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.

磺酰胺是广泛用于治疗由革兰氏阳性和革兰氏阴性微生物，某些真菌和某些原生动物引起的感染的药物。它们还用于农业中，以预防和治疗牲畜疾病。磺胺嘧啶是磺酰胺家族的成员。在这项研究中，磺胺嘧啶在纯亚临界水和水+醇混合物中的溶解度已使用自制系统在（298至403）K，5.1 MPa的恒定压力下进行了测量。我们的结果表明，磺胺嘧啶的溶解度随着温度的升高和水中乙醇或丙醇百分比的增加而增加。修改后的Apelblat方程和CNIBS / RK模型用于关联和预测磺胺嘧啶在纯亚临界水中以及在亚临界水+醇混合物中的溶解度。预测的溶解度值与实验数据具有良好的相关性。另外，应用“表观热力学分析”来计算固溶过程的溶解焓性质。