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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 323-324 
    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
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 375-378 
    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
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 407-409 
    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.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 423-426 
    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
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 433-437 
    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.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 25-28 
    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.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 375-379 
    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.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 279-282 
    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%).
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  • 9
    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.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 589-594 
    ISSN: 1432-1041
    Keywords: ketoprofen ; probenecid ; cholecystectomy ; enantiomers ; glucuroconjugates ; stereoselectivity ; T-tube patients ; biliary excretion ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Ketoprofen (KT), a 2-arylpropionic acid nonsteroidal antiinflammatory drug, is administered as a racemate. Previous reports suggest stereoselective biliary excretion of KT enantiomers. This hypothesis was tested by administering 50 mg racemic KT to five patients who required bile drainage following cholecystectomy surgery. Subsequently, to study the influence of probenecid (PB), an inhibitor of KT renal elimination, on the biliary excretion, 1000 mg PB was administered 1.5 h before KT to the same patients. The unchanged and conjugated (as glucuronides) KT enantiomers were measured in plasma, urine and bile. In general, KT enantiomers had different plasma concentration-time curves. As compared to normal subjects, these patients had comparable AUCs and shorter t1/2s. Biliary concentrations of conjugated S-KT were greater than R-KT. Nevertheless, the total cumulative biliary excretion of conjugated KT did not exceed 2% of the dose ruling out this pathway as a significant route of KT elimination. There was a positive and significant correlation between the cumulative urinary excretion of conjugated KT enantiomers and creatinine clearance. Although PB did not influence the pattern of stereoselectivity of KT, it increased AUC and prolonged t1/2 of the enantiomers. While reducing cumulative urinary excretion, PB increased total biliary elimination of conjugated KT enantiomers. This, however, did not totally compensate for the reduced urinary excretion. It is suggested that the impaired conjugation of KT caused by PB administration may result in the augmentation of other, otherwise minor, metabolic pathways.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 613-616 
    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.
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  • 12
    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.
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  • 13
    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.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 181-184 
    ISSN: 1432-1041
    Keywords: baclofen ; renal function ; healthy subjects ; pharmacokinetics ; probenecid ; tubular secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Baclofen, a centrally acting muscle relaxant, is used in the treatment of spasticity. Its pharmacokinetics has been derived from plasma and urine data in four healthy subjects, whose renal function was simultaneously measured. After oral administration of a single 40 mg dose, baclofen was mainly excreted unchanged by the kidney, 69 (14) %. The half-life, calculated from extended least squares modelling (ELSMOS) both of plasma and urine data was 6.80 (0.68) h, which is longer than reported in most studies based solely on plasma data. The renal excretion rate constant had the high mean value of 0.35 (0.24) h−1, and the apparent renal clearance of baclofen equalled the creatinine clearance. Passive tubular reabsorption is relatively unimportant, since no dependence was observed on variables urine flow or pH. Although active tubular secretion may contribute to its renal clearance, as shown by the effect of coadministration of probenecid, glomerular filtration appears to be the dominant transport mechanism.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 185-189 
    ISSN: 1432-1041
    Keywords: nifedipine ; renal failure ; pharmacokinetics ; protein binding ; blood pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The total and free steady-state plasma levels of nifedipine in patients with renal failure have been compared with those in subjects with normal renal function. Studies were done after administration of nifedipine 10 mg t.d.s. p.o. for 5 days, after i.v. infusion of 4·4 mg, and after a single 10 mg oral dose. The systemic clearance of nifedipine after a single i.v.-dose was higher in subjects with renal insufficiency (854 ml/min) than in those with normal renal function (468 ml/min). After the single oral dose the AUC (6100 ng·min·ml−1) and maximum plasma concentration (75.0 ng·ml−1) were lower than in subjects with normal renal function (19300 ng·ml−1; 122 ng·ml−1). The plasma protein binding of nifedipine averaged 95.5% in normal subjects and 94.8% in patients with renal failure. Although free and total steady-state plasma levels of nifedipine tended to be somewhat lower than normal in renal failure, the changes in pharmacokinetics and decreased protein binding of nifedipine did not result in a significantly different steady-state plasma level of the drug. The blood pressure response to a given plasma nifedipine level appeared to be enhanced in renal failure.
