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. HC‐COOH isomers that coeluted during GCMS screening were resolved chromatographically by LC. 1000 samples with potential THC‐COOH in GCMS screening were reanalyzed by LCMS. Δ8 THC‐COOH was present in 12% samples and made up between 5% and 100% of the total THC‐COOH content.