Packaging and storage—
Preserve in well-closed containers.
Identification—
B:
To about 100 mg dissolved in 1 mL of alcohol add 10 drops of
cobaltous chloride TS, and shake the solution for about 2 minutes: a bright green color develops, and a fine precipitate is formed.
Chloride 
221
—
Dissolve 1.0 g in a mixture of 3 mL of 2 N nitric acid and 12 mL of water, and add 1 mL of
silver nitrate TS: the turbidity does not exceed that produced by 50 µL of 0.020 N hydrochloric acid (0.0035%).
Sulfate—
Dissolve about 200 mg in a mixture of 2 mL of 2 N nitric acid and 20 mL of water, and filter if necessary. To one-half of the filtrate add 1 mL of
barium chloride TS: no more turbidity is produced than is present in the remaining portion of the filtrate to which nothing has been added.
Heavy metals, Method I 231—
Dissolve 1.0 g in a mixture of 2 mL of 3 N hydrochloric acid and 10 mL of water, evaporate on a steam bath to dryness, and dissolve the residue in 25 mL of water: the limit is 0.002%.
Assay—
Mobile phase, Standard preparation, Resolution preparation, and Chromatographic system—
Prepare as directed in the
Assay under
Lidocaine Hydrochloride.
Assay preparation—
Dissolve about 85 mg of Lidocaine, accurately weighed, with warming if necessary, in 0.5 mL of 1 N hydrochloric acid in a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Lidocaine Hydrochloride. Calculate the quantity, in mg, of C
14H
22N
2O in the portion of Lidocaine taken by the formula:
50C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Lidocaine RS in the
Standard preparation; and
rU and
rS are the lidocaine peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
;)
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