Abstract: AIM: To study the bioequivalence of two metformin hydrochloride sustained-release tablets in Chinese healthy subjects.  METHODS: A randomized, open-label, two-period, crossover study design was adopted in the study. In fasting test 36 and in fed test 23 healthy subjects were given a single oral dose of metformin hydrochloride sustained-release tablet (0.5 g). The concentration of metformin in plasma was measured by HPLC-MS/MS. The pharmacokinetic parameters were calculated by WinNonlin 7.0 program, and statistical analysis were performed by using SAS9.4 statistics software. RESULTS: In the fasting test, the pharmacokinetic parameters of metformin of the test (T) and reference(R) preparation were as follow: Cmax were (700.6±191.1) and (694.5±169.2) ng/mL, AUC0-t were (4 858.7±1134.3) and (4 809.3±1 188.6) ng·h·mL-1, AUC0-∞ were (5 010.9±1 114.5) and (4 962.5±1 184.1) ng·h·mL-1. In the fed test, the pharmacokinetic parameters of T and R were as follow: Cmax were (738.4±121.9) and (738.0±128.7) ng/mL, AUC0-t were (7 558.3±1 271.8) and (7 761.5±1 486.0) ng·h·mL-1, AUC0-∞ were (7 713.7±1 275.5) and (7 924.3±1 506.30) ng·h·mL-1. In fasting condition, the 90% confidence interval (90%CI) of Cmax, AUC0-t and AUC0-∞ of metformin were 92.16%-111.56%, 93.36%-110.93% and 93.58%-110.39%. In fed condition, the 90%CI of Cmax, AUC0-t and AUC0-∞ of metformin were 96.74%-105.10%, 94.94%-101.71% and 95.00%-101.68%. All datas were in the area of 80.00%-125.00%. CONCLUSION: The two metformin hydrochloride sustained-release tablets were bioequivalent.

Key words: metformin hydrochloride sustained-release tablets, bioequivalence, pharmacokinetics