Prevalence of carboxy-Δ⁸-tetrahydrocannabiniol in antidoping samples

Δ⁹-Tetrahydrocannabinol (Δ⁹-THC) is usually the primary psychoactive agent in cannabis preparations. Recently, products containing another isomer, Δ⁸-tetrahydrocannabinol (Δ⁸-THC), have become available for sale. Δ⁸-THC exists naturally in the cannabis plant at very low concentrations; hence, the Δ⁸-THC present in most of the above-mentioned products is likely to be manufactured synthetically. A surge in popularity of these products, coupled with little oversight to ensure purity and potency, has led to reports of adverse events. Workplace drug testing programs as well as many sporting organizations prohibit the use of cannabinoids. Carboxy-Δ⁹-THC (Δ⁹-THC-COOH) is the targeted urinary metabolite for detection of cannabis use. The proliferation of products containing Δ⁸-THC, which metabolizes to Δ⁸-THC-COOH, presents analytical complexity with respect to separation and quantification of the individual isomers as well as legal complexity with respect to lack of clarity around the legal status of Δ⁸-THC. This study aims to estimate the prevalence of Δ⁸-THC use in the athlete community by monitoring for Δ⁸-THC-COOH in samples collected for antidoping. A high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method was utilized to resolve Δ⁸ and Δ⁹-THC-COOH. One thousand samples with a presumptive Δ⁹-THC-COOH finding in routine screening were analyzed by the above LC-MS/MS method. Approximately 12% of samples contained Δ⁸-THC-COOH at relative abundances between 5% and 100% of total carboxy-THC content.