Monitoring of urinary metabolites of JWH-018 and JWH-073 in legal cases

Due to their cannabis-like effects, synthetic cannabinoids have attracted much public attention since 2008. Thus, elucidation of the metabolic pattern and the detection of the intake of these drugs have been of major concern. In order to suggest appropriate urinary biomarkers to prove JWH-018 or JWH-073 intake, we selected the major metabolites of JWH-018 and JWH-073, namely (ω)-, (ω-1)-hydroxy, carboxy and 6-hydroxyindole metabolites, and validated a method for the quantification of these metabolites using solid-phase extraction based on LC–MS/MS analysis. Authentic urine specimens obtained from drug offenders were screened via a synthetic cannabinoid ELISA kit and were analyzed by LC–MS/MS for confirmation. Twenty-one out of a total of 52 samples (40%) were found positive for at least one metabolite of JWH-018 or JWH-073. N-pentyl hydroxy metabolites of JWH-018 and carboxy metabolites of JWH-018 and JWH-073 were detected in all positive samples. However, the rest of the metabolites were either not detected or only a small amount of them were found. A considerable variation was observed in the concentration ratio of (ω) and (ω-1)-hydroxy metabolites of JWH-018. Based on the results, it may have some pitfalls to determine the ingestion of specific synthetic cannabinoids by detecting a few metabolites, considering the continuous emergence of structurally related synthetic cannabinoids. Thus, use of synthetic cannabinoids should be proven carefully through comprehensive investigation of analytical results of biological specimens.