 
    Details
    ISSN: 1432-1041
    Keywords: pirenzepine ; hepatic insufficiency ; hepato-renal insufficiency ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The steady-state intravenous pharmacokinetics of pirenzepine has been investigated in patients with chronic liver disease and others with combined chronic liver disease and renal sufficiency. The plasma clearance (CL) of Pirenzepine, steady-state plasma concentration Cmin(ss) and dominant half life t1/2γ were not significantly altered in the chronic liver disease group. In patients with renal and hepatic insufficiency, CL was reduced, t1/2γ was prolonged from 11.1 to 19.4 h and Cmin(ss) was elevated from 36 ng/ml to 66 ng/ml compared to healthy controls. Plasma concentrations remained in the therapeutic range and the dosage regimen was well tolerated. Adjustment of the dose of pirenzepine need be considered only in cases of severe impairment of both renal and hepatic elimination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561027
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  • 180
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    Electronic Resource
    Effect of diltiazem on the pharmacokinetics of propranolol, metoprolol and atenolol (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 67-70 
    Details
    ISSN: 1432-1041
    Keywords: diltiazem ; propranolol ; metoprolol ; atenolol ; pharmacokinetics ; drug interaction ; beta-adrenoceptor blockade ; healthy volunteers ; pharmacodynamic effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic interaction between diltiazem and three β-adrenoceptor blockers propranolol, metoprolol and atenolol was investigated in healthy volunteers given diltiazem 30 mg or placebo t.d.s. for 3 days, followed by a single dose of propranolol 20 mg, metoprolol 40 mg or atenolol 50 mg. The AUCs of propranolol and metoprolol were significantly increased after diltiazem and it significantly prolonged the elimination half-life of metoprolol. In contrast, it did not significantly affect the pharmacokinetics of atenolol. Propranolol significantly decreased the resting pulse rate after diltiazem pretreatment as compared to placebo. The results indicate that diltiazem impaired the clearance of propranolol and metoprolol, which are principally metabolized by an oxidative pathway, and that the kinetic interaction between diltiazem and propranolol may partly be related to the significant reduction in the pulse rate produced by the latter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561026
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  • 181
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    Electronic Resource
    Pharmacokinetics of cefonicid in children (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 79-82 
    Details
    ISSN: 1432-1041
    Keywords: cefonicid ; paediatric infections ; pharmacokinetics ; single dose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of cefonicid was studied in 17 children requiring antibiotic treatment for respiratory or urinary tract infections. After informed consent had been obtained from the parents, a single dose of cefonicid 50 mg/kg/body weight was given by intramuscular injection. The mean peak serum concentration of 212.63 µg/ml was reached at 1.00 h, as absorption occurred at a very fast rate with a mean constant of 3.24 h−1. Mean values for half-life, apparent volume of distribution (Vz), total body clearance (CL), and renal clearance (CLR) were 3.24 h, 0.21 l·kg−1, 16.67 ml·min−1 and 13.60 ml·min−1 respectively. There was an inverse relationship between age and Vz, whereas CL and CLR were positively correlated with age. Cefonicid concentrations in urine were many times higher than the MICs of susceptible strains of bacteria. The study demonstrated that i.m. cefonicid 50 mg·kg−1 gave serum concentrations well within the therapeutic range for susceptible bacteria, and that its pharmacokinetic properties allow single daily doses to be used to treat infections in children.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561029
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  • 182
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    Electronic Resource
    Chronopharmacology and its application to the development of theophylline treatment schedules for asthma (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 103-109 
    Details
    ISSN: 1432-1041
    Keywords: asthma ; chronopharmacology ; theophylline ; circadian rhythms ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609180
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  • 183
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    Electronic Resource
    Pharmacokinetics of amlodipine in renal impairment (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 205-208 
    Details
    ISSN: 1432-1041
