Up to now, little is known about the metabolic pathways of new fentanyl analogs that have recently emerged on the drug markets worldwide with high potential for producing addiction and severe adverse effects including coma and death. For some of the compounds, limited information on the metabolism has been published, however, for others so far no information is available. Considering the well characterized metabolism of the pharmaceutically used opioid fentanyl and the so far available data, the metabolism of the new fentanyl analogs can be anticipated to generally involve reactions like hydrolysis, hydroxylation (and further oxidation steps), N - and O -dealkylation and O -methylation. Furthermore, phase II metabolic reactions can be expected comprising glucuronide or sulfate conjugate formation. When analyzing blood and urine samples of acute intoxication cases or fatalities, the presence of metabolites can be crucial for confirmation of the uptake of such compounds and further interpretation. Here we present a review on the metabolic profiles of new fentanyl analogs responsible for a growing number of severe and fatal intoxications in the United States, Europe, Canada, Australia, and Japan in the last years, as assessed by a systematic search of the scientific literature and official reports.

BackgroundMetastasis is the leading cause of mortality in malignant diseases. Patients with metastasis often show reduced Lysophosphatidylcholine (LysoPC) plasma levels and treatment of metastatic tumour cells with saturated LysoPC species reduced their metastatic potential in vivo in mouse experiments. To provide a first insight into the interplay of tumour cells and LysoPC, the interactions of ten solid epithelial tumour cell lines and six leukaemic cell lines with saturated and mono-unsaturated LysoPC species were explored.MethodsLysoPC metabolism by the different tumour cells was investigated by a combination of cell culture assays, GC and MS techniques. Functional consequences of changed membrane properties were followed microscopically by detecting lateral lipid diffusion or cellular migration. Experimental metastasis studies in mice were performed after pretreatment of B16.F10 melanoma cells with LysoPC and FFA, respectively.ResultsIn contrast to the leukaemic cells, all solid tumour cells show a very fast extracellular degradation of the LysoPC species to free fatty acids (FFA) and glycerophosphocholine. We provide evidence that the formerly LysoPC bound FFA were rapidly incorporated into the cellular phospholipids, thereby changing the FA-compositions accordingly. A massive increase of the neutral lipid amount was observed, inducing the formation of lipid droplets. Saturated LysoPC and to a lesser extent also mono-unsaturated LysoPC increased the cell membrane rigidity, which is assumed to alter cellular functions involved in metastasis. According to that, saturated and mono-unsaturated LysoPC as well as the respective FFA reduced the metastatic potential of B16.F10 cells in mice. Application of high doses of liposomes mainly consisting of saturated PC was shown to be a suitable way to strongly increase the plasma level of saturated LysoPC in mice.ConclusionThese data show that solid tumours display a high activity to hydrolyse LysoPC followed by a very rapid uptake of the resulting FFA; a mechanistic model is provided. In contrast to the physiological mix of LysoPC species, saturated and mono-unsaturated LysoPC alone apparently attenuate the metastatic activity of tumours and the artificial increase of saturated and mono-unsaturated LysoPC in plasma appears as novel therapeutic approach to interfere with metastasis.

Since the beginning of the phenomenon of new psychoactive substances (NPS), synthetic cannabinoid receptor agonists (SCRAs) have been the largest and most prevalent subclass of these drugs in Europe. Many countries implemented specific legislation scheduling classes of substances defined on the basis of their chemical structure to reduce supply. We describe the identification and analytical characterization within the EU project ADEBAR plus of 1-(cyclobutylmethyl)-N-(2-phenylpropan-2-yl)-1Hindole-3-carboxamide which resulted in the formal notification through the Early Warning System of the European Monitoring Centre for Drug and Drug Addiction (EMCDDA). This is the first identification of this new SCRA worldwide and the analytical data was distributed (inter-)nationally right after identification in 2019. First, the substance was isolated from the herbal material using preparative high-performance liquid chromatography (HPLC). Structure elucidation and analytical characterization were performed using gas chromatography-mass spectrometry (GC-MS), gas chromatography-solid state infrared spectroscopy (GC-sIR), liquid chromatographyelectrospray ionization-quadrupole time of flight-mass spectrometry (LC-ESI-qToF-MS), Raman spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The new compound contains a cyclobutyl methyl group as a side chain and has not been described in any patent to our knowledge. Based on the semisystematic nomenclature of SCRAs, we propose Cumyl-CBMICA as a short name for the compound.

