Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.
J Pharm Biomed Anal. 2012 Dec;71:168-72. doi: 10.1016/j.jpba.2012.07.030. Epub 2012 Aug 3.
Although the chemical synthesis of wogonin (5,7-dihydroxy-8-methoxy-2-phenyl-4H-chromen-4-one) has been established, the impurity profile of this pharmaceutical agent is still not fully understood. In this study, a novel process related impurity present in the synthetic wogonin was isolated by preparative HPLC. Its structure elucidation was unambiguously carried out by NMR, HRMS and IR spectra, and it was characterized as 6-chloro-5,7-dihydroxy-8-methoxy-2-phenyl-4H-chromen-4-one (imp-1), a new compound which had never been reported before. Moreover, forced degradation studies were also carried out, and wogonin was shown to undergo isomerzation under basic stress condition to form a major degradant, 5,7-dihydroxy-6-methoxy-2-phenyl-4H-chromen-4-one (imp-2) using HPLC-Q-TOF-MS/MS technique. Finally, a selective and simple routine HPLC method was developed for simultaneous quantification of wogonin and the two related compounds. The proposed method is useful for purity control during the process development of wogonin and laboratory-prepared preparations. Their formation pathways were also discussed.
虽然已经建立了汉黄芩素（5,7-二羟基-8-甲氧基-2-苯基-4H-色烯-4-酮）的化学合成方法，但该药物制剂的杂质概况仍不完全清楚。在这项研究中，通过制备 HPLC 从合成汉黄芩素中分离出一种新型工艺相关杂质。通过 NMR、HRMS 和 IR 光谱明确地阐明了其结构，并将其鉴定为 6-氯-5,7-二羟基-8-甲氧基-2-苯基-4H-色烯-4-酮（imp-1），这是一种以前从未报道过的新化合物。此外，还进行了强制降解研究，结果表明汉黄芩素在碱性应激条件下会发生异构化，形成主要降解产物 5,7-二羟基-6-甲氧基-2-苯基-4H-色烯-4-酮（imp-2），使用 HPLC-Q-TOF-MS/MS 技术。最后，开发了一种用于同时定量测定汉黄芩素和两种相关化合物的选择性和简单常规 HPLC 方法。该方法可用于汉黄芩素的工艺开发和实验室制备过程中的纯度控制。还讨论了它们的形成途径。
