Kinetic and thermodynamic characteristics of crystallization of vancomycin

We investigated the effect of the major process parameters (crystallization temperature and time) on the efficiency of the vancomycin crystallization process and conducted a kinetic and thermodynamic analysis. The most clear and uniform vancomycin crystals with the highest yield (similar to 98%) were obtained at the optimum crystallization temperature (283 K) and time (1,440 min). The electron microscope, SEM, and XRD analyses showed that intact crystalline vancomycin was obtained when using a crystallization temperature of 283, 288, and 293 K. The kinetic analysis results revealed that the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was suitable with a high value for r(2) (> 0.9561) and low value for RMSD (< 0.0170). Finally, from the thermodynamic analysis the Gibb's free energy change (Delta G(0)), entropy change (Delta S-0), and enthalpy change (Delta H-0) were all negative, indicating that the crystallization process was spontaneous, irreversible, and exothermic.