Interaction of Ketoconazole with Bovine Serum Albumin: Electrochemical, Spectroscopic and Molecular Modeling Studies

Abstract

The interaction of ketoconazole (KTZ) with bovine serum albumin (BSA) has been investigated by cyclic voltammetry, differential pulse voltammetry, UV-Vis absorption and fluorescence spectroscopy, viscosity measurements as well as molecular modeling methods. The measurements were performed in 0.1 mol L -1 phosphat buffer solution at pH = 7.4. Shifts in the peak potentials in cyclic Voltammetry, spectral changes in UV absorption and fluorescence titration, an increase in viscosity of BSA and the molecular modeling methods strongly support the electrostatic interaction between KTZ and BSA. The thermodynamic parameters H, G and S at different temperatures were calculated, showing that the electrostatic interactions and hydrophobic interaction are the main forces for the binding of KTZ to BSA. The binding constant (Kb) determined by UV absorption and fluorescence measurements are very close to the value determined by cyclic Voltammetry assuming that the binding equilibrium is static. Moreover, from molecular modeling method, a docked structure with minimum energy was obtained in which KTZ was located in minor grooves of BSA.