Urinary Excretion Profile of Cannabinoid Analytes Following Acute Administration of Oral and Vaporized Cannabis in Infrequent Cannabis Users

Traditionally, smoking has been the predominant method for administering cannabis, but alternative routes of administration have become more prevalent. Additionally, research examining urinary cannabinoid excretion profiles has primarily focused on 11-nor-9-carboxy-9-tetrahydrocannabinol (9-THC-COOH), a metabolite of 9-tetrahydrocannabinol (9-THC), as the primary analyte. The aim of the current study was to characterize the urinary excretion profile of 9-THC-COOH, 9-THC, 8-tetrahydrocannabinol (8-THC), 11-hydroxy-9-tetrahydrocannabinol (11-OH-9-THC), 9-tetrahydrocannabivarin (THCV), 11-nor-9-tetrahydrocannabivarin-9-carboxlic acid (THCV-COOH), cannabidiol (CBD), cannabinol (CBN) and 8,11-dihydroxytetrahydrocannabinol (8,11-diOH-9-THC) following controlled administration of both oral and vaporized cannabis. Participants (n = 21, 11 men/10 women) who were infrequent cannabis users ingested cannabis-containing brownies (0, 10 and 25 mg 9-THC) and inhaled vaporized cannabis (0, 5 and 20 mg 9-THC) across six double-blind outpatient sessions. Urinary concentrations of 9-THC analytes were measured at baseline and for 8 h after cannabis administration. Sensitivity, specificity and agreement between the three immunoassays (IAs) for 9-THC-COOH (cutoffs of 20, 50 and 100 ng/mL) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) analyses (confirmatory cutoff concentrations of 15 ng/mL) were assessed. Urinary concentrations for 9-THC-COOH, 9-THC, 11-OH-9-THC, THCV, CBN and 8,11-diOH-9-THC all peaked at 5-6 h and 4 h following oral and vaporized cannabis administration, respectively. At each active dose, median maximum concentrations (Cmax) for detected analytes were quantitatively higher after oral cannabis administration compared to vaporized. Using current recommended federal workplace drug-testing criteria (screening via IA with a cutoff of ≥50 ng/mL and confirmation via LC-MS-MS at a cutoff of ≥15 ng/mL), urine specimens tested positive for 9-THC-COOH in 97.6% of oral sessions and 59.5% of vaporized sessions with active 9-THC doses. These data indicate that while 9-THC-COOH may serve as the most consistent confirmatory analyte under the current drug-testing guidelines, future work examining 11-OH-9-THC under similar parameters could yield an alternative analyte that may be helpful in distinguishing between licit and illicit cannabis products.