Rp-Hplc Method for Simultaneous Estimation of Vildagliptin and Metformin in Bulk and Pharmaceutical Formulations

Background: Combination therapy of vildagliptin and metformin provides a comprehensive effect on cardiovascular risk factors in the form of preventing hyperinsulinemia and reducing insulin resistance. Objective: To develop a simple, fast, precise, accurate, sensitive RP-HPLC method for simultaneous estimation of metformin and vildagliptin in pure and tablet dosage forms. Method: The mobile phase, a mixture of acetonitrile, methanol and water (15:60:25v/v) pumped at a flow rate of 1.0 ml/min through the column (C18; 5μ, 4.6 X 250 mm, Hypersil) at 35oC temperature. The mobile phase was degassed before use under vacuum by filtration through a 0.2μ nylon membrane. Concentrations were measured at 278 nm by a UV detector at a sensitivity of 20 μl. Results: The linearity lies between 1-5 μg/ml for metformin and 1-5 μg/ml for vildagliptin in the method. The correlation coefficient (r2) was found to be 0.982 and 0.998 for Metformin and vildagliptin, the limit of detection and limit of quantification were found to be 0.617and 1.87 μg/ml for metformin and 0.154 and 0.468 μg/ml for vildagliptin, respectively. The results of the analysis have been validated statistically by recovery studies as per International Conference on Harmonization guidelines. Conclusion: The method showed good reproducibility and recovery with %RSD <2. Hence, the method was found to be rapid, specific, precise, and accurate and can be successfully applied for the routine analysis of metformin and vildagliptin in the pure and combined dosage form.