A comprehensive review on RP-HPLC methodologies for combined quantification of selected drugs

Abstract

The co-administration of Sitagliptin, a DPP-4 inhibitor, and Simvastatin, an HMG-CoA reductase inhibitor, is widely used in the management of diabetic dyslipidaemia. Accurate and reproducible quantification of both drugs in combined tablet formulations is essential to ensure product quality and therapeutic efficacy. This review provides a comprehensive overview of reverse-phase high-performance liquid chromatography (RP-HPLC) method development and validation strategies for the simultaneous estimation of Sitagliptin and Simvastatin in pharmaceutical dosage forms. Optimized chromatographic conditions were achieved using a C18 column with an acetonitrile–phosphate buffer mobile phase under isocratic elution. Detection was performed at a wavelength of 254–260 nm, with retention times around 3.2 minutes for Sitagliptin and 5.5–6.0 minutes for Simvastatin. The method was validated according to ICH Q2(R1) guidelines and exhibited excellent linearity (5–100 µg/mL, r² > 0.999), accuracy (98–102%), and precision (%RSD < 2%). Specificity tests confirmed the absence of interference from excipients, and the method demonstrated robustness and suitable sensitivity with low LOD and LOQ values. Forced degradation studies further confirmed the method’s stability-indicating capability, especially noting Simvastatin’s susceptibility to acidic and oxidative stress. This validated RP-HPLC method offers a reliable, efficient, and reproducible approach for the simultaneous determination of Sitagliptin and Simvastatin in routine quality control and regulatory analysis, supporting pharmaceutical development and compliance.