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Vandeputte MM, Stove CP. In vitro μ-opioid receptor activation potential of U10 and β-U10, positional isomers of the synthetic opioid naphthyl U-47700. Drug Test Anal 2024; 16:323-326. [PMID: 37482925 DOI: 10.1002/dta.3554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/25/2023]
Abstract
New synthetic opioids (NSOs) with diverse chemical structures continue to appear on recreational drug markets worldwide. U-type opioids have become one of the largest groups of non-fentanyl-related NSOs. Starting in 2020, a previously unreported U-compound coined "β-U10" (2-naphthyl U-47700; N-[2-(dimethylamino)cyclohexyl]-N-methylnaphthalene-2-carboxamide) was identified in Australia and the United States. β-U10 is a positional isomer of α-U10 (1-naphthyl U-47700), more commonly known as "U10." Here, the first comparative in vitro pharmacological characterization of naphthyl U-47700 (U10 and β-U10), together with the structural analogue U-47700 and fentanyl, is reported. Application of a cell-based μ-opioid receptor (MOR) activation (β-arrestin 2 recruitment) assay demonstrated β-U10 (EC50 = 348 nM; Emax = 150% vs. hydromorphone) to be less potent than U-47700 (EC50 = 116 nM; Emax = 154%) and fentanyl (EC50 = 9.35 nM; Emax = 146%) but considerably more active than the α-isomer (EC50 value in the μM range). For the latter, maximum receptor activation could not be reached at 100 μM. The difference in MOR activation potential for U10 and β-U10 stresses the importance of (analytical) differentiation between closely related analytes. The emergence of β-U10 on the recreational drug market is an example of the continuing emergence of non-fentanyl-related NSOs and further emphasizes the need to closely monitor fluctuations in the drug supply.
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Affiliation(s)
- Marthe M Vandeputte
- Laboratory of Toxicology, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - Christophe P Stove
- Laboratory of Toxicology, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
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West H, Fitzgerald JL, Hopkins KL, Leeming MG, DiRago M, Gerostamoulos D, Clark N, Dietze P, White JM, Ziogas J, Reid GE. Trace Residue Identification, Characterization and Longitudinal Monitoring of the Novel Synthetic Opioid β-U10, from Discarded Drug Paraphernalia. Drug Test Anal 2022; 14:1576-1586. [PMID: 35562123 PMCID: PMC9542064 DOI: 10.1002/dta.3284] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/01/2022] [Accepted: 05/10/2022] [Indexed: 11/08/2022]
Abstract
Empirical data regarding dynamic alterations in illicit drug supply markets in response to the COVID-19 pandemic, including the potential for introduction of novel drug substances and/or increased poly-drug combination use at the 'street' level, i.e., directly proximal to the point of consumption, is currently lacking. Here, a high-throughput strategy employing ambient ionization-mass spectrometry is described for the trace residue identification, characterization and longitudinal monitoring of illicit drug substances found within >6,600 discarded drug paraphernalia (DDP) samples collected during a pilot study of an early warning system for illicit drug use in Melbourne, Australia from August 2020-February 2021, while significant COVID-19 lockdown conditions were imposed. The utility of this approach is demonstrated for the de novo identification and structural characterization of β-U10, a previously unreported naphthamide analogue within the 'U-series' of synthetic opioid drugs, including differentiation from its α-U10 isomer without need for sample preparation or chromatographic separation prior to analysis. Notably, β-U10 was observed with 23 other drug substances, most commonly in temporally distinct clusters with heroin, etizolam and diphenhydramine, and in a total of 182 different poly-drug combinations. Longitudinal monitoring of the number and weekly 'average signal intensity' (ASI) values of identified substances, developed here as a semi-quantitative proxy indicator of changes in availability, relative purity and compositions of street level drug samples, revealed that increases in the number of identifications and ASI for β-U10 and etizolam coincided with a 50% decrease in the number of positive detections and an order of magnitude decrease in the ASI for heroin.
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Affiliation(s)
- Henry West
- School of Chemistry, The University of Melbourne, Parkville, Australia
| | - John L Fitzgerald
- School of Social and Political Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Katherine L Hopkins
- School of Chemistry, The University of Melbourne, Parkville, Australia.,School of Social and Political Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Michael G Leeming
- Melbourne Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Matthew DiRago
- Victorian Institute of Forensic Medicine, Southbank, Victoria, Australia.,Department of Forensic Medicine, Monash University, Clayton, Victoria, Australia
| | - Dimitri Gerostamoulos
- Victorian Institute of Forensic Medicine, Southbank, Victoria, Australia.,Department of Forensic Medicine, Monash University, Clayton, Victoria, Australia
| | - Nicolas Clark
- North Richmond Community Health, Richmond, Victoria, Australia.,Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Paul Dietze
- National Drug Research Institute and enAble Institute, Curtin University, Melbourne, Victoria, Australia.,Disease Elimination Program, Burnet Institute, Melbourne, Victoria, Australia
| | - Jonathan M White
- School of Chemistry, The University of Melbourne, Parkville, Australia
| | - James Ziogas
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
| | - Gavin E Reid
- School of Chemistry, The University of Melbourne, Parkville, Australia.,Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
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Feeney W, Moorthy AS, Sisco E. Spectral trends in GC-EI-MS data obtained from the SWGDRUG mass spectral library and literature: A resource for the identification of unknown compounds. Forensic Chem 2020; 31:10.1016/j.forc.2022.100459. [PMID: 36578315 PMCID: PMC9793444 DOI: 10.1016/j.forc.2022.100459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Rapid identification of new or emerging psychoactive substances remains a critical challenge in forensic drug chemistry laboratories. Current analytical protocols are well-designed for confirmation of known substances yet struggle when new compounds are encountered. Many laboratories initially attempt to classify new compounds using gas chromatography-electron ionization-mass spectrometry (GC-EI-MS). Though there is a large body of research focused on the analysis of illicit substances with GC-EI-MS, there is little high-level discussion of mass spectral trends for different classes of drugs. This manuscript compiles literature information and performs simple exploratory analyses on evaluated GC-EI-MS data to investigate mass spectral trends for illicit substance classes. Additionally, this work offers other important aspects: brief discussions of how each class of drugs is used; illustrations of EI mass spectra with proposed structures of commonly observed ions; and summaries of mass spectral trends that can help an analyst classify new illicit compounds.
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Affiliation(s)
- William Feeney
- Corresponding author at: Surface and Trace Chemical Analysis Group, Material Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. (W. Feeney)
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