Development of visible spectrophotometric methods for the analysis of favipiravir in pure drug and tablet formulation

Favipiravir is a synthetic prodrug, first discovered while assessing the antiviral activity of chemical agents active against the influenza virus. The present study is aimed at developing and validating a new colorimetric methods for its determination in both pure form and in tablet formulation. The developed method utilizes ion-pair spectrophotometry and is employed for the quantitative evaluation of the drug using the acidic dyes - methyl orange (MO) and methyl red (MR) as ion-pairing agent. The ion-pair complex of drugs with both dyes obeyed Beer’s law in the range of 10 -50 µg/ml with a acceptable correlation coefficients. Recovery by the method was also good, with a relative standard deviation (%RSD) less than 2.5%. The developed method was successfully applied to determine favipiravir in tablet formulation and was demonstrated to be accurate, precise and reproducible. It is also sufficiently sensitive and specific for the determination of the drug in bulk and formulation with satisfactory results.