Enhancement of curcumin solubility by some choline chloride-based deep eutectic solvents at different temperatures

Abstract

Curcumin (CUR) is a biologically active substance and a natural antioxidant, but it is almost insoluble in water and has low bioavailability. A possible solution to this barrier could be to use solvents that exhibit low toxicity and are biodegradable. Choline chloride-based deep eutectic solvents (DESs) can be used as a co-solvent to increase the solubility of curcumin. The objectives of this study are to introduce and prepare DESs, to measure the solubility of CUR in water and DESs as well as in water-DES mixtures with different weight fractions. In this perspective, the solubility of CUR is measured in the mixtures of water with some DESs based on choline chloride (ChCl) and in pure solvents at T = 298.15 K to 318.15 K. The measured solubility data were correlated by the activity coefficients models e-NRTL and UNIQUAC. Finally, the apparent thermodynamic functions entropy, enthalpy, and Gibbs free energy were estimated for dissolution process using van't Hoff equation.