Solubility and thermodynamic function of bergenin in different (DMSO plus water) mixtures at different temperatures

The cosolvency action of dimethyl sulfoxide (DMSO) in solubility enhancement and thermodynamic function of drugs had rarely been investigated in literature. Hence, in the current research work, the cosolvency action of DMSO was evaluated for the solubilization of bergenin. The mole fraction solubilities of bergenin in different binary solvent mixtures of DMSO and water were measured at five different temperatures i.e. T = (298.15 to 318.15) K and atmospheric pressure (p = 0.1 MPa). The resulting experimental data of bergenin were correlated well with three semiempirical mathematical models (Apelblat, van't Hoff and Yalkowsky models). The mole fraction solubility of bergenin was found to be increased with increase in the temperature and mass fraction of DMSO in binary solvent mixtures. The highest and lowest mole fraction solubility of bergenin was recorded in neat DMSO (2.29 x 10(-2) at T = 318.15 K) and neat water (7.50 x 10(-5) at T = 298.15 K), respectively. Thermodynamic treatment of solubility data of bergenin supported that its dissolution was an endothermic and entropy-driven in all (DMSO + water) binary solvent mixtures investigated. (C) 2016 Elsevier B.V. All rights reserved.