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.