Thermodynamic of Transfer and Preferential Solvation of Antibiotic Cephradine in 1,4-Dioxane-Water Mixtures

Abstract

The ionization constants of cephradine in 0, 10, 20, 30, 40, 50, 60, 70, 80 and 90% ( v/v ) 1,4-dioxane-water mixed solvents were determined using a potentiometric technique and an automatic titrator. The measurements were performed at four different temperatures and 0.1 M KCl, and thus the thermodynamic parameters of ionization and transfer were evaluated. The ionization of cephradine has been found to be endothermic and entropically unfavourable. A non-linear dependence of the ionization Gibbs energies (Δ