METHACHOLINE BROMIDE Property

Melting point:

147-149 °C(lit.)

Density 

1.3952 (rough estimate)

refractive index 

1.6120 (estimate)

storage temp. 

-20°C

form 

Crystalline Powder

color 

White to off-white

Water Solubility 

almost transparency

Sensitive 

Hygroscopic

BRN 

6098010

EPA Substance Registry System

1-Propanaminium, 2-(acetyloxy)-N,N,N-trimethyl-, bromide (333-31-3)

Safety

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26-36

WGK Germany 

3

TSCA 

Yes

HS Code 

29239000

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P271Use only outdoors or in a well-ventilated area.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

METHACHOLINE BROMIDE Chemical Properties,Usage,Production

Chemical Properties

WHITE CRYSTALLINE POWDER

Uses

Methacholine is used only for bronchial hyperreactivity diagnostics. A synonym of this drug is provocholine.

Uses

Acetyl-β-methylcholine bromide (methylcholine bromide, methacholine bromide, Mch), a muscarinic acetylcholine receptor agonist, may be used in studies that involve the indentification, characterization and mechanism of action of muscarinic acetylcholine receptors. Mch may be used as a reference material in procedures used to detect or quantify its presence.

General Description

Methacholine can exist as (S) and (R) enantiomers.Although the chemical is used as the racemic mixture, itsmuscarinic activity resides principally in the (S)-isomer.The (S)/(R) ratio of muscarinic potency for these enantiomersis 240:1.

Mechanism of action

A minor structural change is the presence of a methyl group at the β-carbon atom of choline, which results in two main changes in the pharmacological profile of the molecule. Unlike acetylcholine, methacholine is hydrolyzed only by acetylcholinesterase, and the rate of hydrolysis is significantly less than with acetylcholine. Thus, the action of methacholine is significantly longer lasting than acetylcholine. Moreover, the presence of a methyl group at the β-carbon of choline provides the compound with a greater selectivity of action. Methacholine directly acts on muscarinic receptors of smooth muscle, glands,and the heart, and it has a very weak effect on nicotinic receptors of the autonomic ganglions of skeletal muscle.

Synthesis

Methacholine, 1-acetoxy-2-(N,N,N-trimethyl)propyl ammonium chloride (13.1.4) or acetyl-β-methylcholine can be synthesized by any of the methods described above [8]