Chemical substance record

Methacholine

55-92-5C₈H₁₈NO₂160.237 g/mol

Organic/Inorganic Small MoleculeChEBI source record

A quaternary ammonium ion in which the nitrogen is substituted with three methyl groups and a 2-acetoxypropyl group. Parasympathomimetic bronchoconstrictor drug used in clinical diagnosis. — ChEBI

Safety references

Safety documents & references

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Identity & molecular properties

Source-linked values

CAS number	55-92-5	ChEBI ↗
Molecular formula	C₈H₁₈NO₂	ChEBI ↗
Molar mass	160.237 g/mol	ChEBI ↗
Monoisotopic mass	160.13321 Da	ChEBI ↗
Formal charge	1	ChEBI ↗
ChEBI identifier	CHEBI:6804	ChEBI ↗

Cross-source molecular data

PubChem

Molar mass	160.23 g/mol	PubChem ↗
Exact mass	160.133753817 Da	PubChem ↗
Computed XLogP	0.6	PubChem ↗
Topological polar surface area (Å²)	26.3	PubChem ↗
H-bond donors	0	PubChem ↗
H-bond acceptors	2	PubChem ↗
Rotatable bonds	4	PubChem ↗

PubChem computed values are shown separately from the ChEBI record. An exact InChIKey match was used to connect the records. Molecular descriptors do not describe a supplied product’s purity, particle size or performance.

Names & structural identifiers

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Source preferred name

methacholine

IUPAC name

2-acetyloxy-N,N,N-trimethylpropan-1-aminium

InChIKey

NZWOPGCLSHLLPA-UHFFFAOYSA-N

SMILES

CC(=O)OC(C)C[N+](C)(C)C

InChI

InChI=1S/C8H18NO2/c1-7(11-8(2)10)6-9(3,4)5/h7H,6H2,1-5H3/q+1

Names & synonyms

2-acetyloxy-N,N,N-trimethylpropan-1-aminium

Names are supplied by ChEBI. Trade names and related synonyms may describe a broader product context.

Classification & relationships

ChEBI ontology

quaternary ammonium ionChEBI parent class · 35267 ↗acetate esterChEBI parent class · 47622 ↗

ester organic molecular entity

Roles recorded in ChEBI

vasodilator agentcholinergic agonistmuscarinic agonistbronchoconstrictor agentepitopeanti-asthmatic agent

Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.

Mass ↔ amount of substance

Calculated from sourced mass

Amount

Input unit

Equivalent amount

0.00624076 mol

Uses 160.237 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.

Elemental composition

Theoretical mass fractions

C

Carbon · 8 atoms

59.97%

O

Oxygen · 2 atoms

19.97%

H

Hydrogen · 18 atoms

11.32%

N

Nitrogen · 1 atom

8.74%

Calculated theoretical mass fractions from the reported formula and PubChem periodic-table atomic masses. These are not assay or purity results.

Research & patent references

Selected source associations

Methacholine-induced cGMP production is regulated by nitric oxide generation in rabbit submandibular gland cells. ↗Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology · 2002 Aug · PMID 12128066

Soluble guanylyl cyclase is localised in the acinar cells and participates in amylase secretion in rat parotid gland. ↗Archives of oral biology · 2004 Sep · PMID 15275856

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Sources & record history

Checked 27 Sep 2026

Identity, formula, mass, synonyms & ontologyEMBL-EBI ChEBI · CHEBI:6804

Release 255, 9 September 2026. ChEBI three-star (manually annotated) source entry. View original record ↗ · CC BY 4.0

Additional molecular descriptorsNCBI PubChem · CID 1993 · retrieved 2026-09-27

PubCAS formats source data, connects references and computes explicitly labelled conversions. CAS cross-references are supplied by ChEBI; they do not constitute CAS verification or endorsement.

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