Pharmaceutical Co-Crystals of Pyrazinecarboxamide (PZA) with Various Carboxylic Acids: Crystallography, Hirshfeld Surfaces, and Dissolution Study
作者：Yang-Hui Luo and Bai-Wang Sun*
關鍵字：pharmaceutica co-crystals, DSC, Hirshfeld surface
論文來源：期刊
發表時間：2013年
Three new pharmaceutical co-crystals: 1 PZA-MA (malonic acid), 2 PZA-SA (succinic acid, a new polymorph of a reported one), and 3 PZA-GA (glutaric acid) have been prepared and characterized by di?erential scanning calorimetry (DSC), thermogravimetric analyses (TGA), and single-crystal X-ray di?raction. Wherein, PZA formed 1:1 co-crystals with MA and GA by acid?amide and acid?py heterosynthon, while it formed 2:1 co-crystal with SA by amide?amide homosynthon in addition to acid?amide and acid?py heterosynthon. Their melting points follow the order,
PZA-GA < PZA-MA < PZA-SA, which are lower than the melting points of the individual components. Hirshfeld surface analysis revealed that N?H···O hydrogen bonding and π···π interactions for PZA in them follow the order: PZA-MA > PZA-SA > PZA-GA, while H?H and O?O interactions follow the order: PZA-MA < PZA-SA < PZA GA. We also compared the Hirshfeld surfaces of the present co-crystals with the nine reported PZA co-crystals, which obtained important results. The studies of the solubility and dissolution showed a semiempirical inverse relationship with the melting point: the solubility follows the order, PZA-SA < PZA-GA < PZA-MA and dissolution rate follows the order, PZA-SA < PZA-MA < PZA-GA.