    Keywords: amlodipine ; pharmacokinetics ; renal-impairment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Amlodipine was administered as 14 single 5-mg oral daily doses to 27 male subjects with renal function ranging from normal to haemodialysis-dependent. Blood specimens were obtained for measurement of plasma amlodipine concentrations for 24 h following the first dose, for 168 h following the final dose and during daily administration of amlodipine. Amlodipine was well tolerated. Renal impairment had little effect on the pharmacokinetics of amlodipine. The elimination half-life was of the order of 50 h, similar to previously reported values and did not vary with renal function. Steady-state pre-dose concentrations were observed after the ninth dose. Accumulation of amlodipine was not significantly different from that expected on theoretical grounds and did not significantly change with renal function. These results suggest that once daily administration of amlodipine is suitable for all degrees of renal function and that dosage adjustment is not necessary in renal impairment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609197
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  • 184
    Electronic Resource
    Electronic Resource
    Transcutaneous absorption of naproxen gel (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 209-211 
    Details
    ISSN: 1432-1041
    Keywords: naproxen ; transcutaneous absortion ; non-steroidal anti-inflammatory drug ; topical application ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of naproxen was studied in healthy volunteers after cutaneous application of gels containing 5 and 10% of the drug. Bioavailability was estimated from serum concentration and cumulative urinary metabolite excretion data, both determined up to 96 hours after drug administration. The mean bioavailability after the 10% gel was 1.1% (serum data) and 1.0% (urine data), and after the 5% gel it was 2.1% (serum data) and 1.8% (urine data). Despite the small amount of naproxen absorbed, a potential pharmacological effect, due to cutaneous accumulation of the drug following topical administration, may be suggested from the course of the serum concentration-time curves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609198
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  • 185
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    Electronic Resource
    Plasma concentrations and haemodynamic effects of nimodipine in patients resuscitated after cardiac arrest (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 327-333 
    Details
    ISSN: 1432-1041
    Keywords: nimodipine ; pharmacokinetics ; haemodynamics ; cardiopulmonary resuscitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary As the pharmacokinetics of a drug may be altered in haemodynamically compromised patients, the plasma concentrations and haemodynamic effects of the calcium entry blocker nimodipine have been examined in patients resuscitated after out-of-hospital cardiac arrest. In 7 patients nimodipine was infused at increasing rates up to 30 µg·kg−1·h−1. The plasma concentrations increased with increasing dose; at the highest dose a mean steady-state plasma concentration of 22.1 ng·ml−1 was obtained, and the mean plasma clearance was 1.4 l·kg−1·h−1. There were no marked changes in mean arterial blood pressure or heart rate. In 9 other patients nimodipine was given as a bolus infusion of 10 µg·kg−1 over 3 min, followed by a continuous infusion of 30 µg·kg−1·h−1. A mean steady-state plasma concentration of 17.6 ng·ml−1 was obtained and the mean plasma clearance was 1.9 l·kg−1·h−1. Heart rate did not change significantly, but the mean arterial blood pressure fell. The data indicate that in patients resuscitated after cardiac arrest, the pharmacokinetics of nimodipine are not markedly different from patients with other conditions, e.g. subarachnoid haemorrhage. However, if a loading dose is given to obtain a steady-state concentration sooner, there will be a fall in arterial blood pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558290
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  • 186
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    Electronic Resource
    Alteration by burn injury of the pharmacokinetics and pharmacodynamics of cimetidine in children (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 361-367 
    Details
    ISSN: 1432-1041
    Keywords: cimetidine ; burned children ; stress ulceration ; pharmacokinetics ; pharmacodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the mechanisms of the increased dosage requirements of the H2-receptor antagonist cimetidine in paediatric burned patients in a pharmacokinetic and pharmacodynamic study. Cimetidine (10–15 mg·kg−1) was given to 21 burned children and multiple blood samples were obtained for determination of plasma cimetidine concentrations and pharmacokinetic analysis. The relation of gastric pH to plasma cimetidine concentrations was studied in five of these children who had nasogastric tubes. In an additional four patients the effects of cimetidine on gastric pH were studied during a continuous infusion of cimetidine, which maintained steady-state plasma cimetidine concentrations above 0.5 µg·ml−1. The mean (SEM) clearance of cimetidine in burned children was 16.22 ml·kg−1 and cimetidine half-life was 1.06 h. The cimetidine clearance and half-life values were significantly higher in burned children compared with our previously reported values for normal adult patients, 8.2 ml·min·kg−1 and 2.21 h respectively. Endogenous creatinine clearance normalized