College of Instrumentation & Electrical Engineering, Jilin University, Changchun, Jilin 130061, China.
College of Instrumentation & Electrical Engineering, Jilin University, Changchun, Jilin 130061, China; Institute of Automation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250014, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 5;228:117591. doi: 10.1016/j.saa.2019.117591. Epub 2019 Nov 15.
Pyrazinamide and isoniazid, as two first-line anti-tuberculosis drugs, are investigated by terahertz time-domain spectroscopy (THz-TDS). Both pyrazinamide and isoniazid have three absorption peaks, at 0.50, 0.71, 1.42 THz and 1.16, 1.46, 1.56 THz, respectively, which can be used as the basis for qualitative identification of these two drugs. In order to gain insight into the origin of the characteristic absorption peaks, density functional theory (DFT) based on single molecular, dimer, and crystalline structures of pyrazinamide and isoniazid are performed. The purpose of the calculation based on the single molecular structure is to understand the intramolecular interaction, while those based on the dimer and crystalline structures are to investigate the intermolecular interactions in PNZ and INZ. Comparing the theoretical results of the dimer and crystalline based structures reveals that the crystalline structure leads to vibrational spectra that are closer to the experimental values in terms of the number of absorption peaks and the positions of the absorption peaks. Vibrational mode assignments can be summarized as that the characteristic absorption peaks of pyrazinamide mainly come from intermolecular interaction, and the characteristic absorption peaks of isoniazid originate from both the intramolecular and intermolecular interactions. Our experimental and theoretical results indicate that the combination of THz-TDS with DFT is an effective approach for identification of molecules with pharmaceutical significance.
吡嗪酰胺和异烟肼作为两种一线抗结核药物，通过太赫兹时域光谱（THz-TDS）进行研究。吡嗪酰胺和异烟肼都有三个吸收峰，分别在 0.50、0.71、1.42 THz 和 1.16、1.46、1.56 THz，可作为这两种药物定性鉴别的依据。为了深入了解特征吸收峰的起源，基于吡嗪酰胺和异烟肼的单分子、二聚体和晶体结构进行了密度泛函理论（DFT）计算。基于单分子结构的计算旨在了解分子内相互作用，而基于二聚体和晶体结构的计算旨在研究 PNZ 和 INZ 中的分子间相互作用。比较二聚体和晶体结构的理论结果表明，晶体结构导致振动光谱在吸收峰的数量和位置上更接近实验值。振动模式的归属可以总结为：吡嗪酰胺的特征吸收峰主要来自分子间相互作用，而异烟肼的特征吸收峰既来自分子内相互作用，也来自分子间相互作用。我们的实验和理论结果表明，太赫兹时域光谱（THz-TDS）与密度泛函理论（DFT）的结合是识别具有药物意义的分子的有效方法。
