Characterization of Cocrystal Formation Structure of Nitrofurantoin and Urea Based on Terahertz and Raman Spectroscopy Combined with DFT Calculation

In this study, the vibrational modes of nitrofurantoin, urea, and cocrystal were characterized by terahertz time domain spectroscopy and Raman spectroscopy. The results indicate that both terahertz and Raman spectroscopy can effectively identify cocrystal and parent materials, with terahertz spectroscopy being more prominent. Meanwhile, the vibrational modes and structural optimization of four theoretical cocrystal configurations of the two drugs were simulated by density functional theory (DFT). Comparing the theoretical results with the experimental results shows that theoretical configuration D is most consistent with the experimental results. The results provide rich information on the pharmaceutical cocrystal to improve the physicochemical properties and pharmacological activities of specific pharmaceuticals at the molecular level. It shows that terahertz and Raman vibrational spectroscopy combined with DFT calculated is an effective method to analyze weak intermolecular interactions and characterize the molecules with cocrystal.