Bioequivalence study of metformin HCL XR caplet formulations in healthy Indonesian volunteers

Aim: Determination of the bioequivalence of two metformin HCl (750 mg) caplet formulations (Glucophage XR® from Bristol-Myres Squibb Company, Indonesia as a reference formulation and Glumin XR® from Ferron Par Pharmaceutical, Indonesia as a test formulation). Material and method: The study was conducted according to an open label, randomized, Two-period crossover design with a 1 week washout period. Twelve volunteers participated and all completed the study successfully. Blood samples were obtained prior to dosing and at 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; 4.0; 6.0; 8.0; 10.0; 14.0; 18.0; 24.0 and 30.0 hours after drug administration. Plasma will be separated by centrifuge and stored frozen at -20 degree Celcius. Plasma concentration of metformin HCl was monitored using high performance liquid chromatography (HPLC) with photo diode array (PDA) detection over a period of 30 hours after administration. The pharmacokinetics parameter AUC 0-30 h, AUC 0-∞ and Cmax were tested for bioequivalence after log transformation of data and ratios of Tmax were evaluated non parametrically. Result: The point estimates and 90% confidence interval for AUC 0-30 h, AUC 0-∞ and Cmax were 101.88% (94.78-109.50%), 101.50% (93.77- 109.87%) and 105.93% (97.00-115.98%), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and The US Food and Administration Guidelines. Conclusion: These results indicate that two medications of metformin HCl are bioequivalent, thus, may be prescribed interchangeably.