Bioequivalence and Safety Assessment of Two Formulations of Metformin Hydrochloride Sustained-Release Tablets (Yuantang® SR and Glucophage® XR) Under Fed Conditions in Healthy Chinese Adult Subjects: An Open-Label, Two-Way Crossover, Sequence Randomized Phase I Clinical Trial

This open-label, crossover Phase I trial evaluated the bioequivalence and safety of a generic 500-mg metformin hydrochloride sustained-release tablet against the originator formulation (Glucophage XR) in 36 healthy Chinese adults under postprandial conditions. Plasma metformin was measured by LC-MS/MS and pharmacokinetic parameters analyzed using Phoenix WinNonlin. The 90% confidence intervals for AUC and Cmax adjusted geometric mean ratios fell within the standard bioequivalence range, and no serious adverse events occurred. The generic sustained-release metformin formulation was confirmed to be bioequivalent and well tolerated compared with the originator product under postprandial conditions.