Research of sulfadiazine using subcritical water and water plus alcohol mixtures as the solvent: Solubility and thermodynamic property

Sulfonamides are drugs extensively used for the treatment of infections caused by gram-positive and gram negative microorganisms, some fungi, and certain protozoa. They are also used in agriculture to prevent and treat diseases in livestock. Sulfadiazine is a member of the sulfonamide family. In this study, the solubility of sulfadiazine in pure subcritical water and water + alcohol mixtures has been measured using a homemade system at (298 to 403) K under a constant pressure of 5.1 MPa. Our results revealed that the solubility of sulfadiazine was enhanced with increasing temperature and higher percentage of ethanol or propanol in water. Modified Apelblat equation and CNIBS/R-K model were used to correlate and predict the solubility of sulfadiazine in pure subcritical water as well as in subcritical water + alcohol mixtures. The predicted solubility values are in good correlation with the experimental data. In addition, "Apparent thermodynamic analysis" was applied to calculate the dissolution enthalpy property of the solution process. (C) 2018 Elsevier B.V. All rights reserved.