Neostigmine 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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C₁₂H₁₉BrN₂O₂            303.20

Benzenaminium, 3-[[(dimethylamino) carbonyl)oxy]-N,N,N-trimethyl-, bromide.

(m-Hydroxyphenyl)trimethylammonium bromide dimethylcarbamate CAS RN^®: 114-80-7; UNII: 005SYP50G5.

>> Neostigmine Bromide contains not less than 98.0 percent and not more than 102.0 percent of C₁₂H₁₉BrN₂O₂ calculated on the dried basis.

Packaging and storage-Preserve in tight containers.

1 USP REFERENCE STANDARDS (11)-

USP Neostigmine Bromide RS

1.1 Identification-

Change to read:

A:^▲Spectroscopic Identification Tests (197). Infrared Spectroscopy: 197K _{▲(CN 1-May-2020)}

B: A solution (1 in 50) responds to the tests for Bromide (191).

MELTING RANGE (741): between 171° and 176°, with decomposition.

LOSS ON DRYING (731)-Dry it at 105° for 3 hours: it loses not more than 2.0% of its weight.

RESIDUE ON IGNITION (281): not more than 0.15%.

1.2 Sulfate-

Dissolve 250 mg in 10 mL of water, and add 1 mL of 3 N hydrochloric acid and 1 mL of barium chloride TS: no turbidity is produced immediately.

1.3 Assay-

Dissolve about 750 mg of Neostigmine Bromide, accurately weighed, in a mixture of 70 mL of glacial acetic acid and 20 mL of mercuric acetate TS, add 4 drops of crystal violet TS, and titrate with 0.1 N perchloric acid VS to a blue endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 30.32 mg of C₁₂H₁₉BrN₂O₂,