Novel environment friendly TLC-densitometric method for the determination of anti-coronavirus drugs "Remdesivir and Favipiravir": Green assessment with application to pharmaceutical formulations and human plasma.

A great demand for discovering new therapeutic solutions has been considered all over the world for managing the rapidly progressing COVID-19 pandemic. Remdesivir (REM) and Favipiravir (FAV) are introduced as promising newly developed antiviral agents against the corona virus as evidenced by the clinical findings. Hence, the optimization of an analytical method for their simultaneous determination acquires potential importance in quality control labs and further confirmatory investigations. Herein, a green, sensitive, and selective densitometric method has been proposed and validated for determination of REM and FAV in pharmaceutical formulations and spiked human plasma on normal phase TLC plates. A solvent mixture of ethyl acetate-methanol-ammonia (8:2:0.2 by volume) has been chosen as developing mobile phase system. Well resolved spots have been detected at 235 nm with retardation factors (R) of 0.18 and 0.98 for REM and FAV, respectively. A validation study has been carried out in the light of ICH guidelines. Remdesivir and FAV have shown excellent sensitivities with quantitation limits down to 0.12 and 0.07 μg/band, respectively. The developed method has been successfully applied to tablet formulations and spiked plasma with excellent recoveries ranged from 97.21 to 101.31%. The greenness of the method has been evaluated using the standards of greenness profile and Eco-Scale. It has passed the four greenness profile quadrants and achieved 80 score in Eco-Scale.