Identification of 11-nor-∆8-Tetrahydrocannabinol-9-Carboxylic Acid in Postmortem Urine

Laws concerning the growing, selling and consuming of cannabis and its related products have been changing considerably over the last few years. The legalization of hemp in 2018 sparked an interest in ∆9-tetrahydrocannabinol (∆9-THC) isomers and analogs that are derived from hemp and sold with minimal oversight. One example is ∆8-tetrahydrocannabinol (∆8-THC). Although less potent than ∆9-THC, ∆8-THC is gaining popularity and can easily be found where cannabis-related products are sold. The Forensic Toxicology Laboratory at the University of Florida routinely tested decedents for 11-nor-∆9-tetrahydrocannabinol-9-carboxylic acid (∆9-THC-acid), the primary metabolite of ∆9-THC. Urine samples from ∼900 decedents were received by the laboratory between mid-November 2021 and mid-March 2022 and subjected to CEDIA™ immunoassay testing. Subsequent confirmation of 194 presumptive positive samples was performed by gas chromatography--mass spectrometry. A peak eluting immediately after ∆9-THC-acid was identified as 11-nor-∆8-tetrahydrocannabinol-9-carboxylic acid (∆8-THC-acid), a metabolite of ∆8-THC, in 26 of those samples (13%). Six of the samples were positive for ∆8-THC-acid only. Other toxicological findings were consistent with poly-drug use including fentanyl/fentanyl analogs, ethanol, cocaine and methamphetamine. There has been an emergence of ∆8-THC use as indicated by the presence of ∆8-THC-acid in 26 of 194 presumptive positive cases during a four-month period. The majority of individuals were White males with a history of drug and/or alcohol use. ∆9-THC-acid, as well as other drugs, was often present. Given the psychoactive potential and availability of ∆8-THC, monitoring ∆8-THC-acid in decedents is important to characterize the risk and prevalence of ∆8-THC use.