Complexation of C60 Fullerene with Aromatic Drugs

The contributions of various physical factors to the energetics of complexation of aromatic drug molecules with C60 fullerene are investigated in terms of the calculated magnitudes of equilibrium complexation constants and the components of the net Gibbs free energy. Models of complexation are developed taking into account the polydisperse nature of fullerene solutions in terms of the continuous or discrete (fractal) aggregation of C60 molecules. Analysis of the energetics has shown that stabilization of the ligandfullerene complexes in aqueous solution is mainly determined by intermolecular van der Waals interactions and, to lesser extent, by hydrophobic interactions. The results provide a physicochemical basis for a potentially new biotechnological application of fullerenes as modulators of biological activity of aromatic drugs.