5-fluorouracil adsorption on hydrated silica: density functional theory study

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

Conferencia; 12th International Conference on the Fundamentals of Adsorption; 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) were performed to elucidate the drug-silica interactions and the host properties that control 5-FU drug loading and release on the pore wall of SiO2(111) hydroxylated surface. This study shows that complexation, ionic exchange, and hydrogen bonding are mostly employed to perform the 5-FU adsorption onto hydrated silica. The high degree of hydroxylation is reflected by the elevated number of hydrogen bonds and this characteristic has a significant role in the adsorption mechanisms. The atomiccalculations suggest that the increased H-bonding interactions between the 5-FU drug and the hydrated silica carrier can cause a slower release rate that is advantageous for the anticancer drug delivery. The H-bonding interaction is not large enough to stop drug diffusion, but is sufficient to apply a substantial degree of controlled release. In addition, silica protects the drug from fast degradation and can improve drug concentration; therefore, lower dosages of medicine could be required.