A Rapid, Simplified and Validated Reverse Phase Liquid Chromatography Method for Quantitation of Molnupiravir and Its Generic Versions

Molnupiravir, an orally active RdRp inhibitor, though originally developed to use against influenza, has become a promising therapeutic candidate for COVID-19 infection by acting as prodrug of the nucleoside analog b-d-N4-hydroxycytidine (NHC or EIDD- 931) in the isopropyl ester form. Accordingly, it has been approved by MHRA, UK in November 2021 to use against COVID-19. This work presents the development and validation of a high-performance liquid chromatography (HPLC) method for the rapid and accurate assessment of molnupiravir. The objective of this approach is to ensure the quality control of Lagevrio® capsules and their generic versions available in Bangladesh. The separation was carried out by isocratic elution through C18 column (4.6 mm × 250 mm i.d., 5 µ particle size) at 40 °C temperature at a constant flow rate of 1.0 mL/min using acetonitrile and 1% orthophosphoric acid as buffer (20:80, v/v). A 10 mL sample was injected and elution was monitored at 210 nm wavelength. The calibration curve over the concentration range of 80-120% were found to be linear (r2 = 0.9998), the %RSD for intra-day (0.31%) and inter-day (0.73%) precision indicate good precision where %recovery was found in the acceptable range of 99.9-100.4% as per ICH guidelines. The method was successfully applied to commercial pharmaceuticals, Lagevrio® and its generic versions and and the results were found to be consistent with the label claims (95-105%).