Solubility and dissolution thermodynamics of sinapic acid in (DMSO plus water) binary solvent mixtures at different temperatures

Despite the various favorable characteristics of dimethyl sulfoxide (DMSO) in solubilization of hydrophilic as well as hydrophobic solutes, its cosolvency action for enhancing the solubility of poorly soluble drugs had rarely been investigated. Therefore, in this research work, the cosolvency action of DMSO was investigated in order to enhance the solubilization of bioactive nutraceutical sinapic acid (SA) in water. The solubilities (expressed as mole fraction) of SA in various (DMSO + water) binary solvent mixtures including neat solvents were determined at T = (298.15 to 318.15) K and p = 0.1 MPa. Experimental solubilities of SA were correlated well with Apelblat, Van't Hoff, Yalkowsky and Jouban-Acree models. The solubility (expressed as mole fraction) of SA was increasing with increasing in the temperature and the value of mass fraction of DMSO in (DMSO + water) mixtures. The highest mole fraction solubility of SA was observed in neat DMSO (1.58 x 10(-1) at T = 318.15 K). However, the lowest mole fraction solubility of SA was obtained in neat water (6.26 x 10(-5) at T = 298.15 K). Apparent thermodynamic analysis results indicated an endothermic and entropy-driven dissolution of SA in most of the (DMSO + water) mixtures investigated. Based on the results obtained in this work, SA was considered as freely soluble in neat DMSO and slightly soluble in neat water. (C) 2016 Elsevier B.V. All rights reserved.