Solubility and thermodynamic parameters of a novel anti-cancer drug (DHP-5) in polyethylene glycol 400 + water mixtures

Solubility of dihydropyrimidine derivative 4-(4-ethoxyphenyl)-5-(3,4,5 trimethoxybenzoyl)-3,4-dihydropyrimidine-2(1H) one (DHP-5), a novel anticancer drug, was experimentally measured in PEG-400 + water binary solvent mixtures over a temperatures range from 298.15 to 318.15 K. Thermodynamic parameters including enthalpy, entropy and Gibbs free energy of the solubility data were calculated using van't Hoff equation. Experimental solubility data was employed to evaluate the relative performance of a number of models including van't Hoff, Apelblat, Yalkowsky and Jouyban–Acree models for their prediction efficacy. The Jouyban–Acree model covering both solvent composition and temperature effects on drug's solubility proved to be superior to the other three models for its prediction accuracy.