Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

The solubility of pioglitazone hydrochloride (Form I) was measured by the synthetic method in methanol-ethanol, methanol-1-propanol, methanol-acetone mixtures at temperatures ranging from283.15 K to 323.15 K. The solubility of pioglitazone hydrochloride (Form I) increased with increasing tem-perature. At a given temperature, solubility in different mixtures follows different rules. The experimental data were effectively correlated by the (CNIBS)/ Redlich-Kister model and the modified Apelblat model.The thermodynamic functions (enthalpy, entropy, and molar Gibbs free energy) of solution, mixing andthe activity coefficient were then calculated in different solvent mixtures. The dominant mechanismsof the solvent action for pioglitazone hydrochloride (Form I) in different mixtures were analyzed andexplained by enthalpy-entropy compensation. The solubility behavior for different mixtures may becontrolled by a different mechanism.