LAUSR

Abstract The solubility of caffeine in non-aqueous mixed solutions of carbitol and ethanol at different temperatures are determined by a shake-flask method and fitted to some reported cosolvency models including the van't Hoff, the double log-log, the mixture response surface, the Yalkowsky, the Jouyban-Acree, the Jouyban-Acree-van't Hoff, and the modified Wilson models. Along with solubility, the densities of caffeine saturated mixtures are also measured and correlated with the Jouyban-Acree model. In order to study the accuracy of the employed models, the mean relative deviations (MRD%) of the back-calculated solubility and density data are calculated. Furthermore, the apparent thermodynamic properties of caffeine dissolution process in the mixed solutions of carbitol and ethanol are also calculated by using van't Hoff and Gibbs equations.