Bioequivalence study of generic amlodipine in healthy Thai male volunteers

SUBJECTS, MATERIAL AND METHODS: To determine the bioequivalence of 10 mg generic amlodipine in healthy male volunteers, the reference and the test formulations were administered as a single oral dose after overnight fasting in a crossover study separated by 2-week washout interval. After dosing, serial blood samples were collected for a period of 144 h. Plasma amlodipine concentrations were determined by LC-MS/MS and the pharmacokinetic parameters were analyzed by non-compartmental analysis. RESULTS: The mean elimination half-life (t1/2) for the test (40 h) and the reference (44 h) were within the values previously reported. The rate of absorption reflected by tmax had a difference of -0.33 h, with a 90% CI of (-1.52)-0.85 (acceptable range +/- 1.3). Although the tmax of the test (5 h) was faster than the reference (6 h), the mean (90% CI) of the AUC(0-infinity) and Cmax ratios Test/Reference were 0.91 (0.87-0.97) and 1.01 (0.93-1.09), respectively. These values were within the range of 0.80-1.25, thus, the study demonstrated the bioequivalence of the 2 formulations.