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

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

C: Asolution of it responds to the test for Sulfate á191ñ.

D: Transfer a volume of Oral Solution,equivalent to about 6mg of dexbrompheniramine maleate,to a separatory funnel,add 0.5mLof ammonium hydroxide and 5mLof methylene chloride,shake for 1minute,and allow the layers to separate.Use the clear,lower layer as the test solution.Prepare a Standard solution in methanol containing 1.2mg of USP Dexbrompheniramine Maleate RSand a second Standard solution in methanol containing 9mg of USP Pseudoephedrine Sulfate RSper mL.Separately apply 5µLof the test solution and each 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 ethyl ether,methanol,and ammonium hydroxide (16:3:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Locate the spots on the plate by examination under short-wavelength UVlight:the RFvalues of the two principal spots obtained from the test solution correspond to those obtained from the respective Standard solutions.

Add the following:

For Oral Solution Packaged In Single-Unit Containers: meets the requirements.USP28

Add the following:

For Oral Solution Packaged In Multiple-Unit Containers: meets the requirements.USP28

Mobile phase— Prepare a mixture of water,acetonitrile,methanol,and tetrahydrofuran (55:32:8:5).Transfer 0.1mLof phosphoric acid,followed by 0.433g of sodium lauryl sulfate,to each 100mLof this mixture,and mix.Adjust with ammonium hydroxide to a pHof 3.50±0.05,filter,and degas.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).[NOTE—The pHof the Mobile phase is critical,and may cause differences of 1to 4minutes in the retention times of the internal standard and dexbrompheniramine.]

Internal standard solution— Dissolve an accurately weighed quantity of naphazoline hydrochloride in Mobile phaseto obtain a solution containing 0.5mg per mL.

Dexbrompheniramine standard solution— Dissolve an accurately weighed quantity of USP Dexbrompheniramine Maleate RSin Mobile phaseto obtain a solution having a known concentration of about 6000Jµg per mL,Jbeing the ratio of the labeled amount,in mg,of dexbrompheniramine maleate to the labeled amount,in mg,of pseudoephedrine sulfate per mLof the Oral Solution.

Standard preparation— Transfer about 30mg of USP Pseudoephedrine Sulfate RS,accurately weighed,to a 25-mLvolumetric flask,add 5.0mLeach of Dexbrompheniramine standard solutionand Internal standard solution,dilute with Mobile phaseto volume,and mix to obtain a Standard preparationhaving known concentrations of about 1.2Jmg of USP Dexbrompheniramine Maleate RSper mLand about 1.2mg of USP Pseudoephedrine Sulfate RSper mL.

Assay preparation— Using a “to contain”pipet,transfer an accurately measured volume of Oral Solution,equivalent to about 30mg of pseudoephedrine sulfate,to a 25-mLvolumetric flask.Rinse the pipet with about 5mLof Mobile phase,collecting the rinsing in the volumetric flask.Add 5.0mLof Internal standard solution,dilute with Mobile phaseto volume,and mix.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm ×30-cm column that contains packing L11.The flow rate is about 1.5mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative retention times are about 1.0for pseudoephedrine,1.5for naphazoline,and 2.5for dexbrompheniramine;the resolution,R,between the pseudoephedrine and naphazoline peaks is not less than 3;the resolution,R,between the dexbrompheniramine and naphazoline peaks is not less than 3;and the relative standard deviation for replicate injections 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.Calculate the quantities,in mg per mL,of dexbrompheniramine maleate (C10H15BrN2·C4H4O4)and pseudoephedrine sulfate [(C10H15NO)2·H2SO4]in the portion of Oral Solution taken by the formula: in which Cis the concentration,in mg per mL,of the appropriate USP Reference Standard in the Standard preparation;Vis the volume,in mL,of Oral Solution taken;and RUand RSare the ratios of the peak responses of the corresponding analyte and the internal standard obtained from the Assay preparationand the Standard preparation,respectively.