Physicochemical Quality of Metformin Hydrochloride tablet Brands available in Jimma Town, South west, Ethiopia

Abstract Introduction : Metformin hydrochloride, classified under the class of biguanide, is an oral anti-diabetic agent used in type 2 diabetes mellitus patients. According to the biopharmaceutical classification system, metformin is classified as a Class III drug. This study aims to compare the quality of metformin hydrochloride 500 mg tablets available in Jimma town. Methods : The physical characteristic, packaging and labeling information of samples were evaluated according to the WHO guideline. In-vitro tests such as weight variation, friability, dissolution rate, and assay were performed on six brands of metformin hydrochloride tablets available in Jimma town following method outlined in USP. Experimental data were analyzed using SPSS- 20 and one-way ANOVA. To compare the dissolution profiles of the generic products with innovator product, a model-independent approach, similarity factor (f 2 ), difference factor (f 1 ) and dissolution efficiency (DE) were used. Results : All the tested brands were in line with the WHO specifications for physical characteristics, packaging and labeling of pharmaceuticals. Insumet had percent weight deviation more than 5% and failed to comply with the USP specification for uniformity of weight. Statistically, all brands had significant difference in their mean weight variation (P<0.001). The assay results range from 95.21% to 99.61% showing that all the brands met the USP requirement. Moreover, a single point dissolution test results of the brands ranged from 85.4% to 96.7% showing compliance to USP specification. Conclusion : No brand showed any sign of counterfeit and only Insumet failed to comply with the USP specification for weight variation test. All brands complied with the United States Pharmacopeia specification for the friability, assay and single point dissolution test. Furthermore, the model-independent approach and dissolution efficiency revealed that all the brands were interchangeable with the comparator product.