Packaging and storage—
Preserve in tight containers.
Identification—
B:
A solution (1 in 50) responds to the tests for
Bromide 
191
.
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.
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 C
12H
19BrN
2O
2.
;)
for 3 hours: it loses not more than 2.0% of its weight.