A new, simple, accurate, precise and rapid reversed-phase high performance liquid chromatographic (RP-HPLC) method has been developed and subsequently validated for the simultaneous estimation of Sitagliptin phosphate and Metformin hydrochloride in pure and dosage forms. The proposed method is based on the separation of the two drugs in reversed-phase mode using Kromasil 100-5C18 Column[ 250mm × 4.6mm] . The optimized mobile phase consisted of phosphate buffer (pH 4): acetonitrile in the ratio 50:50 v/v, flow rate was set at 1.0 mL/min and UV detection was set at 258 nm. The retention times of Metformin hydrochloride and Sitagliptin phosphate were 1.88 and 3.55 respectively. The method was validated according to ICH guidelines. It was found to be accurate and reproducible. Linearity was obtained in the concentration range of 100-500μg/ml for Metformin hydrochloride and 10-50μg/mL for Sitagliptin phosphate. Mean percent recovery of samples at each level for both drugs were found to be 99.78% for Metformin hydrochloride and 99.38% for Sitagliptin phosphate. The proposed method can be successfully applied in the quality control of bulk and Pharmaceutical dosage forms
