Smart drug delivery: a DFT study of C24 fullerene and doped analogs for pyrazinamide.

The potential applicability of the C₂₄ nanocage and its boron nitride-doped analogs (C₁₈B₃N₃ and C₁₂B₆N₆) as pyrazinamide (PA) carriers was investigated using density functional theory. Geometry optimization and energy calculations were performed using the B3LYP functional and 6-31G(d) basis set. Besides, dispersion-corrected interaction energies were calculated at CAM (Coulomb attenuated method)-B3LYP/6-31G(d,p) and M06-2X/6-31G(d,p) levels of theory. The adsorption energy (E _ads), enthalpy (ΔH), and Gibbs free energy (ΔG) values for C₂₄-PA, C₁₈B₃N₃-PA, and C₁₂B₆N₆-PA structures were calculated. The molecular descriptors such as electrophilicity (ω), chemical potential (μ), chemical hardness (η) and chemical softness (S) of compounds were investigated. Natural bond orbital (NBO) analysis confirms the charge transfer from the drug molecule to nanocarriers upon adsorption. Based on the quantum theory of atoms in molecules (QTAIM), the nature of interactions in the complexes was determined. These findings suggest that C₂₄ and its doped analogs are promising candidates for smart drug delivery systems and PA sensing applications, offering significant potential for advancements in targeted tuberculosis treatment.