Postmortem examination and toxicological analysis for acute metonitazene intoxication in Japan: A case report

Identification of N-pyrrolidino protonitazene in powders sold as heroin and associated with overdose clusters in Dublin and Cork, Ireland

Synthetic opioids have been associated globally with adverse effects in drug users. The nitazene group of drugs is a relatively new addition to the synthetic opioid class emerging in Europe in 2019. Some nitazenes have been shown to be more potent than fentanyl. Overdose clusters in heroin users in Dublin (57 cases) and Cork (20 cases), Ireland, in November and December 2023, respectively, prompted a rapid response from a number of Irish laboratories to identify the substance(s) of concern. Light brown (tan) powders were obtained from cases associated with overdoses, and the results from these analyses by collaboration of four laboratories are reported here. The samples were found to contain N-pyrrolidino protonitazene (protonitazepyne), caffeine, paracetamol, benzoic acid and mannitol.

Method development for the quantification of nine nitazene analogs and brorphine in Dried Blood Spots utilizing liquid chromatography - tandem mass spectrometry

The detection of nitazenes in biological fluids is increasingly needed as they are repeatedly reported in intoxication and overdose cases. A simple method for the quantification of low levels of nine nitazene analogs and brorphine in Dried Blood Spots (DBS) was developed and validated. 10 μL of spiked whole blood is deposited on a Capitainer®B card and allowed to dry. The spot is punched out, and extracted with 500 μL methanol:acetonitrile (3:1 v/v) added with 1.5 μL of fentanyl-D5 as the internal standard. After stirring, sonication, and centrifugation of the vial, the solvent is dried under nitrogen, the extract is reconstituted in 30 μL methanol, and 1 μL is injected into a UHPLC-MS/MS instrument. The method validation showed linear calibration in the 1-50 ng/mL range, LOD values ranging between 0.3 ng/mL (isotonitazene) and 0.5 ng/mL (brorphine), average CV% and bias% within 15 % and 10 % for all compounds, respectively. The matrix effect due to blood and filter paper components was within 85-115 % while recovery was between 15-20 %. Stability tests against time and temperature showed no significant variations for storage periods up to 28 days. Room temperature proved to represent the best samples storage conditions. UHPLC-MS/MS proved capable to reliably identify all target analytes at low concentration even in small specimen volumes, as those obtained from DBS cards, which in turn confirmed to be effective and sustainable micro-sampling devices. This procedure improves the efficiency of toxicological testing and provides an innovative approach for the identification of the nitazene class of illicit compounds.