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  • 1
    Electronic Resource
    Electronic Resource
    Selective INEPT as an NMR tool for studying repeat unit distribution and stereosequences in poly(.beta.-malic acid) copolymers (1992)
    s.l. : American Chemical Society
    Macromolecules 25 (1992), S. 143-148 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00027a024
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  • 2
    Electronic Resource
    Electronic Resource
    Natural poly(L-malic acid): NMR shows a poly(3-hydroxy acid)-type structure (1993)
    s.l. : American Chemical Society
    Macromolecules 26 (1993), S. 4681-4684 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00069a041
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  • 3
    Electronic Resource
    Electronic Resource
    Poly(β-3-methylmalic acid): A new degradable functional polyester with two stereogenic centers in the main chain (1994)
    Springer
    Polymer bulletin 33 (1994), S. 149-158 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Racemic ((3S,4R)-(3R,4S))-3-methyl-4-benzyloxycarbonyl-2-oxetanone has been prepared by a simple and reproductible method starting from a racemic mixture of threo-((2S,3S)-(2R,3R))-3-methylaspartic acid as chiral precursor. This α, β substituted β-lactone has been polymerized anionically, using tetraethylammonium benzoate as initiator, to yield high molecular weight and amorphous racemic threo-poly(β-benzyl-3-methylmalate). The catalytic cleavage of protecting benzyl ester groups has been conducted in different solvents and racemic threo-poly(β-3-methylmalic acid) has been obtained in N-methylpyrrolidone at room temperature. Racemic threo-poly(β-3-methylmalic acid-co-benzyl-β-3-methylmalate) has been prepared by heterogeneous H2/Pd charchoal catalyzed partial hydrogenolysis of the polymer precursor. Solubility of these different materials has been considered. Hydrolysis of threo-poly(β-3-methylmalic acid) has conducted to racemic threo-3-methylmalic acid. High resolution 13C NMR and selective INEPT NMR have been used for resonances assignment of polymers and copolymers. This new poly(β-hydroxy acid) type polyester expands the family of poly(β-malic acid) derivatives by opening the route for tailor making functional polystereoisomers with two stereogenic centers in the main chain and with the presence of an hydrophobic alkyl group and an hydrophilic carboxylic acid group in the macromolecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297349
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  • 4
    Electronic Resource
    Electronic Resource
    Simultaneous quantitative measurement of a new platelet activating factor antagonist (BN 50730) and its two main metabolites in human plasma and urine by LC-MS (1994)
    Springer
    Chromatographia 39 (1994), S. 228-238 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; LC/MS coupling ; Particle Beam interface ; Plasma and urine samples ; BN50730 and its metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and sensitive assay has been developed for the quantitative measurement of a new platelet activating factor antagonist (BN50730), and its two main metabolites (BN50727 and BN50922), at the picomole level in human plasma and urine. The three compounds of interest and the internal standard (BN50765) were measured by combined LC-negative chemical ionization MS. A simple solid-liquid extraction procedure was used to isolate the parent drug and the two metabolites. The MS was tuned to monitor the intense ionm/z 333 generated in the ion source by a dissociative capture process. The assay was on 1 ml plasma or 0.1 ml urine and the quantitation limit was calculated as 1 ng·ml−1. The very low relative standard deviations and mean percentages of error calculated for within-day or between-day repeatability assays demonstrate the ruggedness of the technique for routine determination in biological fluids. Some preliminary results on the pharmacokinetics of the parent drug and its two main metabolites illustrate the applicability of this method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02274505
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  • 5
    Electronic Resource
    Electronic Resource
    Quantitative measurement of clenbuterol at the femtomole level in plasma and urine by combined gas chromatography/negative ion chemical ionization mass spectrometry (1990)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1990), S. 80-88 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive and specific assay was developed for the quantitative measurement of clenbuterol at the femtomole level in human plasma and urine. Clenbuterol and the internal standard (2H9)clenbuterol were measured by gas chromatography/negative ion chemical ionization mass spectrometry with methane as the reagent gas. The two compounds of interest were extracted from the biological samples at pH 13 using ethyl acetate. After two subsequent purification steps, the cleaned-up organic extract was derivatized with pentafluoropropionic anhydride. The mass spectrometer was set to monitor the abundant [M — HCl]- ions of the perfluoroacyl derivatives (m/z 368 and 377), which were generated in the ion source by an electron capture process. This assay required 1 ml of plasma or 0.5 ml of urine and the detection limit of the method was 5 pg ml-1 with a 12.8% relative standard deviation. The accuracy of the clenbuterol assay was also tested day to day with quality control specimens spiked blind to the analyst. The mean difference between the theoretical and actual values was lower than 4.1%.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200190206
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  • 6
    Electronic Resource
    Electronic Resource
    Quantitative measurement of zacopride in human plasma and urine by combined gas chromatography/negative ion chemical ionization mass spectrometry (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 572-580 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive and specific assay was developed for routine analysis of zacopride at the femtomole level in human plasma and urine. Zacopride and the deuterated internal standard [(2H3)zacopride] were measured by gas chromatography/negative ion chemical ionization mass spectrometry with methane as the reagent gas. A multiplestep liquid-liquid extraction procedure was used to isolate the two compounds of interest from complex biological matrices. Zacopride was converted to the fluorinated derivative with pentafluoropropionic anhydride. The mass spectrometer was tuned to monitor the very intense [M — HF]-ion at m/z 435 which was generated into the ion source by a dissociative capture process. This assay was performed with 1 ml of plasma or 0.2 ml of urine, and the quantification limit of the method was calculated as 10 pg ml-1 using a suitable statistical test. The very low relative standard deviation and mean percentage error values calculated during the within-day or between-day repeatability assays have clearly demonstrated the ruggedness of the technique for the routine quantitative measurement of zacopride in plasma and urine. Some preliminary results on the pharmacokinetics of this potent drug are presented to illustrate the applicability of this new powerful gas chromatographic/mass spectrometric method.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200230907
