Spectroscopic Studies on the Interaction Between Novel Antiviral Drug Favipiravir and Serum Albumins

Under physiological conditions, in vitro interaction between favipiravir (FAV) and serum albumins (BSA/HSA) was investigated at excitation wavelength 280 nm and at different temperatures (298 K, 313 K) by fluorescence emission spectroscopy. The hydrogen bond, van der Waals forces and electrostatic interaction plays a major role in stabilizing the complex; the binding constants KA at different temperatures were calculated. The distance r between donor (BSA/HSA) and acceptor (FAV) was obtained according to fluorescence resonance energy transfer (1.55/1.90 nm for BSA/HSA-FAV systems). The effect of FAV on the conformation of BSA/HSA was analyzed using synchronous fluorescence spectroscopy and UV/vis absorption spectroscopy.