Determination of naphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-018) in mouse blood and tissue after inhalation exposure to 'buzz' smoke by HPLC/MS/MS

The disposition of the cannabimimetic naphthalen‐1‐yl‐(1‐pentylindol‐3‐yl)methanone (JWH‐018) in mice following inhalation of the smoke of the herbal incense product (HIP) ‘Buzz’ is presented. A high‐pressure liquid chromatography with electrospray ionization triple quadrupole mass spectrometer (HPLC/MS/MS) method was validated for the analysis of JWH‐018 in the specimens using deuterated Δ⁹‐tetrahydrocannabinol (d₃‐THC) as the internal standard. JWH‐018 was isolated by cold acetonitrile liquid–liquid extraction. Chromatographic separation was performed on a Zorbaz eclipse XDB‐C₁₈ column. The assay was linear from 1 to 1000 ng/mL. Six C57BL6 mice were sacrificed 20 min after exposure to the smoke of 200 mg ‘Buzz’ containing 5.4% JWH‐018. Specimen concentrations of JWH‐018 were: blood, 54–166 ng/mL (mean 82 ± 42 ng/mL); brain, 316–708 ng/g (mean 510 ± 166 ng/g); and liver, 1370–3220 ng/mL (mean 1990 ± 752 ng/mL). The mean blood to brain ratio for JWH‐018 was 6.8 and ranged from 4.2 to 10.9. After exposure, the responses of the mice were consistent with cannabinoid receptor type 1 activity: body temperatures dropped 7.3 ± 1.1 °C, and catalepsy, hyperreflexia, straub tail and ptosis were observed. The brain concentrations and physiological responses are consistent with the hypothesis that the behavioral effects of ‘Buzz’ are attributable to JWH‐018. Copyright © 2012 John Wiley & Sons, Ltd.