Bergh Marianne Skov-Skov, Bogen Inger Lise, Grafinger Katharina Elisabeth, Huestis Marilyn A, Øiestad Åse Marit Leere
Section for Drug Abuse Research, Department of Forensic Sciences, Division of Laboratory Medicine, Oslo University Hospital, Oslo, Norway.
Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, The Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.
Drug Test Anal. 2024 Dec;16(12):1544-1557. doi: 10.1002/dta.3668. Epub 2024 Mar 9.
N-Ethyl-N-propyltryptamine (EPT), 4-hydroxy-N-ethyl-N-propyltryptamine (4-OH-EPT), and 5-methoxy-N-ethyl-N-propyltryptamine (5-MeO-EPT) are new psychoactive substances classified as tryptamines, sold online. Many tryptamines metabolize rapidly, and identifying the appropriate metabolites to reveal intake is essential. While the metabolism of 4-OH-EPT and 5-MeO-EPT are not previously described, EPT is known to form metabolites by indole ring hydroxylation among others. Based on general knowledge of metabolic patterns, 5-MeO-EPT is also expected to form ring hydroxylated EPT (5-OH-EPT). In the present study, the aim was to characterize the major metabolites of EPT, 4-OH-EPT, and 5-MeO-EPT, to provide markers for substance identification in forensic casework. The tryptamines were incubated with pooled human liver microsomes at 37°C for up to 4 h. The generated metabolites were separated and detected by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis. The major in vitro EPT metabolites were formed by hydroxylation, N-dealkylation, and carbonylation. In comparison, 4-OH-EPT metabolism was dominated by double bond formation, N-dealkylation, hydroxylation, and carbonylation in vitro and hydroxylation or carbonylation combined with double bond loss, carbonylation, N-dealkylation, and hydroxylation in vivo. 5-MeO-EPT was metabolized by O-demethylation, hydroxylation, and N-dealkylation in vitro. The usefulness of the characterized metabolites in forensic casework was demonstrated by identification of unique metabolites for 4-OH-EPT in a human postmortem blood sample with suspected EPT or 4-OH-EPT intoxication.
N-乙基-N-丙基色胺（EPT）、4-羟基-N-乙基-N-丙基色胺（4-OH-EPT）和5-甲氧基-N-乙基-N-丙基色胺（5-MeO-EPT）是归类为色胺的新型精神活性物质，在网上售卖。许多色胺代谢迅速，识别合适的代谢物以揭示摄入情况至关重要。虽然此前未描述4-OH-EPT和5-MeO-EPT的代谢情况，但已知EPT会通过吲哚环羟基化等方式形成代谢物。基于代谢模式的一般知识，预计5-MeO-EPT也会形成环羟基化的EPT（5-OH-EPT）。在本研究中，目的是表征EPT、4-OH-EPT和5-MeO-EPT的主要代谢物，为法医案件工作中的物质鉴定提供标志物。将色胺与混合的人肝微粒体在37°C孵育长达4小时。通过超高效液相色谱-四极杆飞行时间质谱分析分离并检测生成的代谢物。体外EPT的主要代谢物通过羟基化、N-脱烷基化和羰基化形成。相比之下，4-OH-EPT的代谢在体外以双键形成、N-脱烷基化、羟基化和羰基化为主，在体内以羟基化或羰基化结合双键损失、羰基化、N-脱烷基化和羟基化为主。5-MeO-EPT在体外通过O-去甲基化、羟基化和N-脱烷基化进行代谢。通过在疑似EPT或4-OH-EPT中毒的人死后血液样本中鉴定4-OH-EPT的独特代谢物，证明了所表征的代谢物在法医案件工作中的实用性。
