Experimental solubility of clotrimazole and some thermodynamic aspects of dissolution in different solvents

Abstract

Equilibrium solubility of clotrimazole, an important antimycotic drug, was measured between (293.15–313.15) K in four pharmaceutically relevant solvents including buffer pH 2.0, buffer pH 7.4, hexane and 1-octanol. The experimental solubility results were correlated by modified Apelblat and van’t Hoff equations. The compound melting temperature and enthalpy were determined. The activity coefficients at infinite dilution of clotrimazole in each solvent were calculated from experimental data on solubility and thermophysical properties. Substitution aqueous solvents for organic ones leads to lower activity coefficients and higher solubility of the drug. The limiting partial molar excess enthalpies, entropies and Gibbs energies of clotrimazole were evaluated.