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  • 16
    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.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 313-316 
    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.
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  • 18
    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.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 577-580 
    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.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 283-290 
    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.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 383-388 
    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.
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  • 22
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 395-400 
    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).
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  • 23
    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.
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  • 24
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    European journal of clinical pharmacology 36 (1989), S. 67-70 
    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.
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  • 25
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    European journal of clinical pharmacology 36 (1989), S. 79-82 
    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.
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  • 26
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    European journal of clinical pharmacology 37 (1989), S. 161-166 
    ISSN: 1432-1041
    Keywords: midazolam ; benzodiazepine ; pharmacokinetics ; biotransformation ; surgery ; prolonged recovery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of midazolam has been studied in patients recovering from cardiac surgery, who required sedation for postoperative mechanical ventilation. Twelve males (mean age 64.5 years) with severe heart disease received an infusion of midazolam 15 mg·h−1 for 4 h, starting 1 to 3 h post surgery. Multiple blood samples were collected from each patient during the infusion and up to 48–93 h after it. The pharmacokinetic parameters of midazolam were determined using both moment analysis and the program NONMEM. The average terminal half-life was 10.6 h. The prolonged elimination was mainly due to a decrease in its metabolic clearance (0.25 l·min−1). The maintenance infusion dose of midazolam in such patients should be reduced. The time to recovery after stopping an infusion depends upon the amount of drug in the body at that time and a simulation of the plasma concentrations after various infusion regimens suggests that recovery will be delayed after prolonged (〉48 h) administration of midazolam to these patients. However, after shorter infusions (〈12 h), redistribution of the drug away from the site of action was still occurring and recovery would be expected to be relatively rapid.
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  • 27
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    European journal of clinical pharmacology 37 (1989), S. 173-180 
    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.
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  • 28
    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.
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  • 29
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    European journal of clinical pharmacology 37 (1989), S. 613-615 
    ISSN: 1432-1041
    Keywords: verapamil ; pharmacokinetics ; circadian rhythm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Circadian variation in the metabolism of verapamil was investigated in 10 patients with stable angina pectoris during treatment with sustained-release verapamil 360 mg at 08.00 h or 22.0 h. No major difference in exercise parameters was found. During the evening dosage schedule a significantly greater bioavailability (AUC) and a prolonged time to peak concentration was found. During the night (24.00 h–06.00 h) the half-life of verapamil was significantly longer than during the day (16.00 h–22.00 h). These differences in pharmacokinetics may be due to reduced hepatic blood flow at night or to circadian variation in hepatic microsomal metabolism.
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  • 30
    ISSN: 1432-1041
    Keywords: acetyl-L-carnitine ; renal clearance ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of acetyl-L-carnitine hydrochloride were investigated in 6 healthy volunteers of both sexes after i.v. injection of 500 mg of the drug, expressed as inner salt. Plasma concentrations and urinary excretion of acetyl-L-carnitine (A), L-carnitine (B) and total acid soluble L-carnitine fraction were evaluated over a period lasting from 24 h before to 48 h after the administration. Plasma concentrations of A increased quickly after administration and then declined reaching base values within 12 h. Conversely, plasma concentrations of B rose more slowly, reaching a peak in 30–60 min, and then declined to base values within 24 h. Most of the injected dose of acetyl-L-carnitine was recovered in the urine during the first 24 h after administration as B and A. Mean renal clearance of both A and B during the first 12 h after injection was higher than the base values, suggesting the presence of a saturable tubular reabsorption process which may counterbalance major changes occurring in plasma concentrations of L-carnitine pattern.
