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

B: The retention time of the major peak for pseudoephedrine hydrochloride in the chromatogram of the Assay preparation corresponds to that of the Standard preparation in the Assay for pseudoephedrine hydrochloride.

for oral solution packaged in single-unit containers: meets the requirements.

for oral solution packaged in multiple-unit containers: meets the requirements.

Mobile phase, System suitability solution, and Chromatographic system— Proceed as directed in the Assay for chlorpheniramine maleate under Chlorpheniramine Maleate and Pseudoephedrine Hydrochloride Extended-Release Capsules.

Standard preparation— Dissolve an accurately weighed quantity of USP Chlorpheniramine Maleate RS in water to obtain a solution having a known concentration of about 1 mg per mL. Transfer 1.0 mL of this solution to a 100-mL volumetric flask, add 80 mL of Mobile phase, dilute with water to volume, and mix.

Assay preparation— Transfer an accurately measured volume of Oral Solution, equivalent to about 1 mg of chlorpheniramine maleate, to a 100-mL volumetric flask. Add about 80 mL of Mobile phase, dilute with water to volume, mix, and filter.

Procedure— Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the chlorpheniramine peaks. Calculate the quantity, in mg, of chlorpheniramine maleate (C16H19ClN2·C4H4O4) in the portion of Oral Solution taken by the formula: in which C is the concentration, in mg per mL, of USP Chlorpheniramine Maleate RS in that Standard preparation; V is the volume, in mL, of Oral Solution taken for the Assay preparation; and rU and rS are the chlorpheniramine peak responses obtained from the Assay preparation and the Standard preparation, respectively.

Mobile phase, System suitability solution, and Chromatographic system— Proceed as directed in the Assay for chlorpheniramine maleate under Chlorpheniramine Maleate and Pseudoephedrine Hydrochloride Extended-Release Capsules.

Standard preparation— Dissolve an accurately weighed quantity of USP Pseudoephedrine Hydrochloride RS in water to obtain a solution having a known concentration of about 1.5 mg per mL. Transfer about 1.0 mL of this solution to a 10-mL volumetric flask, add 8 mL of Mobile phase, dilute with water to volume, and mix.

Assay preparation— Transfer an accurately measured volume of Oral Solution, equivalent to about 15 mg of pseudoephedrine hydrochloride, to a 100-mL volumetric flask. Add 80 mL of Mobile phase, dilute with water to volume, mix, and filter.

Procedure— Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the pseudoephedrine peaks. Calculate the quantity, in mg, of pseudoephedrine hydrochloride (C10H15NO·HCl) in the portion of Oral Solution taken by the formula: in which C is the concentration, in mg per mL, of USP Pseudoephedrine Hydrochloride RS in the Standard preparation; V is the volume, in mL, of Oral Solution taken for the Assay preparation; and rU and rS are the pseudoephedrine peak responses obtained from the Assay preparation and the Standard preparation, respectively.