Ingavirin (6--5-oxohexanoic acid, Figure 1) was provided as a
pure substance by the manufacturer (Valenta Pharmaceuticals, Moscow, Russia). Tamiflu (oseltamivir
phosphate, LaRoche, Switzerland), 6-azacytidine (Institute of Molecular Biology and Genetics, Kiev,
Ukraine) and ribavirin (ICN Biochemicals, USA) were used in the experiments as reference drugs.
