Metformin

Metformin hydrochloride is an oral antihyperglycemic drug used in the management of type 2 dia-betes. Metformin hydrochloride (N, N-dimethylimidodicarbonimidic diamide monohydrochloride) is not chemically or pharmacologically related to sulfonylureas, thiazolidinediones, or -glucosidase inhibitors. It is a white to off-white crystalline compound with a molecular formula of C 4 H 12 ClN 5 (monohydrochloride) and a molecular weight of 165.63. Metformin hydrochloride is freely soluble in water and is practically insoluble in acetone, ether, and chloroform. The pKa of metformin is 12.4. The pH of a 1% aqueous solution of metformin hydrochloride is 6.68.

GLUCOVANCE is available for oral administration in tablets containing 1.25 mg glyburide with 250 mg metformin hydrochloride, 2.5 mg glyburide with 500 mg metformin hydrochloride, and 5 mg glyburide with 500 mg metformin hydrochloride. In addition, each tablet contains the following inactive ingredients: microcrystalline cellulose, povidone, croscarmellose sodium, and magne-sium stearate. The tablets are film coated, which provides color differentiation.