to 70 kg in burned children was 190 ml·min−1. In burned children 41% of the dose of intact cimetidine was excreted during 8 h of the study compared with 45% excretion during 24 h in healthy adult controls previously reported. The correlation coefficient between creatinine and cimetidine clearances was 0.93 (r 2=0.85). The plasma concentration of cimetidine needed to increase gastric pH to ≥4.0 was ≥1.0 µg·ml−1, which contrasts with the value of 〉0.5 µg·ml−1 required for adult burned patients. These findings support the hypothesis that the higher dosage requirements of cimetidine in burned children is due both to enhanced elimination kinetics and to alterations in target organ sensitivity, requiring higher than normal plasma concentrations for the desired effect. In burned children Cimetidine should be given in higher doses and/or more frequently.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558296
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  • 187
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    Kinetics of oral and intravenous mexiletine: lack of effect of cimetidine and ranitidine (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 375-378 
    Details
    ISSN: 1432-1041
    Keywords: mexiletine ; cimetidine ; ranitidine ; pharmacokinetics ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of mexiletine, a Class I antiarrhythmic drug, was investigated in 6 healthy volunteers after single oral doses and 15 min intravenous infusions of 3 mg/kg. Cimetidine and ranitidine are commonly used H2-receptor antagonists, which interact adversely with many drugs, e.g. inhibition of the metabolism of Class I antiarrhythmics such as lidocaine and quinidine by cimetidine. To investigate the effects of the two drugs on the kinetics of mexiletine, cimetidine 800 mg·day−1 or ranitidine 600 mg·day−1 were administered orally for one week. Neither H2-receptor antagonist altered the distribution and elimination of mexiletine, nor did they affect its overall kinetics, or excretion of the metabolites para- and 4-OH-methylmexiletine after oral and intravenous administration of mexiletine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558298
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  • 188
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    Electronic Resource
    Pharmacokinetic properties and clinical efficacy of once-daily sustained-release naproxen (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 383-388 
    Details
    ISSN: 1432-1041
    Keywords: naproxen ; sustained-release formulation ; pharmacokinetics ; bioavailability ; efficacy ; tolerability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and clinical efficacy of a once-daily sustained-release formulation of naproxen (sodium salt) have been compared with those of conventional-release agents. In a single dose pharmacokinetic study, the rate of absorption of the sustained-release preparation was less than that of a conventional-release preparation but the extent of absorption was the same. As is the case with conventional-release naproxen, food decreased the rate but not the extent of absorption of the sustained-release formulation. On multiple dose administration for 7 days, the AUC and average concentrations of the sustained release preparation (1 g daily) were the same as those for conventional release preparations of naproxen sodium (250 mg four times daily) and naproxen free acid (500 mg daily). The conventional-release sodium salt was absorbed more quickly with no differences in bioavailability. A double-blind clinical comparison in patients with osteoarthritis showed the sustained-release preparation (1 g daily) to be equivalent in efficacy to conventional naproxen capsules (500 mg twice daily) but to have a significantly lower incidence of gastrointestinal side-effects. The results suggest that sustained-release naproxen sodium has potential for use as a once-daily treatment for inflammatory disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558300
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  • 189
    Electronic Resource
    Electronic Resource
    High haemodialysis clearance of ornidazole in the presence of a negligible renal clearance (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 389-393 
    Details
    ISSN: 1432-1041
    Keywords: ornidazole ; haemodialysis ; pharmacokinetics ; renal function ; metabolism ; urine concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of ornidazole was studied in 6 patients treated by haemodialysis and in 8 subjects with a creatinine clearance between 4 and 99 ml/min × 1.73 m2. Blood and urine collections were performed for 72 h after i.v. and oral administration of 1.0 g ornidazole. Total body clearance, half-life, volume of distribution and systemic availability were independent of renal function and did not differ from previously reported values in normal volunteers. The haemodialysis clearance of ornidazole was 〉100% higher than the total body clearance. The renal clearance of ornidazole accounted for less than 7% of the total body clearance. The percentage of the dose of ornidazole recovered in urine as parent compound or as the biologically active metabolites [α-(chloromethyl)-2 hydroxymethyl-5 nitroimidazole-1 ethanol and 3-(2 methyl-5 nitroimidazole-1-yl)1,2 propanediol] decreased linearly with decreasing renal function. Although the sum of those three compounds recovered in urine accounted for less than 10% of the total dose of ornidazole administered, they yielded therapeutic concentrations (〉4 µg/ml) in urine over 24 h after dosing. Due to the peculiar pharmacokinetic behaviour of ornidazole, i.e. high haemodialysis clearance in the absence of significant renal clearance, no dosage adjustment is necessary while renal function declines, but an increased dose is mandatory while patients are on dialysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558301
