Adsorption of drugs on B₁₂N₁₂ and Al₁₂N₁₂ nanocages

The adsorption behavior of twelve drug molecules (5-fluorouracil, nitrosourea, pyrazinamide, sulfanilamide, ethionamide, 6-thioguanine, ciclopirox, 6-mercaptopurine, isoniazid, metformin, 4-aminopyridine, and cathinone) on B₁₂N₁₂ and Al₁₂N₁₂ nanocages was studied using density functional theory. In general, the drug molecules prefer to bind with the boron atom of the B₁₂N₁₂ nanocage and the aluminium atoms of the Al₁₂N₁₂ nanocage. However, a hydrogen atom is transferred from each of 5-fluorouracil, nitrosourea, 6-thioguanine, ciclopirox, and 6-mercaptopurine to the nitrogen atom of the Al₁₂N₁₂ nanocage. All the drug molecules are found to be chemisorbed on the B₁₂N₁₂ and Al₁₂N₁₂ nanocages. The adsorption energies of the drug/B₁₂N₁₂ system are linearly correlated with the molecular electrostatic potential minimum values of the drug molecules. The transfer of the hydrogen atom from the drug molecules to the nitrogen atom of the Al₁₂N₁₂ nanocage leads to relatively high adsorption energies. We observed significant changes in the reactivity parameters (e.g. electronic chemical potential) of the nanocages due to the chemisorption process. Overall, the QTAIM analysis indicates that the interactions between drug molecules and nanocages have a partial covalent character. Among the studied systems, the adsorption process was more spontaneous for the ciclopirox/Al₁₂N₁₂ system in water.