Simultaneous Estimation of Vildagliptin and Linagliptin in Bulk and Pharmaceutical Formulation by Reverse Phase High Performance Liquid Chromatography Method

Abstract

A novel and simple RP-HPLC method was developed and validated for the simultaneous estimation of Vildagliptin and Linagliptin in combined pharmaceutical dosage forms. The method employed a Kromasil C18 column with a mobile phase of orthophosphoric acid buffer and methanol (70:30 v/v), at a flow rate of 1 ml/min, with detection at 292 nm. Validation according to ICH Q2B guidelines demonstrated excellent accuracy, precision, linearity, robustness, sensitivity, and specificity. The method showed linear responses between 1–5 µg/ml for both analytes, with correlation coefficients greater than 0.999. Limits of detection were 0.89 and 0.71 µg/ml, and limits of quantification were 2.99 and 2.39 µg/ml for Vildagliptin and Linagliptin, respectively. Precision studies indicated %RSD values below 0.36%, confirming repeatability. Recovery studies yielded 97–103%, demonstrating accuracy in the presence of formulation excipients. Robustness testing revealed minimal impact of flow rate and temperature variations on retention times and assay results. Application to commercial tablets showed mean assay values close to 100%, with well-resolved symmetrical peaks. This validated RP-HPLC method is accurate, precise, rapid, and economical, suitable for routine quality control, stability studies, and bioequivalence assessments of combined Vildagliptin and Linagliptin 
formulations. Its robustness and simplicity make it an effective analytical tool for pharmaceutical analysis and regulatory compliance.