A method of preparing a pharmaceutical dosage form having a first and second active drug, comprising(a) forming a controlled release core comprising metformin or a pharmaceutically acceptable salt thereof and at least one pharmaceutically acceptable excipient(b) coating a coating solution on said controlled release core to form an immediate release coating, said coating solution comprising:(i) pioglitazone or a pharmaceutically acceptable salt thereof(ii) water(iii) an organic solvent(iv) a binder(v) optionally a surfactant(vi) optionally a pore forming agentwherein the ratio of water to organic solvent is 50:50 to 2:98, and the ratio of binder to pioglitazone or the salt thereof is 1:9 to 1:11wherein said dosage form releases not less than 75% of the pioglitazone or the salt thereof from the dosage form within 0.5 hour 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.
