Quantitative RP-HPLC analysis of cabotegravir and rilpivirine in bulk and pharmaceutical dosage forms: development and validation

This study details the development and validation of a robust reverse-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous quantification of Cabotegravir and Rilpivirine in pharmaceutical dosage forms. The method was designed for precision, accuracy, and simplicity, employing an Inertsil ODS column (200 × 4.6 mm, 5 µm) with an isocratic mobile phase of 0.1% ortho-phosphoric acid and acetonitrile (80:20 v/v). Chromatographic separation was achieved at a flow rate of 1.5 ml/min, with detection at 230 nm. The method demonstrated linearity within concentration ranges of 10–50 µg/ml for Cabotegravir and 5–25 µg/ml for Rilpivirine, with correlation coefficients exceeding 0.999, indicating excellent linear relationships. Validation followed International Council for Harmonisation (ICH) guidelines, assessing precision, accuracy, specificity, robustness, and stability. The % relative standard deviation (%RSD) values for both drugs remained within acceptable limits, confirming high repeatability and reproducibility. Robustness was tested by varying the flow rate and mobile phase composition, showing minimal impact on method performance. Stability studies under acidic, basic, and oxidative conditions confirmed the method’s capability to quantify degradation products effectively. This validated RP-HPLC method serves as a reliable and efficient tool for quality control and stability testing of Cabotegravir and Rilpivirine in bulk and formulated products, ensuring compliance with pharmaceutical standards and therapeutic efficacy assessment.