Comparative bioavailability of two amlodipine formulations in healthy volunteers

The present study was conducted to find out whether the bioavailability of a 10 mg amlodipine (CAS 88150-42-9) tablet (Intervask((R)), "test") was equivalent to that that of a reference formulation ("reference"). The pharmacokinetic parameters assessed in this study were area under the serum concentration-time curve from time zero to 144 h (AUC(t)), area under the serum concentration-time curve from time zero to infinity (AUC(inf)), the peak serum concentration of the drug (C-max), time needed to achieve the peak serum concentration (t(max)), and elimination half life (t(1/2)). This was a cross-over, randomized, single-blind study which included 12 healthy male and female volunteers under fasting condition. In each of the two study periods (separated by a washout of 3 weeks) a single dose of test or reference drug was administered. Blood samples were taken up to 144 h post dose, the plasma was separated and the concentrations of amlodipine were determined by a LC/MS method. The mean AUC(t), AUC(inf), C-max, and t(1/2) were 353.15 ng center dot h/mL, 417.86 ng center dot h/mL, 8.08 ng/mL, and 48.04 h, respectively, for the test drug and 359.99 ng center dot h center dot mL(-1), 408.23 ng center dot h/mL, 8.22 ng/mL, and 43.81 h, respectively, for the reference drug. The median T-max of the test drug and reference drug were 8.0 h and 8.5 It, respectively. The point estimators of the ratios test/reference drug for AUC(t), AUC(inf), and C-max were 96,26%, 99.48% and 97.03%, respectively. Furthermore, the 90% confidence intervals of the mean ratio of In-transformed were 83.73-110.68% for AUC(t) 81.79-120.99% for AUCinf, and 81.94-114.81% for C-max center dot It can be concluded that the two amlodipine tablets (test drug and reference drug) are bioequivalent in terms of the rate and extent of absorption.