Theoretical study of the interaction of the Favipiravir with B40 fullerene in aqueous solution for drug delivery

In this study, the interaction of the Favipiravir drug with B40 fullerene in aqueous solution was investigated with the Density Functional Theory (DFT). At first, the solvation Gibbs Free energy of fullerene and different isomers of the favipiravir drug and B40 fullerene were calculated. Results indicate that the solvation of B40 fullerene and the Favipiravir drug in water as a solvent are thermodynamically feasible. The percentage of different isomers of favipiravir was calculated from relative Gibbs energy and also, the most stable structure of favipiravir isomers was determined. Furthermore, the interaction of the most stable isomer of the Favipiravir in aqueous solution with B40 fullerene was investigated in different orientations. The results show that the Favipiravir drug strong interacts with B40 fullerene through the oxygen atom of the amide group with -31.53 kcal/mol and through the nitrogen atom of the pyrazine ring with -46.08 kcal/mol. Results of NBO analysis indicates that charges transfer occurred from drug to fullerene.