Study on the relative bioavailability of metformin hydrochloride sustained-release tablets

Objective:To study the relative bioavailability and pharmacokinetics of metformin hydrochloride sustained-release tablets. Methods: Single and multi-dose of metformin hydrochloride tablets and sustained-release tablets were given to 18 male volunteers in a random cross-over design.Plasma samples were obtained and were determined by HPLC with UV detector,and then the bioavailability and pharmacokinetics of the two drugs were studied. Results: After the application of a 500 mg single dose to volunteers,the pharmacokinetics parameters of metformin hydrochloride tablets and sustained-release tablets were as follows: C_(max) were(1.189±0.528) μg/mL and (0.779±0.368) μg/mL,T_(max) were(1.56±(0.56) h) and(2.67±1.26)h;AUC_(0→t) were(7.006±3.016) μg·h·mL~(-1) and(7.176±3.134) μg·h·mL~(-1),respectively.The relative bioavailability of the sustained-release tablets were (103.38±14.68)%.After the application of multi-dose to volunteers,the pharmacokinetics parameters were: C_(max) were(0.783±0.192) and (1.037±0.281)μg/mL;T_(max) were(1.56±0.29) h and(3.12±0.58) h,AUC_(0→t) were((4.158±)1.033) μg·h·mL~(-1) and(6.585±1.647) μg·h·mL~(-1),DF were 2.79±0.56 and 2.71±0.68. Conclusions: Metformin hydrochloride tablets,when given 250 mg,twice a day,were as bioequivalance as sustained-release tablets given 500 mg once a day.