A Theoretical study of the effects of different solvents on the connections of methotrexate anticancer drug to carbon nanotubes carriers: AQM.MM study

In this investigation, the interaction of methotrexate anticancer drug (MTX) with single-wall carbon nanotubes (SWNTs) and double-wall carbon nanotubes (DWNTs) was examined via AMBER, OPLS, CHARMM and MM+ force fields through the molecular mechanic (MM) method. The calculations were performed out by the Monte Carlo simulation method at different temperatures. Using the mentioned force fields, we investigated the effects of gas-phase and various solvent media with different dielectric constants, i.e., water, DMSO, methanol, ethanol and DMF at ten different temperatures on the interaction of MTX with DWNTs. The interaction of MTX, with SWNTs and DWNTs in the gas phase has been processed using the DFT calculations. Thus, by utilizing a DFT method, we studied the effects of different solvents on the interaction of MTX, with carbon nanoparticles within the Onsager self-consistent reaction field (SCRF) model, as well as the effects of temperature on the stability of the interaction between compounds in various solvents. Frontier molecular orbitals (FMOs), total density of states (DOS), thermodynamic parameters and molecular electrostatic potentials (MEP) of the title compounds were investigated by theoretical calculations. Molecular properties such as the ionization potential (I), electron affinity (A), chemical hardness (η), electronic chemical potential (μ) and electrophilicity (ω) were investigated for the structures. The major finding is that the Monte Carlo and Molecular mechanics-quantum mechanics results for thermodynamic properties and conformer populations are in accord.