The solubility of omeprazole sulfide in (ethanol + ethyl acetate) binary solvent mixtures was measured within the temperature range from 277.65 to 333.15 K. The experimental data were fitted using CNIBS/R-K equation and the Jouyban-Acree equation, respectively. All the two equations were proven to give good representations of the experimental values. Computational results showed that the CNIBS/R-K equation was superior to the other equation. The thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy and entropy, were calculated by the van't Hoff analysis. The values of both the enthalpy change and the standard molar Gibbs free energy change of solution were positive, which indicated that the process was endothermic. (C) 2015 Elsevier B.V. All rights reserved.