Bioequivalence study of amlodipine maleate tablet and amlodipine besylate tablet (Norvasc) in healthy Chinese subjects

摘要

The aim of this study was to investigate the pharmacokinetics of amlodipine after a single oral dose of amlodipine maleate tablet in healthy Chinese subjects and to evaluate the bioequivalence between amlodipine maleate tablet and Norvasc. Twenty healthy Chinese subjects received a single oral dose of 10 mg amlodipine either as amlodipine maleate tablet or as Norvasc in a randomized, open label, two-way crossover study. Amlodipine in human plasma was determined by a sensitive liquid chromatographic-tandem mass spectrometry (LC/MS/MS) method. Mean maximum concentration (C_(max)) of amlodipine was 8.68mug L~(-1) at 6.3 hours for amlodipine maleate tablet and 8.63mug L~(-1) at 6.8 hours for Norvasc. Mean area under the plasma concentration-time curve from zero to last measured point (AUC_(0-t)) for amlodipine maleate tablet was 374.5mug·h·L~(-1) compared with 357.0mug·hL~(-1) for Norvasc. The apparent elimination half-life (T_(1/2)) of amlodipine for amlodipine maleate tablet was 43.2 hours and was 39.4 hours for Norvasc, respectively. The analysis of variance on C_(max) and AUC indicated that there was no significant difference between the two products. All 90% confidence intervals (CIs) of the test/reference geometric mean ratio were within the bioequivalence limits. The conclusion of the study is that the pharmacokinetic profiles of amlodipine in healthy Chinese subjects are the same after a single doses of the formulations of maleate salt and besylate salt