LAUSR

The aim of this study was to identify new markers of deschloro-N-ethyl-ketamine (O-PCE), a ketamine analogue that has been involved in acute intoxications with sever outcomes including death and whose metabolism has never been studied before. In vitro study after 2h incubation with pooled human liver microsomes (HLMs) cross-checked by the analysis of urine and hair from a 43 years-old O-PCE user (male) were performed by liquid chromatography-high resolution mass spectrometry (LC-HRMS). Acquired Data were processed by the Compound Discoverer® software and a full metabolic profile of O-PCE was proposed. In total, 15 metabolites were identified, 10 were detected in vitro (HLMs) and confirmed in vivo (urine and/or hair), 2 were present only in HLMs while the remaining three metabolites were identified only in biological specimens. While O-PCE was no longer detected in urine, 9 metabolites were identified allowing to increase its detection window. In descending order of metabolites abundance, we suggest using 2-en-PCA-N-Glu (34%, 1st ), M3 (16%, 2nd ), O-PCA-N-Glu (15.4%, 3rd ), OH-O-PCE (15%, 4th ) and OH-PCE (11.9%, 5th ) as target metabolites to increase the detection window of O-PCE in urine. In hair, 9 metabolites were identified, OH-PCA was the major compound (78%) with a relevant metabolite to parent drug ratio (= 6) showing its good integration into hair and making it the best marker for long-term monitoring of O-PCE exposure.