Abstract: OBJECTIVE To establish the method of dissolution determination and compare the dissolution profiles of the two specifications of domestic metformin hydrochlorid(250 mg and 500 mg) with those of the internationally recognized reference products, respectively. METHODS The in vitro dissolution profiles of metformin hydrochlorid tablets were tested by paddle dissolving method with the dissolution media of water, 0.1 mol·L^-1 hydrochloric acid, phosphate buffer saline(PBS) of pH 4.0 and pH 6.8. Metformin hydrochlorid in the dissolution media was determined by HPLC-UV. The dissolution similarity factors(f₂) was used to evaluate the similarity of dissolution profiles between domestic tablets(250 mg per tablet) and Glycoran(250 mg per tablet) in JP-orangebook, domestic tablets(500 mg per tablet) and Merck Santé S.A.S(500 mg per tablet) received marketing approval in Europe, respectively. RESULTS The accumulative dissolution percentages of domestic and reference products(250 mg per tablet) were both >85% at 15 min. In the dissolution medium of 0.1 mol·L^-1 hydrochloric acid, the dissolution similarity factor f₂ of domestic metformin hydrochlorid tablets(500 mg per tablet) compared with Merck Santé S.A.S was 78.5(>50). In the other dissolution media(water, PBS of pH 4.0 and pH 6.8), the f₂ of test and reference products (500 mg per tablet) was <50. CONCLUSION The dissolution profile of domestic products(250 mg per tablet) is similar with reference produces. There is a significant different dissolution profile between domestic(500 mg per tablet) and reference products in various dissolution media, except in 0.1 mol·L^-1 hydrochloric acid.