The Prediction of Nanoscale Drug Molecular Structure and Acid Dissociation Constants of 5-Fluorouracil in Aqueous Solution Using DFT Methods

Abstract

Background and Objective : In this work, dissociation of nano drug 5-Fluorouracil derivatives was studied theoretically.
Methodology : For this purpose, Gibbs free energy values for neutral and deprotonated forms of 5-Fluorouracil were calculated at
gas and aqueous phases by using density functional theory (DFT) method. Solvent effects are taken into account by means of
polarizable continuum model (PCM). Result : It was shown that, theoretically calculated pKa values are in good agreement with
the existing experimental pKa values, which are determined from capillary electrophoresis, potentiometric titration and UV–visible
spectrophotometric measurements. Conclusion : In summary, cluster continuum method with implicit-explicit solvent molecules
was used for calculation of pKa values. Total energies and molecular parameters were obtained for 5-FUra nanoscale drug systems,
at B3LYP/6-31G(d) level of theory for the anion, cation, and neutral species.