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  • 7
    Electronic Resource
    Electronic Resource
    Quantitative measurement of BN50727 in human plasma and urine by combined liquid chromatography/negative ion chemical ionization mass spectrometry using a particle beam interface (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 581-589 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new sensitive assay has been developed for the quantitative measurement of BN50727 at the picomole level in human plasma and urine. The drug and the internal standard (BN50788) were measured by combined liquid chromatography/negative ion chemical ionization mass spectrometry with methane as the reagent gas. A simple solid-liquid extraction procedure was used to isolate BN50727 from the complex biological matrices. The mass spectrometer was tuned to monitor the intense and stable ion at m/z 333 which was generated in the ion source by a dissociative capture process. This assay was performed with 1 ml of plasma or 0.1 ml of urine and the quantification limit of the method was statistically calculated as 1 ng ml-1. The very low relative standard deviations and mean percentages of error calculated during the different within-day or between-day repeatability assays have clearly demonstrated the ruggedness of the technique for the routine determination of BN50727 in biological fluids. Some preliminary results on the pharmacokinetics of the drug are presented to illustrate the applicability of this powerful liquid chromatographic/mass spectrometric method.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200230908
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  • 8
    Electronic Resource
    Electronic Resource
    A rapid and highly sensitive method for the quantitative determination of dexamethasone in plasma, synovial fluid and tissues by combined gas chromatography/negative ion chemical ionization mass spectrometry (1990)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1990), S. 295-302 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new, simple and highly sensitive assay is developed for the quantitative measurement of very low levels of dexamethasone in human plasma, synovial fluid and tissues following a topical administration of the drug. Dexamethasone and the internal standard, flumethasone, are measured by gas chromatography/negative ion chemical ionization mass spectrometry with methane as the reagent gas. After a three-step extraction procedure, the two compounds of interest are converted to their trimethylsilyl ether derivatives using trimethylsilylimidazole and formamide as the base catalyst. Under soft derivatization conditions only one chromatographic peak corresponding to the trisubstituted derivative is observed. The mass spectrometer is focused to monitor abundant and stable characteristic high-mass ions (m/z 446 and 464) which are generated in the ion source by an electron capture process. This assay requires only 1 ml of plasma or 0.5 ml of synovial fluid and the detection limit of the method is equal to 0.1 ng ml-1 with a relative standard deviation lower than 6%.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200190504
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  • 9
    Electronic Resource
    Electronic Resource
    Quantitative measurement of 4-hydroxy tamoxifen in human plasma and mammary tumours by combined gas chromatography/negative chemical ionization mass spectrometry (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 395-402 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive and specific assay was developed for the quantitative measurement of 4-hydroxy tamoxifen (4-OH Tam) at the femtomole level in human plasma and mammary tumours. The drug and deuterated internal standard (4-OH Tam D4) were measured by gas chromatography/negative chemical ionization mass spectrometry with methane as the reactant gas. The two compounds of interest were isolated from the complex biological matrices using a solid-phase extraction procedure with Extrelut 1 columns. Soft operating conditions were required to convert 4-OH Tam to the fluorinated derivatives with pentafluorobenzyl chloride. The mass spectrometer was tuned to monitor the abundant and stable molecular ions at m/z 581 and 585 which were generated in the ion source by an electron capture process. This assay required only 0.5 ml of plasma or 0.5 g of mammary tissue, and the quantification limits of the method were 20 pg ml-1 for the body fluids or 100 pg g-1 for the tissue samples. The very low relative standard deviation and mean percentage error calculated during the different within-day or day-to-day repeatability assays have clearly demonstrated the ruggedness of the technique for routine analysis of 4-OH Tam.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220706
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    A highly sensitive assay of melatonin at the femtogram level in human plasma by gas chromatography/negative ion chemical ionization mass spectrometry (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 499-509 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive and specific assay was developed for routine analysis of melatonin at the femtogram level in human plasma. Melatonin and the deuterated internal standard [(2H4)melatonin] were measured by gas chromatography/negative ion chemical ionization mass spectrometry with methane as the reagent gas. A simple liquid-liquid extraction procedure was used to isolate the two compounds of interest from the complex biological matrix. Melatonin was converted to the fluorinated derivative with pentafluoropropionic anhydride. The mass spectrometer was tuned to monitor the very intense and stable ions at m/z 320 and 323 which were generated into the ion source by a dissociative capture process. This assay was conducted with 1 ml of plasma and the quantification limit of the method was statistically calculated as 0.5 pg ml- 1. The very low relative standard deviations and mean percentages of error calculated during the within-day or between-day repeatability assays have clearly demonstrated the ruggedness of the technique for the routine quantitative measurement of melatonin in plasma. Some results on the melatonin circadian rhythm are presented to illustrate the applicability of this powerful gas chromatographic/mass spectrometric method.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200230807
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    Paper (German National Licenses)
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