Pharmacokinetic properties of the synthetic cannabinoid JWH‐018 in oral fluid after inhalation

Each year, synthetic cannabinoids occur in high numbers on the illicit drug market, but data on their detectability are rarely available. A pilot study was performed to assess adverse effects of JWH‐018, which is one of the oldest and best known synthetic cannabinoids. Oral fluid has been evaluated as a specimen for drug monitoring. Six subjects inhaled smoke derived from 2 and 3 mg JWH‐018. The drug and 10 of its metabolites were analyzed in oral fluid samples collected during the following 12 hours using the Quantisal collection device by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Maximum concentrations of JWH‐018 reached 2.2–2036 (median 25.7) ng/mL after inhalation and decreased during the next hour to only 0.08–8.42 (median 0.89) ng/mL. Metabolites were not found. During the elimination phase (median half‐life 1.69 hours), detection of the drug over 6–12 hours (median 8 hours) after inhalation was achieved (0.024 ng/mL limit of quantification). Oral fluid/serum ratios varied considerably intra‐ and inter‐individually in a range of 0.05–555 (median 1.38). The detection of JWH‐018 in oral fluid requires high analytical sensitivity even 1 hour after inhalation. The pharmacokinetic properties of inhaled JWH‐018 are similar to those of THC. Times for detection are typically less than 12 hours. High variability of the oral fluid/serum ratio precludes extrapolation of oral fluid concentrations to blood.