A:Identification—Organic Nitrogenous Bases á181ñ.

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

Mobile phase— Dissolve 4.8g of monobasic potassium phosphate in 880mLof water in a 2-liter cylinder.Add 720mLof methanol and 400mLof acetonitrile,mix,filter,and degas.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

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

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

Chromatographic system (see Chromatography á621ñ)— 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 1mLper 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 20µL)of the Standard preparationand the Assay preparationinto 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 mLof the Injection taken by the formula: in which Cis the concentration,in mg per mL,of USP Tripelennamine Hydrochloride RSin the Standard preparation;Vis the volume,in mL,of Injection taken to prepare the Assay preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.