Ekawan Yoosakul, Anas Sunhem, Vipada Khaowroongrueng*, Lalinthip Saeaue, Busarat Karachot, Isariya Techatanawat, Porranee Puranajoti, Praphassorn Surawattanawan
Favipiravir is a broad spectrum antiviral against RNA viruses. It has been considered as a promising treatment strategy for a pandemic of Coronavirus Disease 2019 (COVID-19). During this urgent need, the Government Pharmaceutical Organization (GPO), Thailand had developed favipiravir 200 mg tablet formulation (FAVIR®). A randomized, two-treatment, two-period, two-sequence, single-dose, crossover study was designed to determine the bioequivalence of two favipiravir 200 mg tablet formulations, FAVIR® and AVIGAN® under fasting conditions. The plasma-concentration time profiles were used to characterize the rate and extent of absorption of favipiravir in the test and reference products. The pharmacokinetics parameters were calculated using non-compartmental model. The analysis of variance did not show any significant difference between the two formulations. The 90% confidence intervals of geometric least squares mean ratio (test/reference) for log transformed parameters were within 80.00%-125.00% of bioequivalence criteria: 98.33%-108.31% for AUC0-tlast, 97.72%-106.89% for AUC0-∞ and 91.43%-112.32% for Cmax. Both products were well tolerated and no serious adverse events were reported. This study demonstrated bioequivalence between FAVIR® and AVIGAN® and supported interchangeable use between these products.