Estimation of the indomethacin solubility in ethanol + water mixtures by the extended Hildebrand solubility approach

Abstract

Indomethacin (IMC) is an analgesic 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 ethanol + water mixtures at 298.15 K. An acceptable correlative capacity of EHSA was found using a regular polynomial model in order four (overall deviation lower than 4.1%), when the W interaction parameter is related to the solubility parameter of the mixtures. Besides, the deviations obtained in the estimated solubility with respect to experimental solubility were lower compared with those obtained directly by means of an empiric regression of the experimental solubility as a function of the mixtures´ solubility parameters.