Abstract: AIM:To study the pharmacokinetics of amlodipine after coadministration of benazepril (10mg) plus amlodipine (5mg), or amlodipine (5mg) alone in healthy volunteers, and to evaluate the effects of pharmacokinetic interaction between amlodipine and benazepril.METHODS:Twelve male healthy volunteers were enrolled in a randomized two-way crossover study. An LC-MS-MS method was established for the determination of amlodipine in human plasma, and the data were analysed by WinNonLin software.RESULTS:The mean pharmacokinetic parameters of amlodipine after coadministration with benazepril plus amlodipine, or amlodipine alone were as follows:C_max were (2.6 ±0.6) and (2.8 ±0.7) μg/L,AUC_{0 -144} were (99 ±39) and (109 ±26) μg^。L ^-1。h, t max were (5.8 ±1.3) and (5.3 ±1.0) h, t_1/2 were (37 ±6) and (44 ±12) h, respectively.There were no significant differences in these parameters between coadministration of benazepril plus amlodipine and amlodipine administered alone (P >0.05 ).CONCLUSION:Coadministration with benazepril did not significantly affect the pharmacokinetics of amlodipine.

Key words: amlodipine, benazepril, HPLC-MS/MS, pharmacokinetics, interaction