Methacholine Chloride
(meth'' a koe' leen klor' ide).
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C8H18ClNO2 195.69

1-Propanaminium, 2-(acetyloxy)-N,N,N-trimethyl-, chloride, (±)-.
(±)-(2-Hydroxypropyl)trimethylammonium chloride acetate [62-51-1].
» Methacholine Chloride, dried at 105 for 4 hours, contains not less than 98.0 percent and not more than 101.0 percent of C8H18ClNO2.
Packaging and storage— Preserve in tight containers.
A: Infrared Absorption 197M.
B: A solution (1 in 50) responds to the tests for Chloride 191.
Loss on drying 731 Dry it at 105 for 4 hours: it loses not more than 1.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Acetylcholine chloride— To 2 mL of a solution (1 in 10) add 3 mL of a solution of sodium perchlorate (1 in 5), shake, and immerse in ice water for 5 minutes: no precipitate is formed.
Assay— Transfer to a conical flask about 400 mg of Methacholine Chloride, previously dried and accurately weighed (because it is very hygroscopic, store the dried material in a vacuum desiccator), dissolve it in 50 mL of glacial acetic acid, add 10 mL of mercuric acetate TS and 1 drop of crystal violet TS, and titrate with 0.1 N perchloric acid VS to a blue-green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 19.57 mg of C8H18ClNO2.
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Monograph Hariram Ramanathan, M.S.
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(SM42010) Monographs - Small Molecules 4
USP35–NF30 Page 3837
Pharmacopeial Forum: Volume No. 34(3) Page 629