The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
A. Mocan - One of the best experts on this subject based on the ideXlab platform.
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Relative bioavailability of different oral sustained release Oxprenolol tablets.
European journal of drug metabolism and pharmacokinetics, 1998Co-Authors: Sorin E. Leucuta, M. Follidis, R. Capalneanu, A. MocanAbstract:The bioequivalence of oral dosage forms of Oxprenolol was assessed in a triple crossover study on two groups of 12 volunteers each. Single 160 mg doses of Oxprenolol hydrochloride were given after an overnight fast of either Oxprenolol sustained-release tablets in a megaloporous system, a hydrophil matrix and Slow-Trasicor (Ciba-Geigy) in the first group, or floating slow-release tablets administered with food or in absence of food, and rapid release Oxprenolol (Terapia, Cluj-Napoca) tablets, in the second group. Serum Oxprenolol concentrations were measured by a gas chromatographic method. Pharmacokinetic parameters which describe bioavailability and general kinetic behavior of the drug were calculated from individual serum profiles. They were subjected to statistical analysis (paired Student's t test, p
Salah M. Sultan - One of the best experts on this subject based on the ideXlab platform.
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sequential injection method for the determination of Oxprenolol in pharmaceutical products using chemometric methods of optimization
Microchemical Journal, 1997Co-Authors: Fakhr Eldin O Suliman, Salah M. SultanAbstract:Abstract A sequential injection (SI) spectrophotometric method for the determination of Oxprenolol in pharmaceutical products was developed. The method is based on the oxidation of Oxprenolol on-line with Ce(IV) in sulfuric acid medium and the subsequent monitoring of the absorbance of the oxidized form of the drug at 480 nm. The procedure was optimized by the orthogonal array design at two and four levels. The factors included in the optimization were Ce(IV) concentration, sulfuric acid concentration, and the stop time of the composite zone at the reaction coil. The optimized SI system with a linear dynamic range of 50–400 ppm was found to be suitable for the assay of Oxprenolol in pharmaceutical products.
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Kinetic determination of Oxprenolol in pharmaceutical preparations
Analytical Letters, 1991Co-Authors: Salah M. SultanAbstract:Abstract Oxprenolol is kinetically determined using 24.21 mg Cerium(IV) in 0.04 M Sulphuric acid. The absorbance of the brown -red oxidized form of Oxprenolol is measured at 480 nm at a fixed time of 600 seconds. Unknown concentrations of Oxprenolol were calculated by using the calibration graph of the following calibration equation: A=0.08663 + 1.000 × 10−4 C The method was successfully applied to the determination of Oxprenolol in pharmaceutical preparations, and the accuracy was evaluated by statistically comparing the results obtained with the results obtained by the B.P. method.
Sorin E. Leucuta - One of the best experts on this subject based on the ideXlab platform.
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Relative bioavailability of different oral sustained release Oxprenolol tablets.
European journal of drug metabolism and pharmacokinetics, 1998Co-Authors: Sorin E. Leucuta, M. Follidis, R. Capalneanu, A. MocanAbstract:The bioequivalence of oral dosage forms of Oxprenolol was assessed in a triple crossover study on two groups of 12 volunteers each. Single 160 mg doses of Oxprenolol hydrochloride were given after an overnight fast of either Oxprenolol sustained-release tablets in a megaloporous system, a hydrophil matrix and Slow-Trasicor (Ciba-Geigy) in the first group, or floating slow-release tablets administered with food or in absence of food, and rapid release Oxprenolol (Terapia, Cluj-Napoca) tablets, in the second group. Serum Oxprenolol concentrations were measured by a gas chromatographic method. Pharmacokinetic parameters which describe bioavailability and general kinetic behavior of the drug were calculated from individual serum profiles. They were subjected to statistical analysis (paired Student's t test, p
Marc G. Bogaert - One of the best experts on this subject based on the ideXlab platform.
