NEDA MOZAYYENI, ALI MORSALI, MOHAMMAD R. BOZORGMEHR, S. ALI BEYRAMABADI QUANTUM CHEMICAL INSIGHT INTO THE ADSORPTION MECHANISMS OF TROXACITABINE ONTO FUNCTIONALIZED CARBON NANOTUBES Using density functional theory, noncovalent interactions and possible mechanisms of covalent functionalization of drug troxacitabine with COOH and COCl functionalized carbon nanotube (NTCOOH and NTCOCl) have been investigated. It was specified that binding of drug troxacitabine with NTCOOH has more binding energy than NTCOCl and can act as a favorable system for troxacitabine drug delivery within biological and chemical systems (noncovalent). NTCOOH and NTCOCl can bond to the amino and hydroxyl groups of troxacitabine through OH (COOH mechanism) and Cl (COCl mechanism ) groups, respectively. The activation parameters related to COOH mechanism are higher than those related to COCl mechanism and therefore COCl mechanism is suitable for covalent functionalization. These results could be generalized to other similar drugs.