DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR THE SIMULTANEOUS ESTIMATION OF NIRMATRELVIR AND RITONAVIR IN PHARMACEUTICAL DOSAGE FORMS

Abstract

A simple, accurate, and precise reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous estimation of Nirmatrelvir and Ritonavir in tablet dosage forms. Chromatographic separation was achieved using an Inertsil ODS-4 column (150 mm × 4.6 mm, 5 μm) with a mobile phase consisting of 0.1% orthophosphoric acid buffer and acetonitrile in the ratio 30:70 (v/v), delivered at a flow rate of 1.0 mL/min. Detection was carried out at 254 nm, and the column temperature was maintained at 30°C. The retention times for Nirmatrelvir and Ritonavir were found to be 2.4 minutes and 3.8 minutes, respectively. The method was validated in accordance with ICH Q2(R1) guidelines for parameters such as system suitability, linearity, precision, accuracy, sensitivity, robustness, and assay. The %RSD for repeatability and intermediate precision was less than 2%, confirming the method's precision. The method showed excellent linearity with correlation coefficients (r²) of 0.999 for both analytes. The recovery values ranged from 98.11% to 101.5%, confirming accuracy. LOD and LOQ were found to be 0.24 μg/mL and 0.72 μg/mL for Nirmatrelvir, and 0.14 μg/mL and 0.41 μg/mL for Ritonavir, respectively. The validated method was successfully applied to the assay of marketed tablet formulations, confirming its suitability for routine quality control analysis.