Solution A 1 volume of acetonitrile

Solution A 1 volume of acetonitrile R1 and 19 volumes of 0.1% v/v of orthophosphoric acid. (1) Add 150 mL to a number of whole tablets containing the equivalent of 250 mg of sitagliptin and shake until the tablets are dispersed. Dilute to 500 mL, mix and filter. Further dilute to produce a solution expected to contain 0.01% w/v of Metformin Hydrochloride. (2) 0.01% w/v of metformin hydrochloride BPCRS. (3) Prepare a solution of sitagliptin phosphate monohydrate EPCRS in solution (2) at a concentration of sitagliptin equivalent to that expected in solution (1). Chromatographic conditions The chromatographic conditions described under Related substances for metformin may be used.