PROBLEM TO BE SOLVED : To provide effective sustained release formulations of omecamtiv mecarbil, which is a drug for acute heart failure and chronic heart failure. SOLUTION : A pharmaceutical formulation comprises : a drug layer, comprising omecamtiv mecarbil; a sweller layer; and a semi-permeable membrane coating having at least one delivery port. Preferably, the drug layer comprises a drug layer polymer and a lubricant; the sweller layer comprises a sweller layer polymer, an osmotic agent, a diluent, and a lubricant; and the semi-permeable membrane coating comprises an insoluble polymer and a pore forming polymer. SELECTED DRAWING : None COPYRIGHT : (C)2019, JPO&INPIT