Thermodynamic equilibrium and cosolvency of florfenicol in binary solvent system

The solubility of florfenicol in binary solvent mixtures of acetone + (methanol or ethanol or isopropanol) was experimentally measured at temperature ranging from 278.15 K to 318.15 K under atmospheric pressure (p = 0.1 MPa) by using the gravimetric method. In all the tested solvent systems, the solubility of florfenicol increases monotonically with increasing temperature at fixed solvent composition. While, as regards solvent composition, it shows a cosolvency phenomenon where the solubility has a maximum at a certain solvent compostion. The cosolvency was interpreted via mathematical model correlation using modified Apelblat equation, NRTL model, combined nearly ideal binary solvent/ Redlich-Kister (CNIBS/R-K) model, and Jouban-Acree model. Moreover, thermodynamic properties of the investigated systems including entropy, enthalpy and Gibbs free energy of the solubility data were calculated using NRTL model. The solubility results may be helpful to developing a proper crystallization process of yielding florfenicol nanoparticles.