Merck KGaA, Darmstadt, Germany (L.R., J.J., C.v.E., A.K., C.K., A.M., K.G., L.B.); Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany (L.R., A.K.H.H., R.W.H.); and Department of Pharmacy, Saarland University, Saarbrücken, Germany (L.R., A.K.H.H., R.W.H.)
Merck KGaA, Darmstadt, Germany (L.R., J.J., C.v.E., A.K., C.K., A.M., K.G., L.B.); Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany (L.R., A.K.H.H., R.W.H.); and Department of Pharmacy, Saarland University, Saarbrücken, Germany (L.R., A.K.H.H., R.W.H.).
Drug Metab Dispos. 2022 Apr;50(4):320-326. doi: 10.1124/dmd.121.000663. Epub 2022 Feb 3.
Praziquantel (PZQ) is the drug of choice for treatment of the neglected tropical disease schistosomiasis. Although the drug has been extensively used over several decades and its metabolism well studied (several oxidative metabolites are known from literature), the knowledge of the complete structure of some of its metabolites remains elusive. Conventional techniques, such as nuclear magnetic resonance or liquid chromatography mass spectrometry were used in the past to investigate phase I and phase II metabolites of PZQ. These techniques are either limited to provide the complete molecular structure (liquid chromatography mass spectrometry) or require large amount of sample material (NMR), which are not always available when systems are used for investigation of the metabolites. In this study, we describe new structures of -PZQ metabolites generated from human liver microsomes using the crystalline sponge method. After chromatographic separation and purification of the oxidative metabolites, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis was conducted to narrow down the position of oxidation to a certain part of the molecule. To determine the exact position of hydroxylation, singe-crystal X-ray diffraction analysis of the crystalline sponges and absorbed analyte was used to identify the structure of -PZQ and its metabolites. The crystalline sponge method allowed for complete structure elucidation of the known metabolites --4'-hydroxy-PZQ (M1), --4'-hydroxy-PZQ (M2) and -/-11b-hydroxy-PZQ (M6) as well as the unknown metabolites -9-hydroxy-PZQ (M3) and -7-hydroxy--PZQ (M4). For comparison of structural elucidation techniques, one metabolite (M3) was additionally analyzed using NMR. SIGNIFICANCE STATEMENT: The information content of the metabolic pathway of praziquantel is still limited. The crystalline sponge method allowed the complete structural elucidation of three known and two unknown metabolites of -praziquantel, using only trace amounts of analyte material, as demonstrated in this study.
吡喹酮（PZQ）是治疗被忽视的热带病血吸虫病的首选药物。尽管该药物已被广泛使用了几十年，其代谢产物也得到了很好的研究（文献中已知有几种氧化代谢产物），但一些代谢产物的完整结构仍难以捉摸。过去，人们曾使用核磁共振或液相色谱-质谱联用技术来研究 PZQ 的 I 相和 II 相代谢产物。这些技术要么仅限于提供完整的分子结构（液相色谱-质谱联用），要么需要大量的样品材料（核磁共振），而当系统用于代谢产物研究时，这些并不总是可用的。在本研究中，我们描述了使用结晶海绵法从人肝微粒体中生成的 -PZQ 代谢产物的新结构。在对氧化代谢产物进行色谱分离和纯化后，进行超高效液相色谱-四极杆飞行时间质谱分析，以将氧化位置缩小到分子的某个部分。为了确定羟基化的确切位置，使用结晶海绵和吸收分析物的单晶 X 射线衍射分析来鉴定 -PZQ 和其代谢产物的结构。结晶海绵法允许对已知代谢产物——4'-羟基-PZQ（M1）、4'-羟基-PZQ（M2）和 -/-11b-羟基-PZQ（M6）以及未知代谢产物 -9-羟基-PZQ（M3）和 -7-羟基-PZQ（M4）进行完整的结构阐明。为了比较结构阐明技术，本研究还使用 NMR 分析了一种代谢产物（M3）。意义：吡喹酮代谢途径的信息含量仍然有限。结晶海绵法仅使用痕量的分析物材料，就能够对 -吡喹酮的三种已知和两种未知代谢产物进行完整的结构阐明，如本研究所示。
