Solubility and Dissolution Thermodynamics of Cefmetazole Acid in Four Neat Solvents and Preferential Solvation in Co-Solvent Mixtures of (Methanol, Ethanol or Isopropanol) + Water

Abstract

The solubilities of cefmetazole acid in methanol, ethanol, isopropanol and water were determined experimentally by using the saturation shake-flask method within the temperature range from (278.15 to 303.15) K under pressure p = 101.1 kPa. At a fixed temperature, the cefmetazole acid solubility falls in the order methanol > ethanol > isopropanol > water. The apparent dissolution enthalpy, dissolution entropy and Gibbs energy change were calculated. The acquired solubilities were correlated with Apelblat’s equation. The largest value of relative average deviation for mole fraction solubility was 0.45 × 10−2, and of root-mean-square deviation, 0.747 × 10−5. The type and extent and direction of solute–solvent interactions were identified using the concept of Linear Solvation Energy Relationship. In addition, the preferential solvation parameters (δx1,3) of cefmetazole acid in co-solvent mixtures of methanol (1) + water (2), ethanol (1) + water (2) and isopropanol (1) + water (2) were derived via the inverse Kirkwood–Buff integrals method. At 298.15 K, the magnitude of preferential solvation of cefmetazole acid by the co-solvent is highest in methanol mixtures, followed by ethanol mixtures, and finally by isopropanol mixtures.