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.
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.