Thermodynamics Study on the Theophylline-Nicotinamide Cocrystal

摘要

In this paper, the theophylline(TP)-nicotinamide(NCT) cocrystal was chosenas an example for studying the preparation analysis-identification and thermodynamic analysis of cocrystal systems. TP-NCT cocrystal was prepared by the methods of grinding, gringding, slurry and evaporation crystallization respectively. The dependence of the cocrystal solubility on the concentration of cocrystal components in solution were measured and correlated by cocrystal solubility product. The results indicate that TP and NCT do not ionize or form complexes in ethanol, and with the temperature increasing, both the solubility of the TP-NCT cocrystal and the solubility product increase. Finally, the ternary phasediagrams for the system of TP-NCT-ethanol at (298.15 and 308.15) K, which can provide the theoretical basis for crystallization processes, are presented.