Thermodynamics of the solubility of reserpine in {{2-(2-ethoxyethoxy)ethanol + water}} mixed solvent systems at different temperatures

Thermodynamics of solubility of the bioactive compound reserpine in various {2-(2-ethoxyethoxy)ethanol + water} mixed solvent systems was investigated in this study. The solubility of reserpine was determined from T = (298.15 to 338.15) K at atmospheric pressure using the reported method of Higuchi and Connors. Values of the measured solubility of reserpine were correlated with the ideal and Yalkowsky models. The root mean square deviations (RMSD) were observed to be less than 0.020 by an ideal model. However, the RMSD values were observed as less than 0.050 by the Yalkowsky model. The mole fraction solubility of reserpine was observed highest in pure 2-(2-ethoxyethoxy)ethanol (7.69 · 10−4 at T = 298.15 K) and lowest in pure water (9.71 · 10−7 at T = 298.15 K) at each temperature investigated. The results of the Van't Hoff and Krug analysis (thermodynamic studies) indicated endothermic and spontaneous dissolution of reserpine in all {2-(2-ethoxyethoxy)ethanol + water} mixed solvent systems.