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  • 1980-1984  (4)
  • pharmacokinetics  (3)
  • beta-blockade  (1)
  • Chemistry
  • 1
    Digitale Medien
    Digitale Medien
    Bioavailability and pharmacokinetics of theophylline in plain uncoated and sustained-release dosage forms in relation to smoking habit I. Single dose study (1983)
    Springer
    European journal of clinical pharmacology 24 (1983), S. 79-87 
    Details
    ISSN: 1432-1041
    Schlagwort(e): theophylline ; smoking habit ; absolute bioavailability ; pharmacokinetics ; sustained release preparation ; plain tablet preparation ; antipyrine pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The bioavailability and pharmacokinetics of theophylline from a plain uncoated and 2 newly designed, sustained-release tablet formulations, as compared to intravenous aminophylline, were studied in 12 healthy adult male volunteers. The subjects were divided into two groups (n=6) with respect to smoking habit and on 4 separate occasions each received, on a randomized cross-over basis, a single dose of 400 mg equivalent of theophylline from every dosage form. The intravenous aminophylline study showed that habitual smoking had a significant (p〈0.05) effect on plasma theophylline clearance (0.051±0.006 vs 0.035±0.004 l/kg/h). Smoking significantly reduced the raw AUC from the 4 dosage forms (p〈0.05), but did not change the characteristics of absorption of each formulation. There was a non-significant trend towards reduced absolute bioavailability of theophylline from sustained-release formulations in smokers (percentage mean difference — 16% for one formulation and 13% for another). The trend was not observed for the plain uncoated tablet, which was rapidly absorbed (p〈0.01 to 0.05 in Ka, tmax and Cmax compared to sustained-release tablets). Similarity of the in vitro dissolution profiles of the two sustained-release formulations did not imply similarity of the in vivo absorption characteristics. Plasma clearances of theophylline and antipyrine were significantly correlated (p〈0.05,r=0.693,n=10). Thus, smoking enhanced the elimination of theophylline regardless of the dosage form administered. However, the extent to which habitual smoking may affect the hepatic first-pass effect on theophylline from sustained-release formulations requires further study. The results also suggest that theophylline and antipyrine may share a similar or common and presumably polycyclic hydrocarbon-inducible form(s) of microsomal drugmetabolizing enzyme.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00613931
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  • 2
    Digitale Medien
    Digitale Medien
    Concentration-effect and time-effect relationships of carteolol (1983)
    Springer
    European journal of clinical pharmacology 25 (1983), S. 749-757 
    Details
    ISSN: 1432-1041
    Schlagwort(e): carteolol ; beta-blockade ; dose-response relation ; duration of action ; plasma level-effect relation ; pharmacodynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The concentration-beta blocking effect and time-effect relationships of carteolol were examined in eight normal adults given 15 mg i.v. and 20 mg orally on separate occasions. Resting and post-exercise blood pressures and heart rates were assessed before and at various times up to 48 h after each dose. Carteolol, a β-blocker with some partial agonist activity, produced an insignificant, transient increase in heart rate 2 to 6 h after both doses, and a fall (p〈0.05) in diastolic blood pressure 4 and 6 h after the intravenous dose and 6 h after the oral dose in the resting supine position, as compared to the corresponding baseline values. All values of the post-exercise heart rate and the double product after each of the doses were significantly (p〈0.001) below the baseline values for the entire period (48 h) of observation. A significant correlation between the log plasma carteolol concentration (log C) and its beta-blocking effect (E: p〈0.001, r=0.508 i.v.; p〈0.001, r=0.626, p.o.) was found. The r-values for individuals were higher (0.852 to 0.977, intravenous; 0.817 to 0.981, oral) than for the group as a whole. The slope (m) of the relationship, E=m·log C+r, showed a certain variance within and between individuals. When the absolute reduction in exercise-induced heart rate was plotted against time and the rate of decline of effect (Rd) and duration of action were estimated from the time-effect relationship, the mean Rd values were 0.655 and 0.462 beats/min per h, and for the duration of action they were 83.8 and 123.9 h after the intravenous and oral doses, respectively. The effect declined at a slower rate (p〈0.02) and the duration of beta-blockade was longer (p〈0.01) after the oral dose.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00542514
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  • 3
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of ketoprofen following single oral, intramuscular and rectal doses and after repeated oral administration (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 407-414 
    Details
    ISSN: 1432-1041
    Schlagwort(e): ketoprofen ; pharmacokinetics ; relative bioavailability ; single doses ; repeated doses ; prediction of kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of ketoprofen was studied in the same healthy subjects after single oral, intramuscular and rectal doses, and after repeated oral administration. No significant difference in the mean t1/2 (1.13–1.27 h) was observed after the different modes of administration. The mean [AUC] 0 ∞ after rectal administration of a suppository showed the minimum significant difference (p〈0.05) from that after oral administration of the capsule. The apparent volume of distribution (Vd/F) was approximately 10–15% of body weight. The renal contribution (mean, 0.10–0.15 ml/min/kg) to the plasma clearance of free ketoprofen was assumed to be, at most, 8.3–12.9%. The projected cumulative excretion of total (free plus conjugated) ketoprofen via urine exceeded 63–75% of the dose, of which approximately 90% was ketoprofen glucuronide. A mean of 71–96% and 73–93% of the oral capsule was estimated to be systemically available after administration of the intramuscular preparation and rectal suppository, respectively. In four of seven subjects, CPK concentration was elevated after the intramuscular injection. The mean steady-state concentration of ketoprofen in plasma ranged from 0.43 to 5.62 µg/ml after the final dose of a 50 mg q.i.d. regimen. The disposition data and plasma levels observed at steady-state were in agreement with those predicted from the single oral dose study. The accumulation ratio was 1.08±0.08. The results suggest that the rectal suppository can be recommended as an extravascular mode of administration of this drug.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00636794
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  • 4
    Digitale Medien
    Digitale Medien
    Pharmacokinetics and absolute bioavailability of carteolol, a new β-adrenergic receptor blocking agent (1983)
    Springer
    European journal of clinical pharmacology 25 (1983), S. 95-101 
    Details
    ISSN: 1432-1041
    Schlagwort(e): carteolol ; pharmacokinetics ; beta-adrenoreceptor blocking drug ; absolute bioavailability ; plasma levels ; urinary excretion ; renal handling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and absolute bioavailability of a new nonselective β-adrenoreceptor blocking agent, carteolol, were investigated after administration of single intravenous and oral doses to eight normal volunteers. Plasma and urine drug concentrations were measured by an HPLC method. The pharmacokinetic parameters after intravenous dosing were obtained by a two-compartment analysis: elimination or β-phase t1/2 4.7±0.3 h; Vc, 0.74±0.101/kg; Vd, 4.05±0.48 l/kg; Cl, 10.13±0.94 ml/min/kg; ClR, 6.56±0.58 ml/min/kg; and ClNR, 3.57±0.40 ml/min/kg. The absolute bioavailability obtained from plasma data was 83.7±8.0%, which was consistent with that derived from analysis of urine of 82.7±4.2%. The amounts excreted unchanged in urine up to 48 h after the intravenous and oral doses were 65.0±1.5% and 53.8±3.2% of the administered doses, respectively. The t1/2 for removal of the drug derived from plasma and urine findings after intravenous and oral dosing were similar, which indicates that the main route of elimination of carteolol is via the kidneys. As the ClR of carteolol exceeded the Cl of creatinine there may be renal tubular secretion of the drug.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00544023
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