Groth Olwen C, Pi Anaëlle, Jensen Andres E, Reckel Frank, Hodecek Jiri, Kori Yahia Abderrahmane, Rahaus Susan, Villet Martin H, Graw Matthias
Institute of Forensic Medicine, Ludwig-Maximilians-Universität in Munich, Nussbaumstrasse 26, 80336, Munich, Germany.
University Côte d'Azur, 06108, Nice, France.
Forensic Toxicol. 2025 May 26. doi: 10.1007/s11419-025-00728-1.
A principal objective of forensic entomotoxicology is to apply insect specimens for post-mortem toxicological analysis. Successful identification of drugs in necrophagous insects may depend on pharmacokinetic processes occurring in larvae. We thus applied a model system involving Lucilia sericata (Meigen, 1826) (Diptera, Calliphoridae) to investigate pharmacokinetics of diazepam in larvae in vitro, followed by a field experiment with Göttingen Minipigs.
Lucilia sericata larvae were fed one of four diazepam concentrations at constant temperature, sampled regularly, and analysed for diazepam and metabolites by liquid chromatography tandem mass spectrometry (LC-MS/MS). Two Göttingen Minipigs of 60 kg each were euthanised one hour after oral administration of 25 mg/kg diazepam and placed outdoors. While available, samples of peripheral blood, cardiac blood, liver, and fly larvae were collected over 70 days. Extracts from porcine samples and larvae were analysed by LC-MS/MS. Some larvae were bred to adulthood and identified morphologically together with 718 larvae.
Oxazepam was a primary metabolite of diazepam in L. sericata larvae. The most prevalent fly species on minipig carcasses were Lucilia caesar (Linnaeus, 1758) (Diptera, Calliphoridae) and Lucilia illustris (Meigen, 1826) (Diptera, Calliphoridae). Diazepam and metabolites were detected in all larval samples, even weeks after porcine samples were unacquirable due to post-mortem decomposition. Ratios of oxazepam and nordazepam to diazepam concentrations in larvae were significantly higher than in associated porcine samples, confirming metabolism in larvae.
These findings are relevant to forensic casework, as there is potential for misinterpreting that the deceased consumed oxazepam or nordazepam rather than diazepam. This caution may also apply to other drugs that can form through metabolism in larvae.
法医昆虫毒理学的一个主要目标是将昆虫标本应用于死后毒理学分析。能否成功鉴定食尸性昆虫体内的药物可能取决于幼虫体内发生的药代动力学过程。因此，我们应用了一个涉及丝光绿蝇（Lucilia sericata，Meigen，1826）（双翅目，丽蝇科）的模型系统，在体外研究地西泮在幼虫体内的药代动力学，随后对哥廷根小型猪进行了一项野外实验。
将丝光绿蝇幼虫在恒温下喂食四种地西泮浓度之一，定期取样，并通过液相色谱串联质谱法（LC-MS/MS）分析地西泮及其代谢物。两只体重各为60千克的哥廷根小型猪在口服25毫克/千克地西泮1小时后实施安乐死，并放置在户外。在70天内，只要有样本，就收集外周血、心脏血、肝脏和蝇幼虫样本。通过LC-MS/MS分析猪样本和幼虫的提取物。一些幼虫饲养至成年，并与718只幼虫一起进行形态学鉴定。
奥沙西泮是丝光绿蝇幼虫体内地西泮的主要代谢物。小型猪尸体上最常见的蝇类物种是红头丽蝇（Lucilia caesar，Linnaeus，1758）（双翅目，丽蝇科）和亮绿蝇（Lucilia illustris，Meigen，1826）（双翅目, 丽蝇科）。在所有幼虫样本中均检测到地西泮及其代谢物，甚至在猪样本因死后分解无法获取数周后仍能检测到。幼虫体内奥沙西泮和去甲地西泮与地西泮浓度的比值显著高于相关猪样本中的比值，证实了幼虫体内的代谢作用。
这些发现与法医案件工作相关，因为存在误判死者服用的是奥沙西泮或去甲地西泮而非地西泮的可能性。这种谨慎态度可能也适用于其他可通过幼虫代谢形成的药物。
