Edrophonium Chloride

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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Edrophonium Chloride contains not less than 98.0 percent and not more than 100.5 percent of C₁₀H₁₆ClNO, calculated on the dried basis.

1 Packaging and storage

—Preserve in well-closed containers.

USP Reference standards 〈11〉—

USP Edrophonium Chloride RS

2 Identification—

Change to read:

A: Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K (CN 1-May-2020).

Change to read:

B: Spectroscopic Identification Tests 〈197〉, Ultraviolet-Visible Spectroscopy: 197U (CN 1-May-2020) —

Solution: 50 μg per mL.

Medium: 0.1 N hydrochloric acid.

Absorptivities at 273 nm, calculated on the dried basis, do not differ by more than 2.0%.

C: To 10 mL of a solution (1 in 10) add 1 drop of ferric chloride TS: a violet-blue color is produced.

D: It responds to the tests for Chloride 〈191〉.

Melting range 〈741〉: between 165° and 170°, with decomposition.

pH 〈791〉: between 4.0 and 5.0, in a solution (1 in 10).

Loss on drying 〈731〉—Dry it in a suitable vacuum drying tube, using phosphorus pentoxide as the desiccant, for 3 hours: it loses not more than 0.5% of its weight.

Residue on ignition 〈281〉: not more than 0.1%.

Limit of dimethylaminophenol—Dissolve about 500 mg, accurately weighed, in 5 mL of water in a separator. Add 5 mL of pH 8.0 phosphate buffer (see Buffer Solutions in the section Reagents, Indicators, and Solutions), and shake. Extract with five 20-mL portions of chloroform, pooling the extracts in a 100-mL volumetric flask, and add chloroform to volume. The absorbance of this solution, determined in a 1-cm cell at 252 nm, with a suitable spectrophotometer, is not more than that of a 1 in 200,000 solution of dimethylaminophenol in chloroform, similarly measured (0.1%).

3 Assay

—Transfer about 175 mg of Edrophonium Chloride, accurately weighed, to a suitable flask, and dissolve in about 20 mL of glacial acetic acid. Add 5 mL of mercuric acetate TS, then add 1 drop 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 20.17 mg of C₁₀H₁₆ClNO.