Abstract: AIM: To study the pharmacokinetics of compound olmesartan medoxomil and hydrochlorothiazide tablets after multiple oral dose administration in Chinese healthy volunteers. METHODS: In a randomized, open, single-center study, 12 Chinese healthy volunteers were randomized to administer a single dose of compound olmesartan medoxomil and hydrochlorothiazide tablets (20 mg/12.5 mg) on day 1 and day 3 to day 9. The concentration in human plasma was determined by LC-MS/MS method and its pharmacokinetic parameters were calculated and analysed by DAS 2.0 and SPSS 13.0. RESULTS: The main pharmacokinetic parameters of olmesartan medoxomil after a single dose and multiple-dose were as follows: C_max were (489±122) μg/L and (531±125) μg/L; AUC_0→t were (3468±869 ) μg·L^-1·h and (3557±1209) μg·L^-1·h; t_max were (2.6±0.5) h and (2.3±0.8) h; t_1/2 were (7.3±4.0) h and (8.3±3.6) h, respectively. The main pharmacokinetic parameters of hydrochlorothiazide after a single dose and multiple-dose were as follows: C_max were (122±34) μg /L and (182±38) μg /L; AUC_0→t were (764±211) μg·L^-1·h and (1079±361 ) μg ·L^-1·h; t_max were (2.2±0.7) h and (1.6±0.6) h; t_1/2 were (6.8±2.3) h and (7.1±1.6) h, respectively. CONCLUSION: There is no significant difference in pharmacokinetic parameters of compound Olmesartan medoxomil and hydrochlorothiazide tablets (20 mg/12.5 mg) between single and multiple administration,no accumulation after administration.

Key words: Olmesartan medoxomil, Hydrochlorothiazide, LC-MS/MS, Pharmacokinetics