Bioequivalence of a generic metformin tablet preparation.

OBJECTIVE: The bioavailability of a generic preparation of metformin (Diabetmin from Hovid Sdn Bhd) was evaluated in comparison with a proprietary product (Glucophage from Lipha Pharma Ltd., UK). PATIENTS AND METHODS: Twenty-four healthy male volunteers participated in the study conducted according to a two-way crossover design. The bioavailability was compared using the parameters total area under the plasma concentration-time curve (AUC0-infinity), peak plasma concentration (Cmax and time to reach peak plasma concentration (Tmax). RESULTS: No statistically significant difference was observed between the values of the two products in all three parameters. Moreover, the 90% confidence interval for the ratio of the logarithmic-transformed AUC0-infinity and Cmax values of Diabetmin over those of Glucophage was found to lie between 0.94-1.03 and 0.94-1.06, respectively, being within the acceptable bioequivalence limit of 0.80-1.25. CONCLUSION: These findings indicate that the two preparations are comparable in the extent and rate of absorption. In addition, elimination rate constant (k(e)) and apparent volume of distribution (Vd) were calculated. There was no statistically significant difference between the values of the two preparations in the k(e) and Vd. Moreover, the values are comparable to those reported in the literature.