Solubility Measurement and Mathematical Modeling for Bosentan in Mixtures of Ethylene Glycol and Water at 293.15-313.15 K

The molar solubility of bosentan (BST) in mixtures of ethylene glycol (EG) + water at different temperatures from 293.15 to 313.15 K was measured by using the shake flask technique. Experimental solubility increased with increasing temperature and mass fraction of cosolvent; so that, the largest solubility was found in neat cosolvent at 313.15 K. The cosolvency models of Jouyban-Acree and its combined version with van't Hoff equation (Jouyban-Acree-van't Hoff model) were used for correlation of BST solubility data with the low values of mean relative deviations (MRD% <= 8.1). Furthermore, some untested data were predicted based on the achieved trained models at 298.15 K. X-ray powder diffraction was also served to analyze the equilibrium solid phase crystal of BST and the results turns out that no polymorphic transformation, solvate formation or crystal transition during the whole solvent crystallization process.