A: The retention times of the major peaks in the chromatogram of the Assay preparationcorrespond to those in the chromatogram of the Standard preparation,as obtained in the Assay.

B: Transfer 10mLof Oral Solution to a suitable glass-stoppered tube,add 10mLof ether and 2mLof 1Nsodium hydroxide,shake for 5minutes,and allow the layers to separate.The ether layer is the test solution.Prepare a Standard solution in water of USP Pseudoephedrine Hydrochloride RSand USP Triprolidine Hydrochloride RShaving known concentrations of 6mg per mLand 250µg per mL,respectively.Separately apply 10-µLportions of the test solution and the Standard solution to a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Allow the spots to dry,and develop the chromatogram in a solvent system consisting of a mixture of butyl alcohol,glacial acetic acid,and water (8:2:2)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate,mark the solvent front,allow the solvent to evaporate,and examine the plate under short-wavelength and long-wavelength UVlight:the RFvalues of the principal spots obtained from the test solution correspond to those obtained from the Standard solution.

Mobile phase— Prepare a filtered and degassed mixture of alcohol and 0.40%ammonium acetate solution (17:3).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve accurately weighed quantities of USP Pseudoephedrine Hydrochloride RSand USP Triprolidine Hydrochloride RSin 0.01Nhydrochloric acid,and dilute quantitatively and stepwise with 0.01Nhydrochloric acid to obtain a solution having known concentrations of about 1.2mg of USP Pseudoephedrine Hydrochloride RSper mLand about 0.05mg of anhydrous USP Triprolidine Hydrochloride RSper mL,and filter.

Assay preparation— Transfer an accurately measured volume of Oral Solution,equivalent to about 60mg of pseudoephedrine hydrochloride,to a 50-mLvolumetric flask,dilute with 0.01Nhydrochloric acid to volume,and mix.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains packing L3.The flow rate is about 1.5mLper minute.Chromatograph replicate injections of the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation is not more than 2.0%;and the resolution factor between triprolidine and pseudoephedrine is not less than 2.0.The tailing factor for the triprolidine peak is not more than 2.0,and the pseudoephedrine peak is not more than 2.0.

Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.The relative retention times are about 0.68for pseudoephedrine hydrochloride and 1.0for triprolidine hydrochloride.Calculate the quantity,in mg,of pseudoephedrine hydrochloride (C10H15NO·HCl)in the portion of Oral Solution taken by the formula: in which Cis the concentration,in mg per mL,of USP Pseudoephedrine Hydrochloride RSin the Standard preparation;and rUand rSare the peak responses for pseudoephedrine hydrochloride obtained from the Assay preparationand the Standard preparation,respectively.Calculate the quantity,in mg,of triprolidine hydrochloride (C19H22N2·HCl·H2O)in the portion of Oral Solution taken by the formula: in which 332.88and 314.86are the molecular weights of triprolidine hydrochloride monohydrate and anhydrous triprolidine hydrochloride,respectively;Cis the concentration,in mg per mL,calculated on the anhydrous basis,of USP Triprolidine Hydrochloride RSin the Standard preparation;and rUand rSare the peak responses for triprolidine hydrochloride obtained from the Assay preparationand the Standard preparation,respectively.