Unlocking Molnupiravir Analysis: A Validated Rp-Hplc Approach

Abstract

A simple, robust, and validated reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed for the quantitative analysis of Molnupiravir in its active pharmaceutical ingredient (API) form. Chromatographic separation was achieved using an Inertsil C8 column (150 × 4.6 mm, 5 μm) with an isocratic mobile phase comprising potassium dihydrogen phosphate buffer (pH 4.1) and methanol in an 80:20 ratio (v/v). The flow rate was maintained at 1.0 mL/min, and detection was performed at 275 nm. The method showed excellent linearity across the concentration range of 50–150% with a correlation coefficient (r²) of 0.999. Accuracy, expressed as recovery, ranged from 98.08% to 100%, and precision was confirmed by a %RSD of less than 0.2%. The method demonstrated high sensitivity with a limit of detection (LOD) of 0.478 µg/mL and a limit of quantification (LOQ) of 1.592 µg/mL. It remained stable and specific under various forced degradation conditions, including acidic, alkaline, oxidative, photolytic, and thermal stress, establishing its stability-indicating capability. Robustness and ruggedness studies confirmed the method's reliability across small deliberate variations in chromatographic conditions and different analysts and instruments. Validated in accordance with ICH Q2(R2) guidelines, this method is suitable for routine quality control and regulatory analysis of Molnupiravir in bulk drug substances. Given the critical role of Molnupiravir in COVID-19 treatment, the developed method ensures consistent drug quality and supports safe and effective pharmaceutical formulations.