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 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