Methylisopropyllysergamide
{{Short description|Chemical compound}}
{{Drugbox
| Watchedfields = changed
| verifiedrevid = 452010274
| image = MIPLSD.svg
| width = 175px
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| ATC_prefix = None
| legal_AU =
| legal_CA =
| legal_DE = NpSG
| legal_UK = PSA
| legal_US = Schedule I (isomer of LSD)
| legal_status = Illegal in France{{cite web|date=20 May 2021|title=Arrêté du 20 mai 2021 modifiant l'arrêté du 22 février 1990 fixant la liste des substances classées comme stupéfiants|url=https://www.legifrance.gouv.fr/jorf/id/JORFTEXT000043523554|website=www.legifrance.gouv.fr|lang=fr}}
| bioavailability =
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| PubChem = 57507938
| CAS_number_Ref = {{cascite|correct|CAS}}
| CAS_number = 100768-08-9
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = AC6WQQ5Y4B
| synonyms = MIPLA; Lysergic acid methylisopropylamide
| IUPAC_name = (8β)-N-Isopropyl-N,6-dimethyl-9,10-didehydroergoline-8-carboxamide
| C=20 | H=25 | N=3 | O=1
| SMILES = C4N(C)C1Cc2c[nH]c(ccc3)c2c3C1=CC4C(=O)N(C)C(C)C
| StdInChI=1S/C20H25N3O/c1-12(2)23(4)20(24)14-8-16-15-6-5-7-17-19(15)13(10-21-17)9-18(16)22(3)11-14/h5-8,10,12,14,18,21H,9,11H2,1-4H3
| StdInChIKey=ROICYBLUWUMJFF-UHFFFAOYSA-N
}}
Methylisopropyllysergamide (MIPLA), also known as lysergic acid methylisopropylamide, is an analogue of LSD that was originally discovered by Albert Hofmann at Sandoz during the original structure-activity research into LSD. It has subsequently been investigated in more detail by the team led by David E. Nichols at Purdue University.
The drug is a structural isomer of LSD, with the alkyl groups on the amide nitrogen having been subjected to a methylene shuffle. MIPLA and its ethylisopropyl homologue EIPLA are the only simple N,N-dialkyl lysergamides that approach the potency of LSD itself, being around 1/3-1/2 the potency of LSD,{{cite journal |vauthors=Huang X, Marona-Lewicka D, Pfaff RC, Nichols DE |title=Drug discrimination and receptor binding studies of N-isopropyl lysergamide derivatives |journal=Pharmacology Biochemistry and Behavior |volume=47 |issue=3 |pages=667–73 |date=March 1994 |pmid=8208787 |doi= 10.1016/0091-3057(94)90172-4|s2cid=16490010 }} while all other dialkyl analogues tested (dimethyl, dipropyl, methylethyl etc.) are only around 1/10 as potent as LSD,{{cite journal | vauthors = Hofmann A | title = Psychotomimetic drugs; chemical and pharmacological aspects | journal = Acta Physiologica et Pharmacologica Neerlandica | volume = 8 | pages = 240–258 | date = June 1959 | pmid = 13852489 | url = https://www.samorini.it/doc1/alt_aut/ek/hofmann-psychotomimetic-drugs.pdf }} although some N-monoalkyl lysergamides such as the sec-butyl and t-butyl derivatives were also found to show an activity profile and potency comparable to LSD,{{ cite patent | country = US | number = 2997470 | status = patent | title = Lysergic Acid Amides | pubdate = 1956-03-05 | gdate = 1961-08-22 | inventor = Pioch RP }} and the mono-isopropyl derivative is only slightly weaker than MIPLA.
Apart from its lower potency, the hallucinogenic effects of MIPLA are similar to those of LSD itself, and the main use for this drug has been in studies of the binding site at the 5-HT2A receptor through which LSD exerts most of its pharmacological effects.{{cite journal | vauthors = Nichols DE | title = LSD and its lysergamide cousins. | journal = The Heffter Review of Psychedelic Research | location = Santa Fe, New Mexico | publisher = Heffter Research Institute | date = 2001 | volume = 2 | pages = 80–7 | url = https://www.thevespiary.org/rhodium/Rhodium/Vespiary/talk/files/5022-chap6c758.pdf }}