Demecarium Bromide

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₃₂H₅₂Br₂N₄O₄ 716.59

Benzenaminium, 3,3′-[1,10-decanediylbis[(methylimino)carbonyloxy]]bis[N,N,N-trimethyl]-, dibromide.

(m-Hydroxyphenyl)trimethylammonium bromide decamethylenebis[methylcarbamate] (2:1)   CAS RN®: 56-94-0; UNII: 61D5V4OKTP.

Demecarium Bromide contains not less than 95.0 percent and not more than 100.5 percent of C₃₂H₅₂Br₂N₄O₄, calculated on the anhydrous basis.

1 Packaging and storage

Preserve in tight, light-resistant containers.

2 USP Reference standards 〈11〉

USP Demecarium Bromide RS

3 Identification

Change to read:

A: Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K

B: Dissolve about 100 mg in 50 mL of 1 N sodium hydroxide, and reflux for 15 minutes. Cool, and add 3 mL of the refluxed solution to 25 mL of saturated sodium bicarbonate solution. Add, with mixing, 4 mL of N,N-dimethyl-p-phenylenediamine dihydrochloride solution (1.5 in 10,000) and 2 mL of sodium hypochlorite solution (1.5 in 20,000): a violet-blue color is produced.

C: Dissolve about 50 mg in 20 mL of water, add 10 mL of a 1 in 50 solution of ammonium reineckate in methanol, and allow to stand for 30 minutes with occasional swirling: a pink reineckate of demecarium forms, and it melts between 131° and 136°, with decomposition.

D: A solution of it responds to the tests for Bromide 〈191〉.

4 pH 〈791〉

between 5.0 and 7.0, in a solution (1 in 100).

5 Water Determination, Method I 〈921〉

not more than 2.0%.

6 Residue on ignition 〈281〉

not more than 0.1%.

7 Limit of m-trimethylammoniophenol bromide

Control solution-Dissolve 100 mg of m-dimethylaminophenol in 10 mL of alcohol in a 1000-mL volumetric flask, dilute with water to volume, and mix. Pipet 1 mL of this solution into a 500-mL volumetric flask, dilute with water to volume, and mix.

Test solution-Transfer 100 mg of Demecarium Bromide to a 100-mL volumetric flask, add water to volume, and mix.

Procedure-Pipet 25 mL of the Test solution into a glass-stoppered, 50-mL centrifuge tube, and pipet 25 mL of the Control solution into a second, similar tube. To each tube add 3 mL of pH 7.0 phosphate buffer (see under Solutions in the section Reagents, Indicators, and Solutions), 1 mL of N,N-dimethyl-p-phenylenediamine dihydrochloride solution (1.5 in 10,000), 5 mL of isobutyl alcohol, and 1 mL of sodium hypochlorite solution (1.5 in 20,000). Insert the stoppers in the tubes, shake the mixtures for 5 minutes, and centrifuge: any blue color produced in the upper layer obtained from the Test solution is not more intense than that obtained from the Control solution.

8 Assay

Dissolve about 0.8 g of Demecarium Bromide, accurately weighed, in a mixture of 75 mL of glacial acetic acid and 15 mL of mercuric acetate TS, warming slightly, if necessary, to effect solution. Add 2 drops of crystal violet TS, and titrate with 0.1 N perchloric acid VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 35.83 mg of C₃₂H₅₂Br₂N₄O₄.