Determination of Favipiravir that is one of the drugs for COVID-19 treatment and its degradation impurities by HPLC

Favipiravir is one of the active pharmaceutical ingredients used in the treatment of the Covid-19 epidemic that started in 2019 and is still continuing all over the world. In the literature researches, no HPLC method was found to support the determination of this active substance and its impurities in pharmaceutical preparations in tablet form with detailed degradation studies. In this thesis, an analysis method was developed for the simultaneus analysis of favipiravir and its impurities, and the method was validated. In the developed method, Kinetex® EVO C18 (250 x 4.6 mm, 5 µm, 100Å) column and a mixture of 10 mM KH2PO4 buffer (pH = 3.0) and acetonitrile (90:10; v / v) were used as the stationary and mobile phase.Chromatographic separations were carried out at 30 oC column temperature and samples were monitored by a UV-Visible detector with a wavelength of 222 nm at 0.5 ml / min flow rate. Total analysis time was 25 minutes, Favipiravir retention time was approximately 9 minutes; The retention times of major impurities formed under alkaline, acidic, oxidative conditions were observed at about 4., 5., 7 and 12 minutes (RRT 0.51, 0.54, 0.76, 1.31). According to validation results, the linearity range was obtained as 0.00003 – 0.00075 mg/ml, the limit of quantitation (LOQ) and the limit of dedection (LOD) were 0.00003 mg/ml and 0.00001 mg/ml, respectively. Percentage relative standard deviation values (% RSD) obtained in intra-day and between day repeatability studies were determined as 0.17% and 0.28%, respectively, and the average recovery value was found 99.46%. This validated method, has been successfully applied to the determination of all possible degradation impurities of Favipiravir that increase under stress conditions such as high temperature, humidity and photodegradation from tablet form. The developed method is extremely suitable for the routine analysis of this drug used in the treatment of the Covid-19 outbreak, especially in terms of speed and convenience.