Schubert Birthe, Pavlic Marion, Libiseller Kathrin, Oberacher Herbert
Institute of Legal Medicine, Innsbruck Medical University, Muellerstrasse 44, 6020, Innsbruck, Austria.
Anal Bioanal Chem. 2008 Dec;392(7-8):1299-308. doi: 10.1007/s00216-008-2447-4. Epub 2008 Oct 24.
The metabolic transformation pathways of the 1,4-benzodiazepine tetrazepam (C(16)H(17)ClN(2)O, average mass: 288.772) were studied with capillary LC-QqTOF-MS and -MS/MS by analyzing human plasma and urine samples collected from healthy volunteers. Each volunteer took 50 mg of tetrazepam, given in the form of one tablet of Myolastan (Sanofi-Synthelabo, Vienna, Austria). Accurate molecular mass measurements in full-scan mode (scan range: 50-700) were used to survey the collected samples for putative metabolic transformation products. Full-scan fragment ion mass spectra were collected in subsequent LC/MS/MS experiments. Each spectrum was matched to a spectral library containing 3759 MS/MS-spectra of 402 compounds, including eighteen different benzodiazepines, to prove the structural relatedness of a tentative metabolite to tetrazepam. This "similarity search" approach provided a rapid and powerful tool to exclude non-drug-related species, even without any knowledge of the fragmentation chemistry. Interpretation of tandem mass spectrometric data was only required in order to elucidate the site of transformation. Using this strategy, 11 major classes of tetrazepam metabolites were identified. Possible metabolic routes from tetrazepam to diazepam (C(16)H(13)ClN(2)O, average mass: 284.740) via repeated hydroxylation and dehydration of the cylohexenyl moiety were discovered. No evidence for extensive hydroxylation of tetrazepam at position 3 of the diazepine ring was found. In contrast to what is commonly believed, this distinct transformation reaction may be of only minor importance. Furthermore, the occurrence of demethylation, hydration, and glucuronidation reactions was proven.
采用毛细管液相色谱-四极杆飞行时间质谱联用仪（LC-QqTOF-MS）和串联质谱（MS/MS），通过分析从健康志愿者收集的人血浆和尿液样本，研究了1,4-苯二氮䓬类药物替马西泮（C(16)H(17)ClN(2)O，平均分子量：288.772）的代谢转化途径。每位志愿者服用50毫克替马西泮，以一片Myolastan（赛诺菲-圣德拉堡，奥地利维也纳）的形式给药。在全扫描模式（扫描范围：50-700）下进行精确分子量测量，以检测收集的样本中可能的代谢转化产物。在随后的液相色谱/串联质谱实验中收集全扫描碎片离子质谱。每个质谱图与一个包含402种化合物的3759个串联质谱图的谱库进行匹配，其中包括18种不同的苯二氮䓬类药物，以证明暂定代谢物与替马西泮的结构相关性。这种“相似性搜索”方法提供了一种快速而强大的工具，即使在不了解裂解化学的情况下，也能排除与药物无关的物质。只有为了阐明转化位点才需要对串联质谱数据进行解释。采用这种策略，鉴定出了11大类替马西泮代谢物。发现了替马西泮通过环己烯基部分的重复羟基化和脱水生成地西泮（C(16)H(13)ClN(2)O，平均分子量：284.740）的可能代谢途径。未发现替马西泮在二氮䓬环3位发生广泛羟基化的证据。与通常的看法相反，这种独特的转化反应可能只具有次要意义。此外，还证实了去甲基化、水合和葡萄糖醛酸化反应的发生。
