Detection of JWH-018 metabolites in smoking mixture post-administration urine

Smoking mixtures containing the cannabimimetic indoles may still be available over-the-counter in several countries. Due to the high affinity of these compounds to the cannabinoid receptors, their effective dose is lower than that of the marijuana products resulting in a low concentration of the excreted metabolites accompanied by a higher psychoactive potency. Up to now the in vivo metabolism of the cannabimimetic indoles seems to be insufficiently investigated and no data have been published on an assay of JWH-018 in urine. In this publication the urinary metabolites of JWH-018 are reported. Using gas and liquid chromatography combined with tandem mass spectrometry two main monohydroxylated metabolites were identified in the forensic urine samples. Based on the differences in their electron ionization MS/MS spectra it is supposed that one is formed by hydroxylation of the indole ring whilst the other by hydroxylation of the N-alkyl chain. The main metabolites are almost completely glucuroconjugated, whereas minor ones (N-despentyl hydroxy-, carboxy-, dihydroxy-, and reduced di- and trihydroxy metabolites) were also present in the free fraction. The parent compound was not detected in urine.