RP-HPLC Method Development and Validation for the Simultaneous Estimation of Sitagliptin and Simvastatin in Pharmaceutical Formulation

Analytical methods are required to characterize drug substance and drug product composition during all phases of pharmaceutical development. Early phase methods must support changes in synthetic routes and dosage form and elucidate the structures and levels of impurities. In later phases, goals change to the development of rapid and robust methods for release and stability evaluation. Hence we attempt to develop a simple accurate RPHPLC method for the simultaneous estimation of Simvastatin a hypo-lipidemic drug and Sitagliptin an oral antihyperglycemic drug in pharmaceutical formulations. The quantification was carried out on Prontosil ODS C18 Column (250 x 4.6 mm and 5μm) in isocratic mode, with mobile phase consisting of Methanol: Water: Acetonitile in the ratio of 50:30:20 (v/v/v).The mobile phase was pumped at a rate of 0.80ml/min and the detection was carried out at 261nm and the linearity was found to be in the range of 2 to 12μg/ml for Simvastatin and 5-30μg/ml for Sitagliptin. The regression equation was found to be y = 25876x + 41754 (r²=0.999) for Simvastatin and y = 18801x + 12921 (r² = 0.998) for Sitagliptin. The % recovery values were found to be in the range of 98-102% for both the drugs. LOD and LOQ value was found to be 0.005μg/ml, 0.016μg/ml for Sitagliptin and 0.025μg/ml, 0.08μg/ml for Simvastatin respectively. The proposed method was validated for accuracy and precision. Statistical analysis proves that the method was found to be simple, precise, accurate, rapid and reproducible and can be used for the routine simultaneous determination of Simvastatin and Sitagliptin in bulk drug and in pharmaceutical formulations.