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Direct high-performance liquid chromatography determination of diastereomeric Oxprenolol glucuronides
Journal of chromatography. B Biomedical applications, 1996Co-Authors: Martine E. Laethem, Frans Belpaire, Marc G. BogaertAbstract:The β-blocking agent Oxprenolol is used therapeutically as the racemate. In humans and animals it is metabolized i.a. to ether glucuronide diastereomers. A stereoselective HPLC assay was developed to determine directly, without hydrolysis to their parent enantiomers, the Oxprenolol glucuronides in biological samples. The glucuronide standards for this direct assay are prepared by incubation of rabbit liver microsomes with RS-Oxprenolol. The glucuronides obtained are purified and concentrated with solid-phase extraction, and their concentration is measured by an indirect method, i.e. HPLC assay of the Oxprenolol enantiomers after enzymatic hydrolysis with β-glucuronidase. The direct assay involves separation by HPLC using a C18-reversed-phase column, with UV detection at 274 nm; nalorphine is used as internal standard. On injection onto the column, without previous hydrolysis, the limit of detection is 20 ng for both glucuronides. The assay is sensitive, accurate and reproducible. The method is suitable for the assay of glucuronides in liver microsomal incubates and plasma.
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Stereoselective pharmacokinetics of Oxprenolol and its glucuronides in humans
Clinical pharmacology and therapeutics, 1995Co-Authors: Martine E. Laethem, Romain Lefebvre, Frans Belpaire, Hans Vanhoe, Marc G. BogaertAbstract:Objective To study the pharmacokinetics of R(+)- and S(−)-Oxprenolol and their corresponding glucuronide conjugates in healthy subjects. Methods An oral dose of 80 mg racemic Oxprenolol was given to eight male volunteers. Venous blood samples and urine were collected as a function of time. Oxprenolol enantiomers in plasma and urine were determined by an enantiospecific HPLC method. Oxprenolol glucuronides in plasma and urine were measured as Oxprenolol equivalents after enzymatic hydrolysis. Results For R-Oxprenolol the area under the plasma concentration—time curve was slightly higher (RS ratio, 1.19) and the oral clearance slightly lower (RS ratio, 0.84) than those parameters for S-Oxprenolol. The free fraction of R-Oxprenolol in plasma was 4% higher than that of S-Oxprenolol. The intrinsic clearance of S-Oxprenolol was 1.5 times larger than that of R-Oxprenolol, and a maximum of 3% of the dose was excreted as unchanged enantiomers in the urine. The plasma concentrations of S-Oxprenolol glucuronide were more than three times higher than those of R-Oxprenolol glucuronide. Twenty-five percent of the dose of the R-enantiomer was excreted in the urine as R-Oxprenolol glucuronide; 29% of the S-enantiomer dose was excreted as S-Oxprenolol glucuronide. The renal clearance of R-Oxprenolol glucuronide was, on average, 172 ml/min, suggesting active tubular secretion. In contrast, the renal clearance of S-Oxprenolol glucuronide was only 49 ml/min, which can be explained by the plasma binding of the compound. Conclusions Our results show small differences in disposition between R- and S-Oxprenolol but a marked difference in disposition between the glucuronides. The difference in plasma concentrations between the Oxprenolol glucuronides is mainly attributable to the stereoselectivity of the renal excretion. Clinical Pharmacology & Therapeutics (1995) 57, 419–424; doi:
C J Van Boxtel - One of the best experts on this subject based on the ideXlab platform.
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the effect of Oxprenolol dosage time on its pharmacokinetics and haemodynamic effects during exercise in man
European Journal of Clinical Pharmacology, 1993Co-Authors: Richard P Koopmans, B Oosterhuis, J M Karemaker, J Wemer, C J Van BoxtelAbstract:We have studied the effect of dosage time of Oxprenolol (Trasicor®) on its pharmacokinetics and pharmacodynamics in six healthy volunteers. The drug effects measured were heart rate and systolic blood pressure during exercise. Oxprenolol was taken orally at 08.00 h, 14.00 h, 20.00 h, and 02.00 h in randomized order, with 1 week between successive doses.
