Comment · Tue, February 13, 2018 · Ceretropic & Nootropics Depot
Phenylpiracetam would theoretically metabolize into phenibut, why does nobody ever mention this?
Original post in this thread
Vigu3 · 36 points
From the wikipedia page on oxiracetam
"The major metabolites of Oxiracetam include: beta-hydroxy-2-pyrrolidone, N-aminoacetyl-GABOB, GABOB (beta-hydroxy-GABA) and glycine. Thus its metabolic route is exactly parallel to that of piracetam, aniracetam, phenylpiracetam, and all other members of the -racetam family, and also pyroglutamic acid."
So this implies that most racetams will metabolize by breaking the cyclicized GABA ring (moslty before but partly after the N-substitution is broken off). For example, aniracetam quickly metabolizes to N-anisoyl-GABA, and then GABA, and as mentioned in my reference, Oxiracetam will yield N-aminoacetyl-GABOB, and then GABOB (which is beta-hydroxy-GABA). Additionally, it mentions that other racetams, INCLUDING PHENYLPIRACETAM, will metabolize in the same fashion. With the positioning of the phenyl ring, the first metabolite would be (N-aminoacetyl, beta-phenyl-GABA), and then finally beta-phenyl-GABA, also known as PHENIBUT.
I know for aniracetam, about 70-80% will metabolize to its GABA counterpart, N-anisoyl-GABA.
And this part may be a stretch, but another N-substituted GABA derivative, picamilon, is known to completely hydrolyze into…
What they were answering
Direct reply to the original post — see the thread post above.
u/MisterYouAreSoDumb · Ceretropic & Nootropics Depot
Interesting thought. However, phenylpiracetam is not metabolized in any meaningful amounts, and is excreted mostly unchanged in urine and sweat. Approximately 40% of the dose administered is excreted with urine, and about 60% with bile and transpiration.
Remember, you have to look at a molecule in 3D space, not just as a flat skeletal structure as we are used to. Carbons and hydrogens will fall into a tetrahedral shape, even when in cyclized rings. Then the other chemical groupings will rotate around that structure. So adding in a small change, or a large one like phenylpiracetam-aniracetam, will completely change the shape of the molecule, consequently altering not only the binding affinity, but its ability to be metabolized by enzymes in the body. The bulky phenyl group off the pyrrolidone ring seems to prevent its ability to bind to enzymes that would break that ring.