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  • 31
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    European journal of clinical pharmacology 37 (1989), S. 75-77 
    ISSN: 1432-1041
    Keywords: dexamethasone ; congenital adrenal hyperplasia ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of dexamethasone, given at low dose, were studied in 13 patients with congenital adrenal hyperplasia (CAH) to ascertain whether kinetics differed in this inherited disorder of cortisol metabolism from those seen in healthy individuals. Changes in plasma dexamethasone concentration after intravenous bolus, measured using a simple novel radioimmunoassay, were well described by a two-compartment open model with first-order kinetics. Values for λ2: 0.206 h−1, t1/2: 3.53 h, Vc: 24.41 and f: 0.64 were similar to those previously reported for normal subjects. There were considerable interindividual differences in parameter values and Cmaxp.o. (range 22–67 nmol/l). As suppression of the hypothalamo-pituitary-adrenal axis correlates with plasma dexamethasone levels, this variability may partly explain the differing dose and dose schedule requirements necessary to achieve adequate therapeutic control in the clinical management of CAH.
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  • 32
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    European journal of clinical pharmacology 37 (1989), S. 85-90 
    ISSN: 1432-1041
    Keywords: theophylline ; sustained-release formulation ; bioavailability ; fatty food ; dumping effect ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A cross-over study of kinetics has been undertaken in 12 healthy adults volunteers using two sustained-release theophylline products that allow once a day dosing (Theo-Dur tablets and Dilatrane A.P. bead filled capsules) to compare the i.v. pharmacokinetic profiles when taken with an hyperlipidic meal and a balanced standard meal. Each subject took part in four phases in randomised order, corresponding to all possible combinations of the products and the types of meal. Each phase involved a single dose of 9 to 11 mg·kg−1 theophylline administered at 20.00 h, at the beginning of the meal, with 100 ml water. The two formulations were found to be bioequivalent with both types of meal. Taken with a balanced meal, the mean parameters were similar; for Theo-Dur and Dilatrane A.P. they were respectively: Cmax: 11.32 mg·l−1 which plateaued from 8 to 10 h after dosing and 10.9 mg·l−1, which plateaued after 6 to 10 h; AUC 230 mg·h·l−1 and 220 mg·h·l−1; and MRT 18.2 h and 17.7 h. After the hyperlipidic meal the values for Theo-Dur and Dilatrane A.P. respectively, were: Cmax 10.9 mg·l−1 at 12 h and 11.3 mg·l−1 at 10 h; AUC 237 mg·h·l−1 and 227 mg·h·l−1; and MRT 19.2 h and 18.9 h. In spite of a decrease in the absorption rate, which led to a shift to the right of about 2 h of the plasma concentration-time curve, the bioavailability of both formulations were not significantly modified by a hyperlipidic meal as compared to a balanced meal. The shift of the curve with fatty food was not clinically important, as there was no dumping effect. The main difference between the two formulations was seen during the absorption phase, which was linear and less variable with Dilatrane A.P. and sigmoidal with Theo-Dur. This was observed with both types of meal.
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  • 33
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    European journal of clinical pharmacology 37 (1989), S. 97-100 
    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.
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  • 34
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    European journal of clinical pharmacology 37 (1989), S. 167-171 
    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.
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  • 35
    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.
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  • 36
    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.
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  • 37
    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.
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  • 38
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    European journal of clinical pharmacology 36 (1989), S. 291-297 
    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.
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  • 39
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    European journal of clinical pharmacology 36 (1989), S. 467-471 
    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.
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  • 40
    ISSN: 1432-1041
    Keywords: salbutamol ; asthma ; controlled-release formulation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Fifteen patients with asthma were given salbutamol controlled-release (SCR) 4 mg or 8 mg twice daily for seven days, in a randomised double-blind cross-over design. Plasma salbutamol levels were measured after the first and fifteenth doses for a 12 h period following drug ingestion. At steady-state the geometric mean values for Cmax were 8.2 ng/ml for 4 mg, and 16.1 ng/ml for 8 mg. Median tmax values were 300 and 240 min respectively. The geometric mean AUC (0–12) were 4507 ng·min·ml−1 and 8980 ng·min/ml. Peak to trough fluctuation ratios were 0.577 and 0.572. There were no significant differences between 4 mg or 8 mg formulations, for any of the parameters measured, after appropriate corrections for dose. The concentration-time profiles at steady-state showed little fluctuation in plasma salbutamol levels over the twelve hour dosing interval. These results show that 4 mg and 8 mg formulations of SCR provide smooth plasma profiles at steady-state with a twice daily dosing regime.
