A NOVEL RATIO DIFFERENCE SPECTROPHOTOMETRIC METHOD FOR THE SIMULTANEOUS DETERMINATION OF MOLNUPIRAVIR AND FAVIPIRAVIR IN BINARY MIXTURE

Objective: A ratio difference spectrophotometric method was developed for the determination of molnupiravir (MNP) and favipiravir (FVP) in binary mixtures, two antiviral agents of significance in COVID-19 therapy, and its applicability to the analysis of real samples was evaluated. Material and Method: Measurements were recorded with a UV-VIS spectrophotometer in the 200–300 nm wavelength range against water as a blank solution. While preparing the ratio spectra, the binary mixtures were divided by spectra of 5 µg/ml FVP and 5 µg/ml MNP, respectively. Calculations were performed using the differences in absorbance at wavelengths of 265 nm to 280 nm for MNP and 220 nm to 250 nm for FVP in the ratio spectra. Result and Discussion: The developed method exhibited linearity in the concentration range of 2.5–30.0 µg/ml for MNP and 2.5–30.0 µg/ml for FVP, and the detection limits were calculated as 99 ng/ml and 109 ng/ml, respectively. Recovery studies were performed on MNP capsules and FVP tablets, and the average recovery values were calculated as 99.82% and 100.30%, respectively.