A systematic study on solubility and solvation of bioactive compound chrysin in some water plus cosolvent mixtures

The equilibrium solubility of flavonoid chrysin was evaluated using UV-Vis spectrophotometric method in various mixed solvents comprising 0-100% (v/v) dimethylformamide (DMF) and tetrahydrofuran (THF) in water and constant temperature (25.0 +/- 0.1) degrees C. From solubility data, the Gibbs free energy changes involved with the dissolution process of chrysin were also determined. The obtained results showed that the solubility of chrysin increases by increasing the DMF and THF proportion in solution. Furthermore, the preferential solvation parameters of the solute chrysin by co-solvents DMF and THF, delta X-cosolv,X-S, were derived using the inverse Kirkwood-Buff integrals (IKBI) approach. From the delta X-cosolv,X-S data, it was found that water is the preferred solvent in the solvation shell of chrysin in water-rich mixtures but the co-solvents DMF and THF are preferred in intermediate compositions to pure co-solvent The variation of this parameter in the binary mixtures studied is discussed based on types of intermolecular solute-solvent interactions and structural characteristics of flavonoid chrysin. (c) 2016 Elsevier B.V. All rights reserved.