Cannabinoid disposition in oral fluid after controlled vaporizer administration with and without alcohol

Oral fluid (OF) is an advantageous matrix for cannabis detection, with on-site tests available for roadside drug-impaired driver screening. Limited data exist for device performance following consumption of vaporized cannabis, which reduces exposure to harmful combustion by-products. We assessed cannabinoid OF disposition, with and without alcohol, and evaluated on-site Drager® DrugTest 5000 performance (Drager) following controlled vaporization of cannabis. Forty-three cannabis smokers (≥1×/3 months, ≤3 days/week) reported 10–16 h prior to dosing, and drank placebo or low-dose alcohol [target ~0.065 % peak breath-alcohol concentration (BrAC)] 10 min prior to inhaling 500 mg of placebo, low-dose [2.9 % ∆9-tetrahydrocannabinol (THC)], or high-dose (6.7 % THC) vaporized cannabis (within-subjects; six possible alcohol–cannabis combinations; 19 completers). BrAC readings and OF (Quantisal™, Drager) were collected before and up to 8.3 h post-dose. Median [range] maximum OF concentrations (C max) for low and high doses (no alcohol, N = 19) were 848 [32.1–18,230] and 764 [25.1–23,680] µg/l THC; 6.0 [0–100] and 26.8 [1.0–1106] µg/l cannabidiol; 54.4 [1.8–941] and 29.7 [0–766] µg/l cannabinol; and 24.1 [0–686] and 18.0 [0–414] ng/l 11-nor-9-carboxy-THC (THCCOOH). Lack of significant differences in THC concentration between low doses and high doses indicated that participants may have titrated doses. THC, cannabidiol and cannabinol C max values were immediately post-inhalation, but metabolite THCCOOH t max showed interindividual variability. Concurrent alcohol did not affect OF cannabinoid concentrations or on-site test sensitivity. With a THC confirmation cutoff of 5 µg/l, Drager sensitivity, specificity, and efficiency were 60.8, 98.2, and 82.5 %. Drager had lower sensitivity after 6.7 % THC vaporization (53.8 %, THC ≥2 µg/l confirmation cutoff) than reported following smoking a 6.8 % THC cigarette, but high specificity (99.3 %) and comparable efficiency (65.0 %). Vaporized THC bioavailability may be lower than that when smoked. Confirmation cutoff, time course, intake histories, and additional cannabinoid analytes also affect OF interpretation.