Method for separating and detecting impurities in metformin hydrochloride and vildagliptin tablets

The invention relates to a liquid chromatography separation and detection method for impurities in metformin hydrochloride and vildagliptin tablets. The method comprises the steps that: a C18/SCX mixed column is adopted, and a 0.025-0.035 mol/L potassium dihydrogen phosphate aqueous solution with a pH value of 4.5-5.0 is adopted as a mobile phase A; acetonitrile is adopted as a mobile phase B forgradient elution, wherein the detection wavelengths are 210 nm (vildagliptin) and 208 nm (metformin hydrochloride), the column temperature is 25-35 DEG C, the flow rate is 0.8-1.2 mL/min, and the sample size is 20-30 mu L. The method can completely separate metformin hydrochloride impurities A, B, C, D and E and vildagliptin impurities G, H, I and J recorded in European pharmacopoeia at the same time, is simple, precise and high in sensitivity, and can further be used for detecting metformin hydrochloride bulk drugs, metformin hydrochloride preparations, vildagliptin bulk drugs and vildagliptin preparation related sub