Reactions of 4-bis(2-chloroethyl)aminophenylacetic acid (phenylacetic acid mustard) in physiological solutions
作者:Toni Pettersson-Fernholm、Juhani Vilpo、Markus Kosonen、Kristo Hakala、Jari Hovinen
DOI:10.1039/a903013a
日期:——
4-Bis(2-chloroethyl)aminophenylacetic acid (phenylacetic acid mustard, 2) is the major metabolite of the cancer chemotherapeutic agent chlorambucil (1). Although its high antitumor activity and high toxicity to normal tissues have been known for a long time, no detailed chemical data on its reactions in aqueous media have been available. According to the present results 2 is decomposed in aqueous solutions by the same mechanism as other aromatic and aliphatic nitrogen mustards: an intramolecular, rate determining attack of the unprotonated nitrogen to form an aziridinium ion intermediate is followed by attack of an external nucleophile. Species 2 is considerably more stable in whole plasma than in plasma ultrafiltrate (t1/2 at 37 °C 10 h and 37 min, respectively). Also the product distribution is completely different: while in protein-depleted plasma the only reaction is hydrolysis, in plasma the predominant reactions are non-covalent and covalent binding of 2 to albumin. The present information is important when clinical evaluation of chlorambucil, or in vitro evaluation of phenylacetic acid mustard, is performed in order to determine efficacy and bioavailability of these compounds.
4-双(2-氯乙基)氨基苯乙酸(苯乙酸芥子气,2)是癌症化疗药物氯霉素(1)的主要代谢产物。虽然人们很早就知道它具有很强的抗肿瘤活性,而且对正常组织具有很强的毒性,但却没有关于它在水介质中反应的详细化学数据。根据目前的研究结果,2 在水溶液中的分解机理与其他芳香族和脂肪族氮芥相同:未质子化的氮受到分子内速率决定性的攻击,形成氮丙啶离子中间体,然后受到外部亲核剂的攻击。物种 2 在整个血浆中比在血浆超滤液中稳定得多(在 37 °C 下的 t1/2 分别为 10 小时和 37 分钟)。此外,产物的分布也完全不同:在蛋白质贫乏的血浆中,唯一的反应是水解,而在血浆中,主要的反应是 2 与白蛋白的非共价和共价结合。在对氯霉素进行临床评估或对苯乙酸芥子气进行体外评估以确定这些化合物的疗效和生物利用度时,本研究提供的信息非常重要。