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  • 41
    ISSN: 1432-1041
    Keywords: alfuzosin ; prazosin ; alpha1-adrenoceptor antagonist ; noradrenaline ; pharmacokinetics ; pharmacodynamics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In an open dose ranging study with random inclusion of placebo, alfuzosin (α1-adrenoceptor antagonist) 1, 2.5 and 5 mg was administered to 6 healthy volunteers, 3 of the volunteers received 10 mg alfuzosin. Supine systolic blood (SBP) pressure was not reduced by alfuzosin although significant increases occurred in supine heart rate (HR) after 2.5 and 5 mg. In the standing position, SBP was reduced at 2 and 4 h with 5 mg alfuzosin; significant increases in HR occurred following 1, 2.5 and 5 mg at 2, 4, 6 and 8 h after administration. Exercise SBP was not reduced; diastolic blood pressure was significantly reduced at 4 and 6 h with 5 mg alfuzosin. More marked effects were seen in the 3 subjects who received 10 mg alfuzosin. After 1 and 5 mg, tmax ranged from 1–2 h; Cmax (4.1 to 20.8 ng · ml−1; AUC (0–24) 20 to 132 ng · ml−1 · h (1 and 5 mg respectively) increased progressively with dose indicating dose dependent kinetics; no significant changes occurred in the visual analogue scale for sedation. A comparison of alfuzosin 5 mg, prazosin 1 mg and placebo each administered for 4 days, indicated that alfuzosin did not significantly reduce standing SBP on either Day 1 or Day 4; prazosin reduced SBP at 2 and 4 h on Day 1 and 6 h on Day 4 compared to placebo. Standing HR was increased by alfuzosin at 2 h on Day 1 and Day 4; increases occurred with prazosin at 2, 4, 6 and 8 h on Day 1 and 6 h on Day 4. Supine plasma noradrenaline increased with alfuzosin and prazosin at 2 and 4 h on Days 1 and 4; the increases were not significantly different. The plasma elimination half-life (t1/2) for alfuzosin was 3.4 h and 3.1 h after acute and chronic administration; (t1/2) for prazosin was 2.6 and 2.9 h. In conclusion alfuzosin causes small reductions in systolic blood pressure, accompanied by a dose dependent increase in heart rate in the supine and standing position and following exercise.
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  • 42
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    European journal of clinical pharmacology 37 (1989), S. 69-74 
    ISSN: 1432-1041
    Keywords: oxcarbazepine ; pharmacokinetics ; drug metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of oxcarbazepine (a new anticonvulsant which is a congener of carbamazepine) and of its 10-hydroxy metabolite were studied at the outset of therapy in 8 adult epileptics comedicated with other anticonvulsants. The pharmacokinetic study was repeated under steady-state conditions after 3 months of drug intake in 6 of these subjects. The plasma elimination half-life of oxcarbazepine appeared to lie in the range 1.0–2.5 h, and that of its 10-hydroxy metabolite averaged 8.4 h. The apparent oral clearance of the parent drug (averaging 2.51·kg−1·h−1) was high enough to suggest substantial presystemic elimination. The oral clearance fell after 3 months of drug intake, but the half-lives of the drug and metabolite showed no statistically significant change over this time. Steady-state plasma levels of both drug and metabolite were linearly related to drug dose, metabolite levels averaging 9 times those of the parent substance.
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  • 43
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    European journal of clinical pharmacology 36 (1989), S. 103-109 
    ISSN: 1432-1041
    Keywords: asthma ; chronopharmacology ; theophylline ; circadian rhythms ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
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  • 44
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    European journal of clinical pharmacology 37 (1989), S. 279-283 
    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.
