Theoretical Study of the interaction of Chlorambucil and Melphalan with carbon nanotube surface as a drug nanocarrier in aqueous solution

Biological application of carbon nanotubes in drug delivery is our main concern in this investigation. For this purpose, possibility of the interaction of chlorambucil and melphalan with carbon nanotube surface as a carrier was studied in both gas phase and in aqueous media. At first step each species was modeled using quantum mechanical calculations, in the next step, solvation free energies and association free energies of considered structures in water were studied by Monte Carlo simulation and perturbation method. The results of density functional calculations in gas phase showed that both two drugs can interact with carbon nanotube. Monte Carlo simulation results revealed that interaction with carbon nanotube enhanced the solubility of drugs in water which improve the pharmaceutical applications. Calculated association free energies indicated that melphalan produced more stable complex with carbon nanotube than chorambucil in aqueous solution. This tendency could be observed in gas and liquid phase similarly.