Density functional calculations on adsorption of 2-methylheptylisonicotinate antitubercular drug onto functionalized carbon nanotube

The interaction of 2-methylheptylisonicotinate (MHI) drug with (5,5) armchair single-wall carbon nanotube (SWNT) of finite length is studied using density functional theory. Carbon nanotubes can act as a suitable drug delivery vehicle for internalization of MHI within biological systems. DFT-PW91/DNP calculations reveal that the binding energies are negative for MHI-SWNT system and decreases with increase in functionalization, suggesting thermodynamic favorability for covalent attachment of functional moieties onto nanotube sidewall. Global reactivity descriptors determined from energies of frontier orbital help to understand the properties and reactivity of the drug-SWNT complex. Solvation studies indicate the enhanced solubility of MHI drug in presence of carbon nanotube support. These results are extremely relevant in order to identify the potential applications of functionalized carbon nanotubes as drug delivery systems. (C) 2011 Elsevier B.V. All rights reserved.