We return to a discussion of delta-8-tetrahydrocannabinol. Let’s discuss “isomers”: how D-8 is an isomer of D-9-tetrahydrocannabinol, the other double bond isomers of THC, and some of the metabolites of these isomers.
If you look closely, you can see the difference between D-8 and D-9 THC. It is the position of the double bond next to the appended methyl group at C9. See below.
Delta 8 THC
Delta-8 THC is the most thermodynamically stable isomer of THC. That means nature wants the that configuration. An isomer of a molecule contains the same elements (C, H, O) but its structure is different. A good look at D-8 vs D-9 shows that they have the same chemical composition, but different structures. Very close to being the same molecule, but not. The early development phase of pharmaceutical research looks at isomers and other close analogs. Small differences in structure can have large pharmaceutical effects. Indeed, it appears from anecdotal evidence that D-8 is roughly 3 times less potent than D-9.
Above are some of the stable double bond isomers of THC
The other minor isomers, D-10 and Exo, are not particularly stable, so we’ll not discuss them here.
There are of course multiple other isomers and analogs that I won’t trouble you with, so let’s move on to metabolites.
A metabolite is a compound that has been transformed by the liver into a form that is more easily removed from the body. Usually this entails adding an oxygen and hydrogen to a convenient place on the molecule: this make the molecule more water soluble, which helps in removing it from the body. The key metabolites of THC and CBD are hydroxylated at C11 to give the following molecules:
CBD and THC metabolites
Both of these metabolites are biologically active, and produce similar effects as the parent molecules. BUT this is the main difference between smoking/sublingual administration and oral ingestion: eating cannabinoids gives predominately the metabolites in the bloodstream, while smoking gives the parent molecules. This is why the edible experience is so much different from smoking cannabis.