Iso-LSD
Iso-LSD, also known as d-iso-LSD, -iso-LSD, or -LSD, as well as N,''N-diethylisolysergamide, is a serotonin receptor modulator of the lysergamide family related to lysergic acid diethylamide. It is the 8-position epimer of LSD, with iso-LSD being 8α and LSD being 8β. Iso-LSD is also the N'',N-diethyl derivative of isoergine, a constituent found in morning glory seeds. Iso-LSD is one of four possible stereoisomers of LSD.
Use and effects
According to Albert Hofmann and colleagues, iso-LSD is inactive as a psychedelic in humans at doses of up to 500μg, which is up to 25times the minimum given doses of LSD. In other sources, iso-LSD was also stated as being inactive at doses of up to 50μg/kg, whereas LSD is active at a dose of 1μg/kg. Hence, iso-LSD is inactive in humans at doses of up to 50times those of a common psychedelic dose of LSD and at doses of up to 175times the minimum dose of LSD. Alexander Shulgin has additionally reported that iso-LSD was inactive at a dose of 4mg orally. The related drug isoergine is known to be active in terms of psychoactive and hallucinogenic effects at doses of 2 to 5mg orally.Pharmacology
Pharmacodynamics
Iso-LSD shows significant affinity for serotonin receptors. It had an affinity of about 200nM for serotonin receptors in rat brain membranes. For comparison, LSD had an affinity of about 8 to 10nM in the studies, while isoergine had an affinity of 100 to 200nM and ergine had an affinity of about 200nM. Hence, iso-LSD showed about 10- to 30-fold lower affinity for serotonin receptors than LSD but had similar affinity for the receptors as ergine and isoergine. Despite these findings however, iso-LSD showed only 0.12% of the antiserotonergic activity of LSD in the isolated rat uterus.In studies by David E. Nichols and colleagues, iso-LSD fully substituted for LSD in rodent drug discrimination tests. Full substitution occurred at a dose of 0.32mg/kg and its was 0.14mg/kg, whereas the LSD training dose was 0.08mg/kg. Iso-LSD was about 7-fold less potent than LSD in terms of in this assay. In other studies, the drug had about 3.7% of the toxic potency of LSD in rabbits and, unlike LSD, was not pyretogenic.
Pharmacokinetics
Iso-LSD is said to have identical metabolism to LSD. It has a longer elimination half-life than LSD. Iso-LSD's half-life was 12hours while LSD's half-life was 4.2hours.Chemistry
The LSD molecule has two chiral centers at carbons 5 and 8 of the ergoline ring system and hence there are four possible enantiomeric stereoisomers of LSD. Iso-LSD, also known as d-iso-LSD, -iso-LSD, or -LSD, is one of four possible stereoisomers. The other isomers are LSD -LSD, or, l-iso-LSD -iso-LSD or, and l-LSD -LSD or. None of them are known to have significant psychoactivity in humans besides LSD.LSD is easily epimerized into iso-LSD with base. Consequently, iso-LSD is a common synthetic contaminant in chemical synthesis of LSD. Iso-LSD can be easily epimerized back into LSD. LSD can degrade into iso-LSD depending on temperature, solvent and pH, among other factors. In clinical studies, up to 30% of LSD administered in capsules has been found to isomerize into iso-LSD.
Iso-LSD is said to be a metabolite of LSD in animals and humans. However, according to other sources, iso-LSD not a metabolite of LSD but is instead only a contaminant.