Naloxazone

Naloxazone is an irreversible μ-opioid receptor antagonist which is selective for the μ₁ receptor subtype.[1] Naloxazone produces very long lasting antagonist effects as it forms a covalent bond to the active site of the mu-opioid receptor,[2] thus making it impossible for the molecule to unbind and blocking the receptor permanently until the receptor is recycled by endocytosis.

Naloxazone

Names
IUPAC name (5α)-17-Allyl-3,14-dihydroxy-4,5-epoxymorphinan-6-one hydrazone
Other names Naloxone- 6-hydrazone
Identifiers
CAS Number	73674-85-8
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL354010
PubChem CID	9576788
SMILES C=CCN1CCC23C4C(=NN)CCC2(C1CC5=C3C(=C(C=C5)O)O4)O
Properties
Chemical formula	C19H23N3O3
Molar mass	341.40422 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

It has been reported that naloxazone is unstable in acidic solution, dimerizing into the more stable and much more potent antagonist naloxonazine.[3] Under conditions in which no naloxonazine formation could be detected, naloxazone did not display irreversible μ opioid receptor binding.[3]

See also

• Chlornaltrexamine, an irreversible mixed agonist-antagonist
• Oxymorphazone, an irreversible μ-opioid full agonist

References

1. Pasternak, G.; Childers; Snyder, S. (1980). "Opiate analgesia: Evidence for mediation by a subpopulation of opiate receptors". Science. 208 (4443): 514–6. Bibcode:1980Sci...208..514P. doi:10.1126/science.6245448. PMID 6245448.
2. Ling, Geoffrey S.F.; Simantov, Ronit; Clark, Janet A.; Pasternak, Gavril W. (1986). "Naloxonazine actions in vivo". European Journal of Pharmacology. 129 (1–2): 33–8. doi:10.1016/0014-2999(86)90333-X. PMID 3021478.
3. Hahn, Elliot F.; Pasternak, Gavril W. (1982). "Naloxonazine, a potent, long-lasting inhibitor of opiate binding sites". Life Sciences. 31 (12–13): 1385–8. doi:10.1016/0024-3205(82)90387-3. PMID 6292633.