Stability Indicating Liquid Chromatographic Method for Determination of Lamivudine and Tenofovir Disoproxil Fumarate in Fixed Dose Combination Formulations

Abstract

This study describes the development and validation of a stability indicating high performance liquid chromatographic method for the analysis of lamivudine and tenofovir disoproxil fumarate and their degradants. The method uses a Reprosil®-pur basic C18 column (250 mm × 4.6 mm, 5 µm) maintained at 30°C, methanol and a mixture of buffers (2.3 g/L ammonium dihydrogen phosphate and 1.32 g/L of diammonium hydrogen phosphate, pH 3.9) for gradient elution at a flow rate of 1.0 mL/min, and UV detection at 270 nm. Good separation of lamivudine and tenofovir disoproxil fumarate and their potential impurities was achieved. The stability indicating ability of the developed method was validated by subjecting both active ingredients to hydrolytic and oxidative stress conditions and separating the degradation products from their respective intact drugs. The calibration curve was linear over the 80-120 μg/mL concentration range for both active ingredients with r2> 0.99. A recovery rate of 99.8 % for lamivudine and 99.3 % for tenofovir disoproxil fumarate confirmed the accuracy of the method for the simultaneous determination of both drugs in the fixed-dose combination.