Chemical synthesis, characterisation and in vitro and in vivo metabolism of the synthetic opioid MT-45 and it's newly identified fluorinated analogue 2F-MT-45 with metabolite confirmation in urine samples from known drug users

Craig McKenzie (Lead / Corresponding author), Oliver B. Sutcliffe (Lead / Corresponding author), Kevin Read, Stanley Scullion, Rafiu Epemolu, Daniel Fletcher, Anders Helander, Olof Beck, Alexia Rylski, Lysbeth Antonides, Jennifer Riley, Shannah Smith, Niamh Nic Daeid

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Purpose: The detection of a novel psychoactive substance, 2F-MT-45, a fluorinated analogue of the synthetic opioid MT-45, was reported in a single seized tablet. MT-45, 2F-, 3F- and 4F-MT-45 were synthesised and reference analytical data were reported. The in vitro and in vivo metabolisms of MT-45 and 2F-MT-45 were investigated. Method: The reference standards and seized sample were characterised using nuclear magnetic resonance spectroscopy, ultra-performance liquid chromatography–quadrupole time of flight mass spectrometry, gas chromatography–mass spectrometry, attenuated total reflectance-Fourier transform infrared spectroscopy and Raman spectroscopy. Presumptive tests were performed and physicochemical properties of the compounds determined. Metabolite identification studies using human liver microsomes, human hepatocytes, mouse hepatocytes and in vivo testing using mice were performed and identified MT-45 metabolites were confirmed in authentic human urine samples. Results: Metabolic pathways identified for MT-45 and 2F-MT-45 were N-dealkylation, hydroxylation and subsequent glucuronidation. The major MT-45 metabolites identified in human in vitro studies and in authenticated human urine were phase I metabolites and should be incorporated as analytical targets to existing toxicological screening methods. Phase II glucuronidated metabolites were present in much lower proportions. Conclusions: 2F-MT-45 has been detected in a seized tablet for the first time. The metabolite identification data provide useful urinary metabolite targets for forensic and clinical testing for MT-45 and allows screening of urine for 2F-MT-45 and its major metabolites to determine its prevalence in case work.

Original languageEnglish
Pages (from-to)359-374
Number of pages16
JournalForensic Toxicology
Issue number2
Early online date5 Apr 2018
Publication statusPublished - Jul 2018



  • Novel psychoactive substances
  • MT-45
  • 2F-MT-45
  • Metabolite profiles
  • Forensic Toxicology
  • Clinical Toxicology
  • Synthetic Opioids
  • analytical chemistry

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