Solid–liquid equilibrium of sulbactam in pure solvents and binary solvent mixtures

• The solubility data of sulbactam in pure solvents and binary solvent mixtures were determined.
• The experimental solubility data in pure solvents were correlated by three models.
• The experimental solubility data in binary solvent mixtures were correlated by two models.
• The dissolution thermodynamic properties of sulbactam were obtained.

The solubility data of sulbactam in seven pure solvents and a binary solvent system were determined from 278.15 K to 308.15 K using a gravimetrical method under atmospheric pressure. Since sulbactam will decompose before melting, the group contribution method was used to estimate the melting point and the enthalpy of fusion of sulbactam. The measured data in pure solvents were correlated with the modified Apelblat equation, the Wilson model and the NRTL model. And for the binary solvent system, the CNIBS/R-K model and Jouyban–Acree model were used to correlate the solubility data. Moreover, the van’t Hoff equation was adopted to calculate the enthalpy, entropy and Gibbs energy change during the dissolution process.

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