A: It meets the requirements under Identification—Organic Nitrogenous Bases 181.

B: It responds to Identification test B under Prilocaine Hydrochloride.

Mobile phase— Mix 50 mL of glacial acetic acid and 930 mL of water, and adjust with 1 N sodium hydroxide to a pH of 3.40. Mix about 4 volumes of this solution with 1 volume of acetonitrile, such that the retention time of prilocaine is about 4 to 6 minutes. Filter through a membrane filter (1 µm or finer porosity), and degas. Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard preparation— Dissolve an accurately weighed quantity of USP Prilocaine Hydrochloride RS quantitatively in Mobile phase to obtain a solution having a known concentration of about 4 mg per mL.

Assay preparation— Transfer an accurately measured volume of Injection, equivalent to about 200 mg of prilocaine hydrochloride, to a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.

Resolution preparation— Prepare a solution of procainamide hydrochloride in Mobile phase containing about 900 µg per mL. Mix 2 mL of this solution and 20 mL of Standard preparation.

Chromatographic system (see Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm × 30-cm column that contains packing L1, and is operated at a temperature between 20 and 25 maintained at ±1.0 of the selected temperature. The flow rate is about 1.5 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 1.5%. Chromatograph about 10 µL of the Resolution preparation, and record the peak responses as directed for Procedure: the resolution, R, between the prilocaine and procainamide peaks is not less than 2.0.

Procedure— [note—Use peak areas where peak responses are indicated.] Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the liquid chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C13H20N2O·HCl in each mL of the Injection taken by the formula: in which C is the concentration, in mg per mL, of USP Prilocaine Hydrochloride RS in the Standard preparation, V is the volume, in mL, of Injection taken, and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.