Extended hildebrand solubility approach in the estimation of indomethacin solubility in ethyl acetate + ethanol mixtures

Indomethacin (IMC) is a widely used as a non-steroidal anti-inflammatory drug, whose physicochemical properties have not been thoroughly studied. In this work the Extended Hildebrand Solubility Approach (EHSA) was applied to evaluate the solubility of IMC in ethyl acetate + ethanol mixtures at 298.15 K. A good predictive capacity of EHSA was found using regular polynomial models in order five, when the W interaction parameter is related to the solubility parameter of the mixtures. Nevertheless, the deviations obtained in the estimated solubility with respect to experimental solubility were of the same order when compared with those obtained directly by means of an empiric regression of the experimental solubility as a function of the mixtures solubility parameters.