Imidazenil

Last updated
Imidazenil
Imidazenil structure.svg
Imidazenil ball-and-stick model.png
Clinical data
ATC code
  • none
Identifiers
  • 6-(2-Bromophenyl)-8-fluoro-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxamide
CAS Number
PubChem CID
ChemSpider
UNII
CompTox Dashboard (EPA)
Chemical and physical data
Formula C18H12BrFN4O
Molar mass 399.223 g·mol−1
3D model (JSmol)
  • Brc4ccccc4C/2=N/Cc1c(ncn1c3c\2cc(F)cc3)C(=O)N
  • InChI=1S/C18H12BrFN4O/c19-13-4-2-1-3-11(13)16-12-7-10(20)5-6-14(12)24-9-23-17(18(21)25)15(24)8-22-16/h1-7,9H,8H2,(H2,21,25) Yes check.svgY
  • Key:OCJHYHKWUWSHEN-UHFFFAOYSA-N Yes check.svgY
   (verify)

Imidazenil [1] is an experimental anxiolytic drug which is derived from the benzodiazepine family, and is most closely related to other imidazobenzodiazepines such as midazolam, flumazenil, and bretazenil.

Contents

Imidazenil is a highly potent benzodiazepine receptor partial agonist [2] with an unusual profile of effects, producing some of the effects associated with normal benzodiazepines such as anticonvulsant and anxiolytic effects, yet without any notable sedative or amnestic [3] effects. In fact, imidazenil blocks the sedative effects of diazepam, yet without lowering the convulsion threshold, [4] and so potentially could be a more flexible antidote than the antagonist flumazenil which is commonly used to treat benzodiazepine overdose at present.

Imidazenil has not yet been developed commercially for use in humans, however it has been suggested as a safe and effective treatment for anxiety, [5] a potent yet non-sedating anticonvulsant which might be particularly useful in the treatment of poisoning with organophosphate nerve agents, [6] [7] and as a novel treatment for schizophrenia. [8]

In rats, imidazenil has been demonstrated to have low tolerance or dependence liability, unlike other benzodiazepine receptor agonist ligands, such as diazepam, bretazenil. [9]

Pharmacodynamics

Imidazenil is selective over the type of GABAA receptor it acts on. It acts as a partial agonist on those with a α1β2γ2S composition and as a full agonist on those with a α5β2γ2S composition. [4] Its action can be compared to that of clobazam, another anxioselective benzodiazepine. Clobazam's active metablite N-desmethylclobazam has lower affinity on receptors with an α1 subunit compared to those with an α2. [10] [11] It is believed that the subjective, ataxic, and sedative properties are mediated via α1-containing receptors, while the anxiolytic effects are mediated via the ones with α2, α3, or α5. [4]

See also

References

  1. US 5317018
  2. Thompson DM, Auta J, Guidotti A, Costa E (June 1995). "Imidazenil, a new anxiolytic and anticonvulsant drug, attenuates a benzodiazepine-induced cognition deficit in monkeys". The Journal of Pharmacology and Experimental Therapeutics. 273 (3): 1307–12. PMID   7791102.
  3. Auta J, Faust WB, Lambert P, Guidotti A, Costa E, Moerschbaecher JM (June 1995). "Comparison of the effects of full and partial allosteric modulators of GABA(A) receptors on complex behavioral processes in monkeys". Behavioural Pharmacology. 6 (4): 323–332. doi:10.1097/00008877-199506000-00003. PMID   11224341. S2CID   24584434.
  4. 1 2 3 Auta J, Costa E, Davis JM, Guidotti A (September 2005). "Imidazenil: an antagonist of the sedative but not the anticonvulsant action of diazepam". Neuropharmacology. 49 (3): 425–9. doi:10.1016/j.neuropharm.2005.04.005. PMID   15964602. S2CID   44619421.
  5. Atack JR (August 2003). "Anxioselective compounds acting at the GABA(A) receptor benzodiazepine binding site". Current Drug Targets. CNS and Neurological Disorders. 2 (4): 213–32. doi:10.2174/1568007033482841. PMID   12871032.
  6. Rump S, Gidynska T, Galecka E, Antkowiak O, Nawrocka M, Kowalczyk M (2000). "Effects of imidazenil, a new benzodiazepine receptor partial agonist, in the treatment of convulsions in organophosphate intoxications". Neurotoxicity Research. 2 (1): 17–22. doi:10.1007/bf03033323. PMID   15545002. S2CID   2066413.
  7. Auta J, Costa E, Davis J, Guidotti A (March 2004). "Imidazenil: a potent and safe protective agent against diisopropyl fluorophosphate toxicity". Neuropharmacology. 46 (3): 397–403. doi:10.1016/j.neuropharm.2003.09.010. PMID   14975695. S2CID   41221807.
  8. Guidotti A, Auta J, Davis JM, Dong E, Grayson DR, Veldic M, et al. (July 2005). "GABAergic dysfunction in schizophrenia: new treatment strategies on the horizon". Psychopharmacology. 180 (2): 191–205. doi:10.1007/s00213-005-2212-8. PMID   15864560. S2CID   25147595.
  9. Auta J, Giusti P, Guidotti A, Costa E (September 1994). "Imidazenil, a partial positive allosteric modulator of GABAA receptors, exhibits low tolerance and dependence liabilities in the rat". J Pharmacol Exp Ther. 270 (3): 1262–9. PMID   7932179.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. Ralvenius WT, Acuña MA, Benke D, Matthey A, Daali Y, Rudolph U, Desmeules J, Zeilhofer HU, Besson M (October 2016). "The clobazam metabolite N-desmethyl clobazam is an α2 preferring benzodiazepine with an improved therapeutic window for antihyperalgesia". Neuropharmacology. 109: 366–375. doi:10.1016/j.neuropharm.2016.07.004. PMC   4981430 . PMID   27392635.
  11. Nakajima H (August 2001). "A pharmacological profile of clobazam (Mystan), a new antiepileptic drug". Nihon Yakurigaku Zasshi. Folia Pharmacologica Japonica. 118 (2): 117–22. doi: 10.1254/fpj.118.117 . PMID   11530681.