Patent ID: 8309125

Claim:
A method for preparing a sustained release oral tablet comprising: a) forming a controlled release metformin hydrochloride tablet comprising 500 mg to 1000 mg of metformin; b) preparing an immediate release coating solution comprising: i) pioglitazone hydrochloride; ii) water; iii) an organic solvent selected from the group consisting of acetone, isopropyl alcohol, methanol or ethanol; iv) a binder; v) optionally a surfactant; vi) optionally a pore forming agent wherein the ratio of water to organic solvent is 50:50 to 2:98 and the ratio of binder to pioglitazone hydrochloride is 1:9 to 1:11; c) applying the immediate release coating solution to the controlled release metformin hydrochloride tablet so that when tested in a United States Pharmacopeia (USP) Type 2 apparatus at 75 rpm in 900 ml of simulated intestinal fluid (pH 7.5 phosphate buffer) and at 37° C., not less than 75% of the pioglitazone hydrochloride is released from the sustained release tablet in 30 minutes.