Solubility Measurement and Correlation of Fosfomycin Sodium in Six Organic Solvents and Different Binary Solvents at Temperatures between 283.15 and 323.15 K

The solubility data of fosfomycin sodium (FOM-Na) in six pure solvents (methanol, ethanol, propanol, cyclohexane, acetone, N,N-dimethylformamide) and two binary solvents (methanol + ethanol, methanol + acetone) at temperatures ranging from 283.15 to 323.15 K were measured by a laser monitoring dynamic method at atmospheric pressure. It turned out that the solubility data decreased with increasing temperature, and also varies with the composition of the solvents. Moreover, the experimental data in pure solvents have been correlated with two thermodynamic models (i.e., modified Apelblat and van’t Hoff), and the data in binary solvents have been correlated with CNIBS/R-K equation and two modified versions of Jouyban–Acree models (Van’t-JA equation and Apel-JA equation), respectively. All the results showed a good agreement with the experimental data. Intermolecular interaction force and dielectric constants are introduced to explain the relationship between solubility and temperature. In addition, the analysis of the solubilities implies that higher temperature may destroy the forces between the solvent and solute molecules, leading to lower solubility. And this can give a guide to the design and optimization of the crystallization process of FOM-Na in the industry.