Relative bioavailability study of two nifedipine tablet formulations in healthy male volunteers

Objective: To assess the bioequivalence of two oral formulations containing 10 mg of nifedipine. The test preparation were Macorel tablets, the refere nce preparation were Adalat tablets. Subjects, material and methods: The st udy was designed as a single-dose, three-period crossover randomized design to 18 non-smoker, healthy male volunteers under fasting conditions. Sevent een volunteers completed the study. Plasma samples were analyzed for nifedi pine by HPLC after solid-phase extraction. The pharmacokinetic parameters u sed to assess the bioequivalence of the two formulations were AUC(0-infinit y), and AUC(0-t) for the extent of absorption and C-max and T-max for the r ate of absorption. Statistical comparisons of AUC(0-infinity),, AUC(0-t) an d C-max data were evaluated after logarithmic transformation by two-way ana lysis of variance (ANOVA),and differences of T-max were tested non-parametr icaly. Results: Point estimates (90% confidence intervals) of the test/refe rence ratios were 97.4% (87.6% - 108.3%) for AUC(0-infinity) 97.0% (85.6% - 110.1%) for AUC(0-t), and 107.7% (89.1% - 130.7%) for C-max. No statistica lly significant difference was found for T-max and elimination half-life va lues. Conclusion: Therefore, in accordance with the European Union bioequiv alence requirements, the test and reference nifedipine preparations are bio equivalent for both the extent and the rate of absorption.