Development and validation of stability indicating HPLC method for favipiravir used in the treatment of the Covid-19 disease

Background and Aims: Favipiravir (FAV) is one of the active pharmaceutical ingredients used in the treatment of patients suffering from Covid-19. The epidemic started in 2019 and is still continuing all over the world. In this study, an analysis method was developed and validated for the simultaneous analysis of FAV and its degradation impurities. Methods: The stationary phase of the developed method was determined using Kinetex[R] EVO C18 column and the mobile phase was pH 3.0 phosphate buffer:acetonitrile (90:10; v/v). Chromatographic separations were carried out at 30 [degrees]C column temperature and samples were monitored by a UV-Visible detector with a wavelength of 222 nm at 0.5 mL/min flow rate. Results: Total analysis time was 25 minutes; FAV 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), respectively. According to the validation data, the linearity range was obtained as 0.030 - 0.750 [micro]g/mL, the limit of quantitation and the limit of detection were 0.030 [micro]g/mL and 0.010 [micro]g/mL, respectively. Percentage relative standard deviation values 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 to be 99.46%. Conclusion: This validated method has been successfully applied to the determination of all possible degradation impurities of FAV that increase under stress conditions such as high temperature, humidity and photodegradation from tablet form. The developed HPLC method is extremely suitable for the routine analysis of this drug used in the treatment of the Covid-19 disease, especially in terms of speed and convenience. Keywords: Covid-19, favipiravir, stability indicating method, HPLC, validation