A: Identification—Organic Nitrogenous Bases 181.

B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

Mobile phase— Dissolve 4.8 g of monobasic potassium phosphate in 880 mL of water in a 2-liter cylinder. Add 720 mL of methanol and 400 mL of acetonitrile, mix, filter, and degas. Make adjustments if necessary (see System Suitability under Chromatography 621).

Standard preparation— Dissolve an accurately weighed quantity of USP Tripelennamine Hydrochloride RS quantitatively in water to obtain a solution having a known concentration of about 0.02 mg per mL. Protect this solution from light.

Assay preparation— Transfer an accurately measured volume of Injection, equivalent to about 4 mg of tripelennamine hydrochloride, to a 200-mL volumetric flask, dilute with water to volume, and mix.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 254-nm detector, a 3.9-mm × 30-mm guard column that contains packing L1, and a 3.9-mm × 30-cm analytical column that contains packing L1. The flow rate is about 1 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 2.0%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the tripelennamine peaks. Calculate the quantity, in mg, of tripelennamine hydrochloride (C16H21N3·HCl) in each mL of the Injection taken by the formula: in which C is the concentration, in mg per mL, of USP Tripelennamine Hydrochloride RS in the Standard preparation; V is the volume, in mL, of Injection taken to prepare the Assay preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.