Solubility of Carvedilol in Ethanol plus Propylene Glycol Mixtures at Various Temperatures

Abstract

Solubilities of carvedilol (CVD) in binary mixtures of (ethanol + propylene glycol (PG)) at 298.2, 303.2, 308.2, and 313.2 K are reported. The modified versions of the van't Hoff and Gibbs equations were used to calculate the thermodynamic properties (enthalpy (Delta H degrees)), entropy (Delta S degrees), and Gibbs energy (Delta G degrees) standard changes of solutions) for CVD dissolved in (ethanol (1) + PG (2)) mixtures from the solubility data. The solubility data of CVD in (ethanol (1) + PG (2)) at different temperatures were correlated using different mathematical models, i.e., the Jouyban-Acree model, a combination of the Jouyban-Acree model with the van't Hoff model, and two modified versions of the Jouyban-Acree model. Solubility data of seven drugs in (ethanol (1) + PG (2)) at different temperatures were used to develop a quantitative structure-property relationship model for predicting solubility in solvent mixtures. In addition, enthalpy-entropy compensation using Delta H degrees vs Delta G degrees and Delta H degrees vs T Delta S degrees which explains the mechanism of cosolvency at different temperatures was discussed.