Pyrazinamide-3-Nitrophthalic Acid Cocrystals: Synthesis, Transformation, and Property Evaluation

The generation of multiple stoichiometric cocrystals from safe and nontoxic water is a rare occurrence. This study explored three different stoichiometric cocrystals (1:1, 1:2, and 2:1) of pyrazinamide-3-nitrophthalic acid cocrystals characterized by single crystal X-ray diffraction, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectrophotometry. Besides, the hydrogen bonding interaction was analyzed by the molecular electrostatic potential surfaces and the Hirshfeld surface. The hygroscopicity and solubility of the three cocrystals and the study of cocrystal transformation revealed a strong correlation between the properties of the cocrystals and the internal arrangement of the molecules. The most stable form (1:2) showed the strongest stability and the best performance in the evaluation test and had the greatest application potential.