COMPARATIVE EVALUATION OF PHYSICOCHEMICAL PROPERTIES OF SOME COMMERCIALLY AVAILABLE BRANDS OF METFORMIN HCL TABLETS MARKETED IN SUDAN

The pharmaceutical equivalence of five different brands of metformin hydrochloride 500 mg tablets available in the Sudanese market was evaluated using a number of official and non-official pharmacopoeial tests; which included determination of assay of content, evaluation of uniformity of weight, friability, hardness, thickness, disintegration time and dissolution tests. The dissolution profiles of the generic brands and innovator were studies and compared using similarity factor f2 and difference factor f1. The results showed that all the five tested brands complied with the requirements of weight variation test, thickness test, friability, disintegration time test and dissolution test. However, the assay test showed that all brands complied with pharmacopeias specifications except for brand (B) which failed to pass the test. Also regarding the crushing stress (Hardness) test, four brands complied except brand (D) which failed to pass the non-official test. All brands showed good release profile with f2 values greater than 50 and difference factor f1 lower than 15 when compared with the innovator drug (A). It concluded that from all the tested brands of metformin hydrochloride tablets, only brands A, C, D and E could be considered biopharmaceutically and chemically equivalent and therefore can be used interchangeably in the clinical practice.