METHACHOLINE CHLORIDE Property

Melting point:

171-173 °C(lit.)

Density 

1.1028 (rough estimate)

refractive index 

1.5790 (estimate)

storage temp. 

-20°C

solubility 

H₂O: 50 mg/mL, clear, colorless

form 

powder

color 

White to Almost white

PH

3.0～7.0 (50g/l, 25℃)

Water Solubility 

almost transparency

Merck 

14,5940

BRN 

4162373

Stability:

Unstable - moisture sensitive. Incompatible with oxidizing agents.

LogP

-3.957 (est)

CAS DataBase Reference

62-51-1

EPA Substance Registry System

1-Propanaminium, 2-(acetyloxy)-N,N,N-trimethyl-, chloride (62-51-1)

Safety

Hazard Codes 

Xn

Risk Statements 

22-36/37/38

Safety Statements 

26-36

WGK Germany 

3

RTECS 

BR5250000

F 

3-10-21

HS Code 

29239000

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

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

METHACHOLINE CHLORIDE Chemical Properties,Usage,Production

Chemical Properties

colourless to white crystalline powder with a slight

Uses

antihypertensive, antianginal

Uses

Acetyl-β-methylcholine (methacholine), an analog of acetylcholine, is use as a receptor agonist to study processes such as airway hyperresponsiveness associated with asthma.

Definition

ChEBI: Methacholine chloride is a quaternary ammonium salt. It contains a methacholine.

General Description

Methacholine chloride occurs as colorless or white crystalsor as a white crystalline powder. It is odorless or has aslight odor and is very deliquescent. It is freely soluble inwater, alcohol, or chloroform, and its aqueous solution isneutral to litmus and bitter. It is hydrolyzed rapidly in alkalinesolutions. Solutions are relatively stable to heat and willkeep for at least 2 or 3 weeks when refrigerated to delaygrowth of molds.

Biochem/physiol Actions

Metabolically stable analog of acetylcholine; muscarinic agonist. Its ability to constrict airway smooth muscle is used to assess bronchial reactivity in the laboratory and clinically.

Clinical Use

Methacholine, acetyl β-methylcholine, is marketed as the racemic mixture. It is a selective muscarinic agonist with very little activity at nicotinic receptors. Although methacholine chloride is marketed as the racemic mixture, the S-(+)-enantiomer is 240-fold more potent than the R-(–)-isomer at muscarinic receptors. In addition, AChE hydrolyzes S-(+)–methacholine at approximately 54% the rate of acetylcholine, whereas the R-(–)–enantiomer is a weak inhibitor. Methacholine chloride is used via inhalation for the diagnosis of asthma. The resulting bronchospasm may be relieved with bronchodilators. Methacholine chloride is available as a powder that is reconstituted for inhalation.

Purification Methods

It forms white hygroscopic needles from Et2O and is soluble in H2O, EtOH and CHCl3. It decomposes readily in alkaline solutions and slowly in H2O. It should be handled and stored in a dry atmosphere. The bromide is less hygroscopic, and the picrate has m 129.5-131o (from EtOH). [racemate: Annis & Ely Biochem J 53 34 1953, IR of iodide: Hansen Acta Chem Scand 13 155 1959, Beilstein 4 IV 1670.]