Comparison of the Physicochemical Properties and Release Profiles of Metformin Tablets of Eight Different Brands Available in the Northern Cyprus Pharmaceutical Market

Abstract

Objective: In the study, it was aimed to compare the physicochemical and in vitro dissolution parameters of metformin hydrochloride (MET) tablet brands from Northern Cyprus to evaluate the pharmaceutical equivalence.Methods: Seven brands of MET tablets which were bought from community pharmacies were compared and evaluated with the innovative product Glucophage (R). The impurity of MET contained in the sample tablets was determined using Fourier transform infrared spectroscopy. Pharmacopoeia tests were used to evaluate the physicochemical equivalence of the tablets. In vitro dissolution test was performed and dissolution data were analyzed including dissolution difference (f1) and similarity factors (f2) were evaluated. In addition, the release kinetics of selected MET tablets were examined with a release kinetics software (KinetDS3).Results: All the tablet brands complied with the official specifications for uniformity of weight hardness and disintegration. Brand MF failed the friability test (> 1%); while brands MC, MF and MG failed the content uniformity (assay) test (< 95%). Difference (f1) and similarity factors (f2) of all brands were calculated in pH 6.8 buffer medium and evaluated with reference to the innovative brand. The facts that MB's f1 value (15.45) was greater than 15 and that the f2 values of MB and MF (48.57, 47.13, respectively) were less than 50 indicated that the dissolution profiles of MB and MF formulations were different from the dissolution profile of the innovative brand.