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Purpose5F-CUMYL-PEGACLONE is a recently emerged γ-carbolinone derived synthetic cannabinoid. The present study aimed to identify phase I metabolites to reliably prove consumption of the substance by urine analysis and to differentiate from the uptake of the non-fluorinated analog CUMYL-PEGACLONE.MethodsFor metabolite characterization, phase I metabolites were analyzed by liquid chromatography–high resolution mass spectrometry after incubation with pooled human liver microsomes. Reliability of the biomarkers was evaluated by analysis of human urine samples (n = 20) by liquid chromatography–triple quadrupole tandem mass spectrometry. Sample preparation included β-glucuronidase treatment followed by liquid-liquid extraction.ResultsIn total, 15 metabolites were detected in vivo and characterized. Metabolic reactions were primarily observed at the γ-carbolinone core and the 5-fluoropentyl chain, and included N-dealkylation, hydroxylation, hydrolytic defluorination, formation of a dihydrodiol, oxidation to the pentanoic acid metabolite and formation of the propionic acid metabolite. Six of these metabolites were identical with phase I metabolites of CUMYL-PEGACLONE, which must be considered for interpretation of analytical findings in urine samples.Conclusions5F-CUMYL-PEGACLONE was subject to extensive metabolism in humans. The propionic acid metabolite was the most abundant metabolite in all urine samples and should be targeted when maximum sensitivity is needed (e.g., drug abstinence control). However, this metabolite also occurs in the biotransformation of the non-fluorinated analog and is, therefore, not a compound-specific marker. For differentiation, a metabolite hydroxylated at the γ-carbolinone core showed to be the most reliable marker and should be used as an additional target analyte.Electronic supplementary materialThe online version of this article (10.1007/s11419-018-0447-4) contains supplementary material, which is available to authorized users.

Synthetic cannabinoids (SCs) are a structurally diverse class of new psychoactive substances. Most SCs used for recreational purposes are based on indole or indazole core structures. EG-018 (naphthalen-1-yl(9-pentyl-9H-carbazol-3-yl)methanone), EG-2201 ((9-(5-fluoropentyl)-9H-carbazol-3-yl)(naphthalen-1-yl)methanone), and MDMB-CHMCZCA (methyl 2-(9-(cyclohexylmethyl)-9H-carbazole-3-carboxamido)-3,3-dimethylbutanoate) are 3 representatives of a structural subclass of SCs, characterized by a carbazole core system. In vitro and in vivo phase I metabolism studies were conducted to identify the most suitable metabolites for the detection of these substances in urine screening. Detection and characterization of metabolites were performed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) and liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry (LC-ESI-QToF-MS). Eleven in vivo metabolites were detected in urine samples positive for metabolites of EG-018 (n = 8). A hydroxypentyl metabolite, most probably the 4-hydroxypentyl isomer, and an N-dealkylated metabolite mono-hydroxylated at the carbazole core system were most abundant. In vitro studies of EG-018 and EG-2201 indicated that oxidative defluorination of the 5-fluoropentyl side chain of EG-2201 as well as dealkylation led to common metabolites with EG-018. This has to be taken into account for interpretation of analytical findings. A differentiation between EG-018 and EG-2201 (n = 1) uptake is possible by the detection of compound-specific in vivo phase I metabolites evaluated in this study. Out of 30 metabolites detected in urine samples of MDMB-CHMCZCA users (n = 20), a metabolite mono-hydroxylated at the cyclohexyl methyl tail is considered the most suitable compound-specific consumption marker while a biotransformation product of mono-hydroxylation in combination with hydrolysis of the terminal methyl ester function provides best sensitivity due to its high abundance.

Indole-, indazole-, or azaindole-based synthetic cannabinoids (SCs), bearing a cumyl substituent are a widespread, recreationally used subgroup of new psychoactive substances (NPS). The latest cumyl-derivative, CUMYL-PEGACLONE, emerged in December 2016 on the German drug market. The substance features a novel γ-carboline core structure, which is most likely synthesized to bypass generic legislative approaches to control SCs by prohibiting distinct core structures. Using liquid chromatography-tandem mass spectrometry and liquid chromatography-high resolution mass spectrometry techniques, the main in vivo phase I metabolites of this new substance were detected. A pooled human liver microsome assay was applied to generate in vitro reference spectra of CUMYL-PEGACLONE phase I metabolites. Additionally, 30 urine samples were investigated leading to 22 in vivo metabolites. A metabolite mono-hydroxylated at the γ-carbolinone core system and a metabolite with an additional carbonyl group at the pentyl side chain were evaluated as highly specific and sensitive markers to proof CUMYL-PEGACLONE uptake. Moreover, 3 immunochemical assays commonly used for SC screening in urine were tested for their capability of detecting the new drug but failed due to insufficient cross-reactivity.

Novel synthetic opioids and benzodiazepines are an emerging trend on the narcotic drugs market. We present a lethal case of U-47700 and flubromazepam poisoning. A 24-year-old man suffered apnoea after the consumption of the synthetic opioid U-47700 in combination with the benzodiazepine flubromazepam. After reanimation and hospital admission, hypoxic cerebral damage and severe brain oedema were stated. Six days after admission, mechanical ventilation was discontinued, and the patient died. Seven blood serum samples and one urine sample collected during the hospitalisation were analysed by liquid chromatography-tandem mass spectrometry. In the sample collected 42 minutes after admission, the concentrations of U-47700 and flubromazepam were 370 and 830 ng/mL, respectively. Three days later, the concentrations of U-47700 and flubromazepam dropped to 4.2 and 280 ng/mL, respectively. The resulting concentration-time-curves allowed calculating a U-47700 elimination half-life of approximately six hours and confirmed the previously reported flubromazepam elimination half-life of around 100 hours. In the presented case, intoxication by the synthetic opioid U-47700 with a contribution of flubromazepam can be assumed as the cause of death. The concentration-time curves allow an estimation of the clinical course of similar cases. Flubromazepam may lead to prolonged central-nervous depressant effects.