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  • 190
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of pyrazinamide and its metabolites in healthy subjects (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 395-400 
    Details
    ISSN: 1432-1041
    Keywords: pyrazinamide ; antituberculous chemotherapy ; pharmacokinetics ; xanthine oxidase ; microsomal deaminase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma and urine pharmacokinetic parameters of pyrazinamide and of its metabolites (pyrazinoic acid, 5-hydroxy-pyrazinamide, 5-hydroxy-pyrazinoic acid and pyrazinuric acid) have been studied after a single oral dose of pyrazinamide 27 mg · kg−1 in 9 healthy subjects. Pyrazinamide was rapidly absorbed (tmax ≤1 h) and showed a short distribution phase followed by an elimination phase of t1/2β=9.6 h. The close similarity of the apparent elimination rates of the metabolites led to a second trial of a single oral dose of pyrazinoic acid to evaluate the formation and elimination stages. The limiting factor was found to be the activity of a microsomal deamidase (pyrazinoic acid formation from pyrazinamide and 5-hydroxy-pyrazinoic acid formation from 5-hydroxy-pyrazinamide). In contrast, oxidation by xanthine oxidase occurred very rapidly (5-hydroxy-pyrazinamide formation and pyrazinoic acid catabolism to 5-hydroxy-pyrazinoic acid).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558302
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  • 191
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    The effects of food and dose on the oral systemic availability of itraconazole in healthy subjects (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 423-426 
    Details
    ISSN: 1432-1041
    Keywords: itraconazole ; antifungal drug ; pharmacokinetics ; systemic availability ; dose-dependency ; food effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the influence of food and dose (50, 100, 200 mg) on the oral systemic availability of the broad spectrum antifungal itraconazole and the pharmacokinetics after repeated dosing of 100 mg in six healthy volunteers. The relative systemic availability of itraconazole capsules compared with solution averaged 39.8% in the fasting state but 102% in the post-prandial state. Food did not significantly affect the tmax of the capsules. Itraconazole AUC at single doses of 50, 100, and 200 mg had a ratio of 0.3:1:2.7, and the steady-state AUC (0–24) after 15 days of 100 mg was five times the single-dose AUC. These findings suggest non-linear itraconazole pharmacokinetics in the range of therapeutically used doses. Furthermore, capsules should be given shortly after a meal to ensure optimal oral systemic availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558308
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  • 192
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    Elimination and haemodynamic effects of nitrendipine in patients with chronic renal failure (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 433-437 
    Details
    ISSN: 1432-1041
    Keywords: nitrendipine ; renal failure ; haemodynamic effects ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In sixteen patients with arterial hypertension and differing degrees of renal function the pharmacokinetics and haemodynamic effects of nitrendipine have been studied after treatment for 7 days. The AUC (0–24) and the elimination half-life of nitrendipine were significantly increased; the AUC (0–24) in patients with renal failure (median creatinine clearance 27.1 ml × min−1) was 196 ng × ml−1 × h compared to 97.8 ng × ml−1 × h in control subjects (median creatinine clearance 94.4 ml × min−1). The corresponding elimination half-lives were 13.5 h in renal failure and 4.4 h in the controls. The haemodynamic effects of nitrendipine were not enhanced in the patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558065
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  • 193
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    Pharmacokinetic characterization of the antiarrhythmic drug diprafenone in man (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 313-316 
    Details
    ISSN: 1432-1041
