An open randomized crossover test on 18 healthy volunteers was used to study the pharmacokinetics of anvifen (acting substance, aminophenylbutyric acid) manufactured in capsules at the Joint-Stock Company "Antiviral" (Russia). The test was performed after single peroral administration in comparison with phenibut tablets of the same manufacturer. The concentration of unchanged aminophenylbutiric acid in the blood plasma was measured by HPLC with UV detection. It is established that anvifen and phenibut are bioequivalent in terms of pharmacokinetics.

Открытым рандомизированным перекрестным методом у 18 здоровых добровольцев изучена фармакокинетика анвифена (действующее вещество - аминофенилмасляная кислота) в капсулах производства ЗАО НПО Антивирал (Россия) после однократного приема в сравнении с таблетками Фенибут того же производителя. Концентрацию неизмененной аминофенилмасляной кислоты в плазме крови измеряли методом ВЭЖХ с УФ-детектированием. Установлено, что Анвифен и Фенибут биоэквивалентны.

Aim. To compare the pharmacokinetics and pharmacodynamics of verapamil retard, regularly taken by patients with Stage I-II arterial hypertension (AH). Material and methods. The effects of the administration time (morning vs. evening) on verapamil retard pharmacokinetics were investigated. This open, randomised, cross-over study included 14 patients with Stage I-II AH, who were regularly administered verapamil retard for 3 weeks. Before the active therapy started, all antihypertensive medications were withdrawn, with an exception of short-acting agents (“wash-out” period). Two weeks later, the patients were administered verapamil retard, according to the randomisation scheme, and were recommended to take one tablet in the morning or evening, at the same time every day. The first administration was at the clinic, under medical supervision. Three weeks later, the participants were hospitalised for pharmacokinetics assessment. Seven days after the end of the first treatment course, a second course started, with an inverted time of verapamil retard administration. Blood concentration of non-modified verapamil was measured by high-performance liquid chromatography with fluorescent detection. Results. Significant differences in pharmacokinetics were observed for morning vs. evening verapamil administration. The respective maximal verapamil concentrations were 239,7±152,3 vs. 148,6±107,4 ng/ml (p<0,01), and respective half-life times were 12,50±3,48 vs. 22,57±15,24 hours (p<0,05). For other parameters, the difference was non-significant. Conclusion. In Stage I-II AH patients, the morning administration of Isoptin SR resulted in accelerated increase of its plasma concentration. At the same time, the evening administration was associated with increased half-life time and higher “concentration-effect” correlation, which makes the latter variant more rational.

Aim. To compare the pharmacokinetics and pharmacodynamics of verapamil retard, regularly taken by patients with Stage I-II arterial hypertension (AH)Material and methods. The effects of the administration time (morning vs evening) on verapamil retard pharmacokinetics were investigated This open, randomised, cross-over study included 14 patients with Stage I-II AH, who were regularly administered verapamil retard for 3 weeks Before the active therapy started, all antihypertensive medications were withdrawn. with an exception of short-acting agents ("wash-out" period) Two weeks later, the patients were administered verapamil retard, according to the randomisation scheme, and were recommended to take one tablet in the morning or evening, at the same time every day The first administration was at the clinic, under medical supervision Three weeks later, the participants were hospitalised for pharmacokinetics assessment Seven days after the end of the first treatment course, a second course started, with an inverted time of verapamil retard administration. Blood concentration of non-modified verapamil was measured by high-performance liquid chromatography with fluorescent detectionResults. Significant differences in pharmacokinetics were observed for morning vs. evening verapamil administration The respective maximal verapamil concentrations were 239,7+/-152,3 vs 148,6+/-107,4 ng/ml (p<0.01). and respective half-life times were 12.50+/-3,48 vs 22,57+/-15,24 hours (p<0,05) For other parameters. the difference was non-significantConclusion. In Stage I-II AH patients. the morning administration of Isoptin SR resulted in accelerated increase of its plasma concentration. At the same time, the evening administration was associated with increased half-life time and higher "concentration-effect" correlation, which makes the latter variant more rational