Solubility of tadalafil in aqueous mixtures of Transcutol® and PEG 400 revisited: correlation, thermodynamics and preferential solvation

Mole fraction solubilities of tadalafil (3) in aqueous mixtures Transcutol® and PEG 400 at temperatures from 298.15 to 333.15 K were analysed following Hildebrand solubility parameters. Cosolvency models for representing various also provided correlation/prediction purposes. Apparent thermodynamic quantities dissolution processes calculated based on van’t Hoff Gibbs equations. Non-linear enthalpy–entropy compensation was observed transfer more polar less solvent systems. Preferential solvation parameters 313.15 determined by means the inverse Kirkwood-Buff integrals (IKBI). Tadalafil is preferentially solvated water water-rich but 0.12 < x1 1.00. In former case, this result could be due hydrophobic hydration around non-polar moieties tadalafil. Otherwise, all mixtures.