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  • 45
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    European journal of clinical pharmacology 37 (1989), S. 321-322 
    ISSN: 1432-1041
    Keywords: cyclosporin ; synovial fluid ; rheumatoid arthritis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
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  • 46
    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.
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  • 47
    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.
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  • 48
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 205-208 
    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
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  • 49
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 36 (1989), S. 209-211 
    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.
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  • 50
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 487-491 
    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.
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  • 51
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 501-506 
    ISSN: 1432-1041
    Keywords: N-acetylcysteine ; paracetamol ; acetaminophen overdose ; pharmacokinetics ; liver damage ; adverse reactions ; dose modifications
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Seventeen patients received standard treatment with intravenous N-acetylcysteine for 18 episodes of severe poisoning with paracetamol (acetaminophen). The dose of N-acetylcysteine was 150 mg/kg given in 15 min followed by 50 mg/kg in 4 h and 100 mg/kg over the next 16 h. Liver damage was absent or mild on 13 occasions (ALT〈500 µ/l) and severe on 5 (ALT〉1000 µ/l). Total plasma N-acetylcysteine was estimated by HPLC. The mean maximum plasma concentration after the initial loading dose was 554 mg/l. Concentrations then fell rapidly and after 12 h a mean steady-state level of about 35 mg/l was maintained. When the infusion was discontinued N-acetylcysteine disappeared with a half-life of 5.7 h. The mean steady-state volume of distribution, AUC, mean residence time and total clearance were 536 ml/kg, 1748 mg·h·l−1, 2.91 h and 3.18 ml·min−1·kg−1. These values are generally consistent with those previously reported with much smaller doses and the disposition of N-acetylcysteine does not appear to be dose-dependent. The elimination of N-acetylcysteine was not impaired in the patients with severe liver damage, and the pharmacokinetic variables and plasma concentrations were similar in patients with and without hepatotoxicity. The dosage schedule for intravenous N-acetylcysteine should probably be modified since adverse reactions invariably occur early when plasma concentrations are at their highest, and liver damage was prevented just as effectively at the lowest as at the highest Cmax. High initial concentrations of N-acetylcysteine can be avoided with simple alternative regimens based on the kinetic data of this study.
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  • 52
    ISSN: 1432-1041
    Keywords: oxitropium bromide ; pharmacokinetics ; radioreceptor assay ; side-effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Oxitropium bromide (OXBR) is a new anticholinergic drug, which is expected to be useful in the treatment of nocturnal asthma. The only pharmacokinetic data were obtained with the14C-labelled compound. A sensitive radioreceptor assay for the determination of unlabelled OXBR in plasma was developed, based on competition between OXBR and3H-N-methylscopolamine for binding to muscarinic receptors. OXBR was isolated from plasma by ion-pair extraction and re-extraction. Active metabolites present in significant amounts might interfere in the assay, but this was not the case for OXBR metabolites. Detection limits were 300 pg·ml−1 and 3 ng·ml−1 for plasma and urine, respectively. For the latter no extraction step was required. The single dose pharmacokinetics of OXBR was studied following inhalation (3 mg), oral (2 mg) and i.v. (1 mg) administration to 12 men, following an open, cross-over design. After i.v. administration the kinetic parameters were: Vc 38.4 l; t1/2α 5.3 min; t1/2β 142 min; AUC 8.9 h·ng·ml−1; renal excretion 50.2%, k10 3.5 l·h−1 and total clearance 1874 ml/min. The apparent bioavailabilities were 0.48% and 12.4% by the oral and inhalation routes, respectively, based on the cumulative renal excretion. There were moderate adverse reactions due to the anticholinergic properties of the drug.
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  • 53
    Electronic Resource
    Electronic Resource
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    European journal of clinical pharmacology 36 (1989), S. 507-512 
    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.
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  • 54
    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.
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  • 55
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 267-272 
    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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  • 56
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 261-265 
    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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  • 57
    Electronic Resource
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    Springer
    European journal of clinical pharmacology 37 (1989), S. 359-363 
    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.
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  • 58
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 37 (1989), S. 387-389 
    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.
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  • 59