Carry out the method for liquid chr

Carry out the method for liquid chromatography, Appendix III D, using the following solutions. Solution A 20 volumes of 0.1% v/v of orthophosphoric acid and 80 volumes of methanol. Solution B 5 volumes of acetonitrile R1 and 95 volumes of 0.1% v/v of orthophosphoric acid. (1) Add 150 mL of solution A to a number of whole tablets containing 2 g of Metformin Hydrochloride and shake until the tablets are dispersed. Dilute to 500 mL with solution A, mix and filter. Dilute 1 volume of the resulting solution to 20 volumes with solution B. (2) Dilute 1 volume of solution (1) to 100 volumes and dilute 1 volume of the resulting solution to 10 volumes with solution B. (3) To 20 mL of 0.02% w/v of metformin hydrochloride BPCRS in solution B, add 0.1 mL of 0.1m sodium hydroxide, heat at 80° for 2 hours, allowto cool to room temperature and add 3 mL of orthophosphoric acid (generation of impurities 6 and 7). Add 2 mL of 0.01% w/v of sitagliptin phosphate monohydrate EPCRS in solution B and mix.