COMPREHENSIVE ANALYTICAL METHOD DEVELOPMENT AND VALIDATION FOR STABILITY STUDY AND IMPURITY ANALYSIS OF ANTIVIRAL DRUGS USING RP-HPLC

A robust and validated stability-indicating RP-HPLC method was developed for the simultaneous estimation of Lamivudine and Tenofovir Disoproxil Fumarate in Dolutegravir, Lamivudine, and Tenofovir (DLT) combination tablets. Chromatographic separation was achieved on a Kinetex Biphenyl column (100 × 4.6 mm, 2.6 μm) using a gradient elution with buffer and an organic phase consisting of acetonitrile, methanol, and isopropyl alcohol. Detection was performed at 260 nm with a total run time of 97 minutes. The method was validated according to ICH guidelines and demonstrated specificity, linearity (correlation coefficient R² = 1.000 for both analytes), precision, accuracy, robustness, and adequate limits of detection and quantification. Forced degradation studies under acidic, basic, oxidative, thermal, humidity, and photolytic conditions confirmed that the method can reliably separate analytes from their degradation products, with no interference from excipients. The developed method proved to be selective, precise, and robust, making it suitable for routine quality control and stability testing of DLT tablets.