In vitro metabolism studies on mephedrone and analysis of forensic cases

TY - JOUR

T1 - In vitro metabolism studies on mephedrone and analysis of forensic cases

AU - Pedersen, Anders Just

AU - Reitzel, Lotte Ask

AU - Johansen, Sys Stybe

AU - Linnet, Kristian

N1 - Copyright © 2012 John Wiley & Sons, Ltd.

PY - 2013/6

Y1 - 2013/6

N2 - 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/MSE 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 51μg/kg for mephedrone, and from not detected to 9μg/kg for hydroxytolyl-mephedrone. In one case, urine concentrations were also determined to be 700μg/kg for mephedrone and 190μg/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.

AB - 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/MSE 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 51μg/kg for mephedrone, and from not detected to 9μg/kg for hydroxytolyl-mephedrone. In one case, urine concentrations were also determined to be 700μg/kg for mephedrone and 190μg/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.

U2 - 10.1002/dta.1369

DO - 10.1002/dta.1369

M3 - Journal article

C2 - 22573603

SN - 1942-7603

VL - 5

SP - 430

EP - 438

JO - Drug Testing and Analysis

JF - Drug Testing and Analysis

IS - 6

ER -