Solubility of naproxen in ethyl acetate + ethanol mixtures at several temperatures and correlation with the Jouyban–Acree model

By using the van’t Hoff and Gibbs equations the thermodynamic functions Gibbs energy, enthalpy, and entropy of solution and of mixing of naproxen (NAP) in some ethyl acetate + ethanol mixtures were evaluated from solubility data determined at several temperatures. By means of enthalpy–entropy compensation analysis, a non linear ΔsolnH° vs. ΔsolnG° compensation plot with negative and positive slopes was obtained if all the composition intervals are considered. Finally, the Jouyban–Acree model has been applied to correlate the drug solubilities as well as the respective thermodynamic quantities of solution in these solvent mixtures.

► Thermodynamic quantities of solution, mixing and solvation were obtained for naproxen. ► A non-linear plot of ΔsolnH° vs. ΔsolnG° compensation is found for naproxen at 303.0 K. ► Jouyban–Acree model in second degree was useful to correlate the naproxen solubility.