Solubility of sildenafil citrate in polyethylene glycol 400 + water mixtures at various temperatures

Abstract

The solubility of sildenafil citrate (SC) in binary aqueous mixtures of polyethylene glycol 400 (PEG 400) were determined at 293.2, 298.2, 303.2, 308.2 and 313.2 K. Density of the SC saturated solutions over the entire solvent composition and temperature range was measured by a pycnometer. The solubility and densities data were correlated by two models, which are the van't Hoff and Jouyban-Acree model. The apparent thermodynamic properties, dissolution enthalpy, dissolution entropy, and Gibbs free energy change of dissolution process of SC in all the mixed solvents were calculated according to van't Hoff and Gibbs equations. © 2017 Elsevier B.V.