title: In vitro metabolism studies on mephedrone and analysis of forensic cases.
abstract: The stimulant designer drug mephedrone is a derivative of cathinone - a monoamine alkaloid found in khat - and its effect resembles that of 3,4-Methylenedioxymethamphetamine (MDMA). Abuse of mephedrone has been documented since 2007; it was originally a 'legal high' drug, but it has now been banned in most Western countries. Using cDNA-expressed CYP enzymes and human liver microsomal preparations, we found that cytochrome P450 2D6 (CYP2D6) was the main responsible enzyme for the in vitro Phase I metabolism of mephedrone, with some minor contribution from other NAPDH-dependent enzymes. Hydroxytolyl-mephedrone and nor-mephedrone were formed in vitro, and the former was purified and identified by nuclear magnetic resonance (NMR). In four forensic traffic cases where mephedrone was detected, we identified hydroxytolyl-mephedrone and nor-mephedrone again; as well as 4-carboxy-dihydro-mephedrone, which has been previously described; and two new metabolites: dihydro-mephedrone and 4-carboxy-mephedrone. Fragmentation patterns for all detected compounds were determined by a UPLC-QTOF/MS(E) system, and a fragmentation pathway via a conjugated indole structure was proposed for most of the metabolites. Blood concentrations in the forensic traffic cases ranged from 1 to 51 µg/kg for mephedrone, and from not detected to 9 µg/kg for hydroxytolyl-mephedrone. In one case, urine concentrations were also determined to be 700 µg/kg for mephedrone and 190 µg/kg for hydroxytolyl-mephedrone. All compounds were detected or quantified with an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) system and an ultra performance liquid chromatography-time of flight/mass spectrometry (UPLC-TOF/MS) system.
authors.affiliation: Department of Forensic Medicine, Faculty of Health Sciences, University of Copenhagen, Denmark. anders.pedersen@forensic.ku.dk
authors.forename: Anders Just
authors.initials: AJ
authors.lastname: Pedersen
authors.forename: Lotte Ask
authors.initials: LA
authors.lastname: Reitzel
authors.forename: Sys Stybe
authors.initials: SS
authors.lastname: Johansen
authors.forename: Kristian
authors.initials: K
authors.lastname: Linnet
mesh_terms: D000697:Central Nervous System Stimulants / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism; D015198:Designer Drugs / Q000378:metabolism* / Q000493:pharmacokinetics; D005554:Forensic Medicine; D006801:Humans; D013287:Illicit Drugs / Q000097:blood / Q000378:metabolism* / Q000652:urine; D008694:Methamphetamine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000652:urine; D008862:Microsomes, Liver / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D000697:Central Nervous System Stimulants; D015198:Designer Drugs; D013287:Illicit Drugs; D008694:Methamphetamine; C548233:mephedrone; D019389:Cytochrome P-450 CYP2D6