Wang Jian, Zhou Jinjin, Xu Yu, Zhu Bingqi, Jin Yong
Zhejiang University of Technology, Hangzhou, 310014, China; Key Laboratory for Core Technology of Generic Drug Evaluation National Medical Product Administration, Zhejiang Institute for Food and Drug Control, Hangzhou, 310052, China.
Zhejiang University of Technology, Hangzhou, 310014, China.
J Pharm Biomed Anal. 2020 May 30;184:113196. doi: 10.1016/j.jpba.2020.113196. Epub 2020 Feb 20.
Two unknown impurities in roxithromycin were discovered and preliminarily characterized by two-dimensional liquid chromatography coupled with QTOF mass analyzer (2D LC-QTOF MS/MS). The column-switching technique of 2D LC made the chromatographic conditions in official standard of roxithromycin compatible with mass spectrometric detector. The complete MS/MS fragmentation patterns of the impurities were studied to obtain structural information of these impurities. Furthermore, these two impurities were separated and purified by preparative HPLC, and their structures were confirmed by 1D and 2D nuclear magnetic resonance (NMR). Structural elucidation of two impurities by H NMR, C NMR, the H-H COSY, HSQC and HMBC NMR spectra has been discussed. Based on high resolution MS/MS and NMR data, the structures of these two impurities were elucidated respectively as 11-O-[(2-Methoxyethoxy) methyl] roxithromycin and de(N-methyl)-N-formyl roxithromycin. In addition, the mechanisms for formation of the impurities were also proposed.
通过二维液相色谱联用QTOF质谱仪（2D LC-QTOF MS/MS）发现了罗红霉素中的两种未知杂质，并对其进行了初步表征。二维液相色谱的柱切换技术使罗红霉素官方标准中的色谱条件与质谱检测器兼容。研究了杂质的完整MS/MS碎裂模式，以获得这些杂质的结构信息。此外，通过制备型高效液相色谱对这两种杂质进行了分离和纯化，并通过一维和二维核磁共振（NMR）确定了它们的结构。讨论了通过氢核磁共振（H NMR）、碳核磁共振（C NMR）、氢-氢化学位移相关谱（H-H COSY）、异核单量子相干谱（HSQC）和异核多键相关谱（HMBC）核磁共振谱对两种杂质进行结构解析的过程。基于高分辨率MS/MS和NMR数据，分别确定这两种杂质的结构为11-O-[(2-甲氧基乙氧基)甲基]罗红霉素和去（N-甲基）-N-甲酰基罗红霉素。此外，还提出了杂质的形成机制。
