Calorimetric and spectroscopic studies of interactions of PPI G4 dendrimer with tegafur in aqueous solutions

Tegafur (TF) is a 5-fluorouracil (FU) derivative used in cancer therapy with the hydrogen atom substituted by a tetrahydrofuran ring. The results of solubility measurements, equilibrium dialysis, H-1 NMR titration and isothermal calorimetric titration (ITC) indicate that the surface of a PPI G4 macromolecule binds approximately 30 TF particles with the constant logK = 2.7 in an exothermic and thermodynamically spontaneous fashion in an aqueous environment at room temperature. The comparison of obtained parameters of TF binding by PPI G4 dendrimer with the literature data describing FU binding by PPI G4 dendrimer allowed to draw conclusions regarding the influence of hydrophobic tetrahydrofuran ring in the TF molecule on the stoichiometry, affinity and thermodynamics of the ligand binding by PPI G4 macromolecule in an aqueous medium. (C) 2021 Elsevier B.V. All rights reserved.