Assessment of the adsorption mechanism of amantadine drug onto pristine, Si- and Ge-doped Al₁₂N₁₂, and Al₁₂P₁₂ nanocages: A comparative DFT study

In the current study, the adsorption characteristics of pristine and doped (Si and Ge)- Al₁₂N₁₂ (AlN) and Al₁₂P₁₂ (AlP) nanocages towards the amantadine (AM) drug have been investigated in the gas phase by employing density functional theory (DFT). The study outcomes indicated that the amantadine drug interacts with the hexagonal ring of AlN and AlP nanocages through its H atoms and –NH₂ group. The values of the adsorption energies on the pristine nanocages vary from −2.31 to −31.55 kcal/mol in the vacuum environment. However, after swapping out one of the central Al atoms with a Si or Ge atom, the adsorption energy of the doped AlN and AlP significantly increases towards the AM drug. From a thermodynamic perspective, the adsorption process of AM drug over Al₁₂N₁₂ and Al₁₂P₁₂ nanocarriers had a spontaneous and exothermic nature. The crucial and essential characteristics of the atoms in molecule (AIM) analysis, the negative and positive amounts of the total electron energy density and Laplacian parameters, respectively, illustrate that the examination interactions are a partial covalent nature. Charge transfer occurs from the AM molecule to the AlN and AlP nanocages, according to the Natural Bond Orbital (NBO) analysis. Taken altogether, these findings propose that the doped AlN and AlP nanocarriers are efficient aspirants for the development of the AM drug delivery process.