STABILITY INDICATING DEVELOPMENT AND VALIDATION FOR SIMULTANEOUS ESTIMATION OF NIRMATRELVIR AND RITONAVIR TABLET DOSAGE FORM BY USING RP-HPLC METHOD

A robust, precise, and accurate reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous estimation of Nirmatrelvir and Ritonavir in pharmaceutical tablet dosage form (Paxlovid). The chromatographic separation was performed on an Agilent C18 column (4.6 × 150 mm, 5 µm) with a mobile phase consisting of 0.01N potassium dihydrogen orthophosphate buffer (pH 3.0) and acetonitrile in the ratio 60:40, at a flow rate of 1.0 mL/min and detection wavelength of 292 nm. The retention times for Nirmatrelvir and Ritonavir were 2.121 min and 2.710 min, respectively. The method demonstrated excellent linearity (r² = 0.999), precision (RSD < 2%), accuracy (recovery ~99.3–99.7%), sensitivity (LOD 0.02–0.06 µg/mL; LOQ 0.07–0.17 µg/mL), and robustness under varied conditions. Degradation studies confirmed the method's specificity and stability-indicating capability. The validated method is suitable for routine quality control and stability analysis in pharmaceutical industries.