STABILITY-INDICATING REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR THE SIMULTANEOUS ESTIMATION OF SELECTED DRUGS IN BULK AND FORMULATIONS WITH GREENNESS ASSESSMENT USING GREEN ANALYTICAL PROCEDURE INDEX

Objectives: A comprehensive, verified, and dependable reversed-phase high-performance liquid chromatography method was created to assess velpatasvir and sofosbuvir in bulk and fixed-dose combo tablets. Methods: The analysis was performed using a Waters Alliance 2695 high-performance liquid chromatography (HPLC) system equipped with an autosampler, a 2998 PDA detector, and Empower 2 software. Chromatographic separation was achieved on a BDS Hypersil C8 column (4.6 × 50 mm, 5 μm; Thermo Scientific). The mobile phase consisted of a 50:50 (v/v) mixture of potassium dihydrogen phosphate buffer (pH 3.5, adjusted with 0.1% orthophosphoric acid) and HPLC-grade acetonitrile. The detection wavelength was set at 288 nm, and the flow rate was maintained at 1.0 mL/min. Results: In the concentration range of 2.5–15 μg/mL for velpatasvir and 20–120 μg/mL for sofosbuvir, the methodology consistently exhibits high correlation coefficients (R²) of 0.999, indicating exceptional linearity. Sofosbuvir exhibited a higher degree of precision than velpatasvir, with a recovery rate of 100.11% in contrast to 99.31%. To verify the precision and robustness (with a %RSD of