Naloxazone

Not to be confused with Naloxone.

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 μ-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 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL354010 Y
ChemSpider	23230642
PubChem CID	9576788
InChI InChI=1S/C19H23N3O3/c1-2-8-22-9-7-18-15-11-3-4-13(23)16(15)25-17(18)12(21-20)5-6-19(18,24)14(22)10-11/h2-4,14,17,23-24H,1,5-10,20H2/b21-12+/t14-,17+,18+,19-/m1/s1 Key: XQQRNWNMEFUSMN-UTWDOOMRSA-N
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). Y verify (what is YN ?) Infobox references

Naloxazone is the hydrazone analog of naloxone. It has been reported that naloxazone is unstable in acidic solution, dimerizing into the more stable and much more potent antagonist naloxonazine via the free NH₂ of the hydrazone to form an azine linkage.^[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