Drugs delivery systems: Density functional theory study of 5-fluorouracil adsorption on hydrated silica carrier

G. BRIZUELA; A. JUAN; A. DIAZ COMPAÑY; S. SIMONETTI

Conferencia; 6th International IUPAC Conference On Green Chemistry; 2016

Silica-based mesoporous materials have been recently proposed as an efficient support for the controlled release of a popular anticancer drug, 5-fluorouracil (5-FU). Although the relevance of this topic, the atomistic details about the specific surface-drug interactions and the energy of adsorption are almost unknown. In this work, theoretical calculations using the Vienna Ab-initio Simulation Package (VASP) applying Grimme's ?D2 correction were performed to elucidate the drug-silica interactions and the host properties that control 5-FU drug adsorption on β-cristobalite (111) hydroxylated surface. This study shows that hydrogen bonding, electron exchange, and dispersion forces are mainly involved to perform the 5-FU adsorption onto silica. This phenomenon, revealed by favorable energies, results in optimum four adsorption geometries that can be adopted for 5-FU on the hydroxylated silica surface. Silanols are weakening in response to the molecule approach and establish H-bonds with polar groups of 5-FU drug. The final geometry of 5-FU adopted on hydroxylated silica surface is the results of Hbonding interactions which stabilize and fix the molecule to the surface and dispersion forces which approach it towards silica (111) plane. The level of hydroxylation of the SiO2(111) surface is reflected by the elevated number of hydrogen bonds that play a significant role in the adsorption mechanisms.