In the US, different states have different laws for delta-9-THC products ranging from recreationally legal in some states to illegal in others. This opens the door for other isomers that exist in a legal gray area to be sold on the market for users to get psychoactive effects until the laws are introduced to regulate a specific isomer. A common isomer of delta-9-THC that also has psychoactive effects, is delta-8-THC. A few years ago, I wrote a blog about the resolution of the carboxy metabolites for delta-8-THC and delta-9-THC, which are the main metabolites formed in the body.
For drug testing, the carboxy-THC metabolite is historically the analyte used to determine cannabis usage. This compound has a long half-life and can be detected in urine or blood for several weeks in heavy consumers. This can pose a challenge when determining if a user is intoxicated at the time of incident or just a recent user. Today, labs are interested in the addition of the hydroxy metabolites, the intermediate between THC and the carboxylated metabolite. The intermediate is short lived but is useful in the determination of chronic usage and also when determining if a user is under the influence. A method was developed to include OH-8-THC and OH-9-THC as well as the parent compounds and the carboxy metabolites.
This method utilizes a Raptor FluoroPhenyl 100 x 3 mm, 2.7 µm column and isocratic mobile phase conditions with a 12-minute cycle time and achieves resolution of all three pairs of isomers. As cannabis legality grows and THC analogs hit the market, testing to determine intoxication at the time of incident will become paramount for drug testing. Is your lab currently running or interested in this application? Let us know in the comments below!
