A DFT and molecular dynamics simulation study of single-walled carbon nanotube as a drug delivery system for few model nitrogen mustard drugs

Abstract

• Optimized geometries of the model nitrogen mustards substituted with heterocycles, SWCNT and the complexes between them were calculated using DFT technique. • Interaction energies were calculated from the optimized structures. • HOMO, LUMO, DOS, NBO and various quantum chemical descriptors were calculated for the optimized complexes. • NCI plots were calculated to show the interactions between drug and SWCNT • Molecular dynamics simulations were performed to investigate the effect of EtOH solvents on the stability of the complexes between drug and SWCNT Current study mainly describes the delivery of three model nitrogen mustard drugs with heterocyclic substituents by single-walled carbon nanotube (SWCNT) as a drug delivery system. The electronic properties and interaction energies were calculated using density functional theory (DFT). Results suggest that the model drugs bind exothermically with SWCNT. HOMO-LUMO, DOS plots and non-covalent interaction (NCI) plots indicate that the interaction between the drugs and SWCNT are weak. Further, calculations of quantum mechanical descriptors suggest that electron migration takes place from SWCNT to the drug. Finally, molecular dynamics simulation was performed to investigate the effect of EtOH co-solvent on the stability of the drug-SWCNT complex. The results suggest that the complexes are most stable in a water environment and the addition of EtOH co-solvent makes it unstable. In summary, all the results suggest that SWCNT may successfully deliver the investigated model nitrogen mustard drugs and these systems are most stable in a water solvent.