    Keywords: diprafenone ; pharmacokinetics ; bioavailability ; first-pass metabolism ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of the antiarrhythmic drug diprafenone have been investigated in 6 healthy volunteers following single intravenous (50 mg) and oral doses (50 and 150 mg). Diprafenone was mainly eliminated by metabolism in the liver. Following i.v. infusion of 50 mg diprafenone, the terminal half-life of elimination was 1.50 h, the volume of distribution at steady-state was 1.23 l·kg−1, and the free fraction in plasma was 1.68%. Mean total plasma clearance was 741 ml·min−1·70 kg−1, which approaches normal liver blood flow after correction for the blood/plasma concentration ratio. Thus, diprafenone can be classified as a high extraction drug. Following oral administration, a dose-dependent increase in bioavailability from 10.9 (50 mg dose) to 32.5% (150 mg dose) was observed. The data suggest that diprafenone is subject to saturable hepatic first-pass metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679792
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  • 194
    Electronic Resource
    Electronic Resource
    Penetration of cyclosporin into synovial fluid in rheumatoid arthritis (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 321-322 
    Details
    ISSN: 1432-1041
    Keywords: cyclosporin ; synovial fluid ; rheumatoid arthritis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679794
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  • 195
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    Electronic Resource
    Pharmacokinetics of intravenous salbutamol in renal insufficiency and its biological effects (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 387-389 
    Details
    ISSN: 1432-1041
    Keywords: salbutamol ; pharmacokinetics ; renal insufficiency ; biological effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Salbutamol was administered intravenously to 5 patients with renal function impairment for estimation its pharmacokinetic parameters. The mean terminal half-life was 256 min, similar to previously reported values in healthy adults. The mean clearance (167 ml/min) and the mean volume of distribution (55 l) were decreased. These parameters were not correlated with the creatinine clearance. A slight but significant decrease was observed in the plasma potassium level up to 125 min after the salbutamol infusion. The heart rate was significantly increased, and the increase in 3 patients was correlated with the salbutamol concentration. The biological effects of the drug were less marked than expected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558505
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  • 196
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    The pharmacokinetics of ceftriaxone and cefotaxime in cirrhotic patients with ascites (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 613-616 
    Details
    ISSN: 1432-1041
    Keywords: ceftriaxone ; cefotaxime ; cirrhosis ; pharmacokinetics ; ascites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have compared in two separate studies the kinetics of ceftriaxone and cefotaxime in 8 cirrhotic patients with ascites and 8 control subjects after a single 20 min intravenous infusion of 1 g of each drug. The apparent volumes of distribution (Vz) were found to be significantly higher in cirrhotics than in control subjects (0.87, versus 0.49, l·kg−1, for cefotaxime and 0.23 versus 0.13 for ceftriaxone). The elimination kinetics of ceftriaxone were similar in the two groups. In contrast, the total and non-renal clearances of cefotaxime were reduced in cirrhotic patients. The two drugs rapidly entered the ascitic fluid. Peritoneal concentrations of ceftriaxone were higher than 7 µg·ml−1 from the second hour after the infusion and were 8.9 µg·ml−1 at 24 h. Peritoneal concentrations of cefotaxime were higher than 4 µg·ml−1 from 0.5 to 8 h after the infusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637745
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  • 197
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    Electronic Resource
    Influence of chronic diflunisal treatment on the plasma levels, metabolism and excretion of indomethacin (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 7-15 
    Details
    ISSN: 1432-1041
    Keywords: indomethacin ; diflunisal ; pharmacokinetics ; drug interaction ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The single-dose pharmacokinetics of indomethacin following 100 mg rectally was measured in two groups of 8 healthy subjects before and after diflunisal 500 mg p.o. once daily, or 500 mg in the morning and 1000 mg in the evening, until steady state conditions were reached. A further group of 8 healthy subjects was given 50 mg indomethacin rectally before and after diflunisal 500 mg p.o. twice daily. High dose diflunisal (1500 mg/day) decreased the renal clearance of indomethacin from 21.9 to 1.8 ml/min (92%) and reduced the renal excretion of both unchanged (63%) and conjugated (82%) indomethacin. The apparent total body clearance (0.12 l/h/kg), apparent volume of distribution (0.98 l/kg), and volume of distribution at steady state (0.80 l/kg) were decreased by 47%, 35% and 30%. The maximum plasma concentration (2.4 µg/ml) and total area under the curve (13.0 µg × h/ml) were increased by 40% and 119%, respectively. The terminal elimination half-life (5.7 h) and mean residence time (6.7 h) were slightly prolonged (7.0 h and 8.8 h) in the presence of diflunisal. The contribution of metabolism to the