Development and Validation of a Reverse-Phase HPLC Method for the Simultaneous Estimation of Dolutegravir and Rilpivirine in Combined Pharmaceutical Dosage Forms

A simple, precise, and robust reverse‑phase high‑performance liquid chromatographic (RP‑HPLC) method was developed and validated for the simultaneous estimation of Dolutegravir and Rilpivirine in combined pharmaceutical dosage forms. Chromatographic separation was achieved using a Hypersil BDS C18 column (250 mm × 4.6 mm, 5 µm) with a mobile phase consisting of potassium phosphate buffer (pH 4.5) and methanol in a 50:50 v/v ratio, delivered at a flow rate of 1.0 mL/min. Detection was carried out at 257 nm. The retention times for Dolutegravir and Rilpivirine were approximately 3.30 min and 5.74 min, respectively, with resolution > 12 and tailing factors < 1.4. The method was validated as per ICH Q2(R1) guidelines and demonstrated linearity in the ranges of 10–60 µg/mL (r² > 0.99) for Dolutegravir and 5–30 µg/mL (r² > 0.999) for Rilpivirine. Accuracy, expressed as recovery, was within 98.5–101.2% for both drugs, and %RSD values for precision were < 2%. The method showed specificity with no interference from excipients and robustness under small deliberate changes in chromatographic conditions. The validated method is suitable for routine quality control analysis of fixed‑dose antiretroviral formulations.