Pharmacokinetics, Bioequivalence, and Safety Studies of Amlodipine Besylate in Healthy Subjects

This study aimed to evaluate the bioequivalence of 2 amlodipine besylate tablet formulations, a generic formulation and an original formulation, and to investigate their pharmacokinetic and safety profiles. This study was designed as a randomized, open-label, single-dose, crossover, dual-period study and was divided into fasting and postprandial human bioequivalence trials. In the first trial after overnight fasting, 28 subjects were given 5-mg amlodipine besylate tablets via oral administration, and blood specimens were obtained up to 144 hours after dosing; another 28 subjects had a high-fat meal 1 hour before drug administration and proceeded the same as the fasting trial. Bioequivalence was evaluated using 90%CIs for the ratio test/reference of log area under the concentration-time curve (AUC) from time 0 to the last quantifiable concentration, log AUC from time 0 to infinity, and log peak concentration. The plasma concentrations were measured by high-performance liquid chromatography-tandem mass spectrometry. The safety was assessed throughout the study. The results show that no significant differences were observed between the pharmacokinetic profiles of the test and reference amlodipine besylate tablets in the fasting and postprandial trials. The 90%CIs of the peak concentration, AUC from time 0 to the last quantifiable concentration and AUC from time 0 to infinity of amlodipine in the 2 trials were within the commonly accepted bioequivalence criteria of 80% to 125%. Compared with the pharmacokinetic parameters of the fasting and postprandial trials, food had no significant effect on exposure of amlodipine besylate. There was no significant difference in safety statistical results between the 2 groups. The results suggest that generic and original amlodipine besylate tablets are bioequivalent with similar safety profiles.