Cannabinoid disposition in oral fluid after controlled cannabis smoking in frequent and occasional smokers.Drug Test Anal. 2014 Oct; 6(10):1002-10.DT
Oral fluid (OF) is an increasingly popular alternative matrix for drug testing, with cannabinoids being the most commonly identified illicit drug. Quantification of multiple OF cannabinoids and understanding differences in OF cannabinoid pharmacokinetics between frequent and occasional smokers improve test interpretation. The new Oral-Eze® OF collection device has an elution buffer that stabilizes analytes and improves drug recovery from the collection pad; however, its performance has not been independently evaluated. After controlled smoking of a 6.8% Δ(9) -tetrahydrocannabinol (THC) cannabis cigarette by frequent and occasional smokers, OF was collected with the Oral-Eze device for up to 30 h. Samples were analyzed for multiple cannabinoids by a validated 2D-GC-MS method. Frequent smokers had significantly greater OF THCCOOH concentrations than occasional smokers at all times, and showed positive results for a significantly longer time. We evaluated multiple cannabinoid cut-offs; the shortest last detection times were observed when THC ≥ 1 μg/L was combined with CBD or CBN ≥ 1 μg/L. With these cut-offs, last detection times(1-13.5 h) were not significantly different between groups, demonstrating suitability for short-term cannabinoid detection independent of smoking history. Cut-offs utilizing THC alone or combined with THCCOOH showed significantly different last detection times between groups. The widest detection windows were observed with THC ≥ 1 or 2 μg/L or THCCOOH ≥ 20 ng/L. Our data illustrate the effectiveness of the Oral-Eze® device for OF collection, the impact of self-administered smoked cannabis history on OF cannabinoid results, and the ability to improve interpretation and tailor OF cannabinoid cut-offs to fulfill the detection window needs of a given program.