OBJECTIVE: The global pandemic called COVID-19 has dragged the world into a 
healthcare crisis, and favipiravir is one of the most prescribed agents against 
the virus so far. Favipiravir is a repurposed antiviral agent in treatment of 
SARS-CoV-2 infection, and to meet the current need, pharmaceutical companies are 
working for manufacturing licensed generic favipiravir. For getting the 
marketing authorization, the bioequivalence of the generic product must be 
proven first. The aim of this study is to demonstrate the bioequivalence of a 
new favipiravir tablet formulation as compared to the reference tablet 
formulation in healthy male subjects under fasting conditions.
MATERIALS AND METHODS: To prove the bioequivalence, a randomized, single oral 
dose, cross-over, two-period study was carried out in 30 healthy subjects under 
fasting conditions. Plasma favipiravir levels were quantified by using an 
in-house-developed high performance liquid chromatography with mass spectrometry 
detector (LC-MSD) method.
RESULTS: The 90% CIs for the test/reference geometric mean ratios of the Cmax 
and AUC0-tlast were 88.02 - 103.11% and 98.19 - 102.06%, respectively.
CONCLUSION: This single-dose study has shown that the test and reference 
favipiravir products met the required bioequivalence criteria. Besides, both 
products were well tolerated and safe.