overall elimination of indomethacin was increased by only 2%. Similar results were obtained when the subjects were challenged with the low dose of diflunisal (500 mg/day), although the magnitude of the changes were smaller. The interaction between indomethacin and diflunisal may be due to competition both at the metabolic (conjugation) and the excretory (tubular secretion) levels. When the subjects were given 50 mg indomethacin and diflunisal 1000 mg/day simultaneously, the achieved maximum plasma concentration of indomethacin (2.53 µg/ml) was comparable to that seen after 100 mg in the absence of diflunisal (3.1 µg/ml), but the AUC was greater (21.7 µg × h/ml vs 13.0 µg × h/ml). Adverse central nervous reactions were more frequent and more pronounced at higher plasma indomethacin concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609416
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  • 198
    Electronic Resource
    Electronic Resource
    Amitriptyline: linear or nonlinear kinetics in every day practice? (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 595-598 
    Details
    ISSN: 1432-1041
    Keywords: amitriptyline ; nortriptyline ; pharmacokinetics ; linear kinetics ; depressed patients ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The linearity of the (AMT) kinetics of amitriptyline has been tested in 135 depressed dosed twice daily by measuring plasma. Their (AMT) and nortriptyline (NT) levels under steady-state conditions. The AMT concentration/dose ratios at low and high dosages were not significantly different and there was a linear relationship between the dose ratios and the concentration ratios. No change in the metabolic ratio (AMT/NT) was observed between the two dosages. Although the results are consistent with linear AMT kinetics, there may have been nonlinear kinetics in some patients as the ratio between the concentration/dose ratios in them at low and high dosages was greater than one. Those patients were characterized by a low concentration/dose ratio at low dosage. No clinical adverse effect appeared in the study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562551
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  • 199
    Electronic Resource
    Electronic Resource
    Sex-related differences in theophylline pharmacokinetics (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 97-100 
    Details
    ISSN: 1432-1041
    Keywords: theophylline ; sex differences ; pharmacokinetics ; gender
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Theophylline pharmacokinetic parameters were compared in healthy males and healthy premenopausal females who were matched for age and smoking status. Twenty-four subjects (including five smokers and seven non-smokers of each sex) received a single dose of aminophylline 6 mg·kg−1, orally or by intravenous infusion. Theophylline half-life was significantly shorter in female non-smokers (FNS) versus male non-smokers (MNS), (FNS=6.0 h; MNS=9.3 h), and in female smokers (FS) versus male smokers (MS), (FS=4.6 h; MS=6.3 h). Total body clearance was significantly different in FNS versus MNS, (FNS=43.8 ml·min−1·−1.73 m−2; MNS=37.4 ml·min−1·1.73 m−2), but did not reach statistical significance in FS vs. MS, (FS=64.2 ml·min−1·l−1·1.73 m−2; MS=53.1 ml·min−1·1.73 m−2). Volume of distribution did not differ significantly between groups. Sex differences in theophylline pharmacokinetics exist and may reflect differences in drug metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609434
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  • 200
    Electronic Resource
    Electronic Resource
    Pharmacokinetics and effects of frusemide in patients with the nephrotic syndrome (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 173-180 
    Details
    ISSN: 1432-1041
    Keywords: frusemide ; nephrotic syndrome ; albumin ; dextran ; pharmacokinetics ; renin-angiotensin-aldosterone system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The renal handling and effects of an intravenous bolus of frusemide with and without plasma volume expansion with dextran or albumin, and with large variations in plasma albumin concentration, have been studied in five patients with the nephrotic syndrome. Decreased renal sensitivity to frusemide was found in only one patient, who also had hypovolaemia and an activated renin-angiotensin-aldosterone system. Plasma volume expansion increased the diuresis but not the saluresis, and slightly increased renal sensitivity to frusemide. An increase in albuminuria after albumin infusion did not reduce the sensitivity to frusemide. A decrease in plasma albumin concentration from 33 g·l−1 after albumin infusion to 23 g·l−1 after infusion of dextran caused a substantial increase in the renal clearance (from 84 to 123 ml·min−1), non-renal clearance (from 72 to 138 ml·min−1), and apparent volume of distribution (from 13 to 23 l) of frusemide, probably as a consequence of an increase in the unbound fraction. The rate of urinary excretion of frusemide was highest after albumin infusion, despite the fact that its renal clearance was lowest then.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558227
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