Development and Validation of RP-HPLC and HPTLC Methods for Simultaneous Estimation of Sitagliptin Phosphate and Metformin Hydrochloride in Bulk and Dosage form

Two simple, specific, accurate and precise methods, namely, reverse phase high performance liquid chromatography and high performance thin layer chromatography were developed for simultaneous estimation of Sitagliptin phosphate and Metformin HCl in tablet dosage forms. For the HPLC method, Phenomenex C column (250 mm × 4.6 mm, 5μm) in gradient mode, with mobile phase containing acetonitrile: phosphate buffer 0.03M in proportion of 70:30 v/v, 18 pH 3.5 adjusted with orthophosphoric acid at a flow rate of 1mL/min was used, and effluent was monitored at 218 nm. The retention time of Sitagliptin phosphate and Metformin HCl was 5.27 and 1.93 min respectively. For the high performance thin layer chromatographic method separation was achieved on silica gel 60F 254 HPTLC plates with water-methanol-ammonium sulphate, 4.5 + 4.5 + 1.5 (v/v/v) as mobile phase. The detection of spot was carried out at 254 nm. The R value f was found to be 0.68 and 0.59 for Sitagliptin phosphate and Metformin HCl respectively. The methods were validated in terms of linearity, accuracy and precision. The proposed methods were successfully used for estimation of Sitagliptin phosphate and Metformin HCl in tablet dosage form.