Evaluation of Dissolution Profiles of Generic Metformin Tablets Available in Abuja Using USP Apparatus II

Metformin hydrochloride is the first-line oral antidiabetic agent recommended for the management of Type 2 diabetes mellitus. With the rising prevalence of diabetes across Nigeria, generic metformin tablets are widely dispensed in public and private healthcare facilities in the Federal Capital Territory, Abuja. The bioavailability of these tablets is critically dependent on their in vitro dissolution performance. This study evaluated and compared the dissolution profiles of five generic metformin 500 mg tablet brands commonly dispensed in Abuja pharmacies against a reference branded product using USP Apparatus II at 75 rpm in 900 ml of 0.1 M hydrochloric acid at 37 degrees Celsius. Drug content was determined by UV spectrophotometry at 232 nm. Dissolution efficiency and mean dissolution time were calculated, and profiles were compared using the similarity factor (f2). Three of the five generic brands demonstrated dissolution profiles similar to the reference product, with f2 values above 50. Two brands showed significantly slower dissolution, with less than 70% drug released at 30 minutes, below the compendial requirement. Tablet hardness and disintegration time were inversely correlated with dissolution rate. These findings indicate variable quality among generic metformin products available in Abuja and underscore the need for stricter therapeutic equivalence standards in generic medicine regulation. Keywords: metformin tablets, dissolution profile, generic drugs, USP Apparatus II, Abuja.