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

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

Medium: water; 900 mL.

Apparatus 2: 50 rpm.

Times: 3, 6, and 12 hours.

Procedure— Determine the amounts of C16H19ClN2·C4H4O4 and C9H13NO·HCl dissolved by employing the methods set forth in the Assay for chlorpheniramine maleate and the Assay for phenylpropanolamine hydrochloride.

Tolerances— The percentages of the labeled amounts of C16H19 ClN2·C4H4O4 and C9H13NO·HCl dissolved at the specified times conform to Acceptance Table 1.

Medium: water; 900 mL.

Apparatus 2: 50 rpm.

Times: 3, 6, and 12 hours.

Procedure— Determine the amounts of C16H19ClN2·C4H4O4 and C9H13NO·HCl dissolved by employing the methods set forth in the Assay for chlorpheniramine maleate and the Assay for phenylpropanolamine hydrochloride.

Tolerances— The percentages of the labeled amounts of C16H19 ClN2·C4H4O4 and C9H13NO·HCl dissolved at the specified times conform to Acceptance Table 2.

(Official April 1, 2006)

(Official January 1, 2007)

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

Assay preparation— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 40 mg of chlorpheniramine maleate, to a suitable container, add 100 mL of water and 10 mL of phosphoric acid solution (1 in 20), and heat gently until the powder is fully dispersed. Cool to room temperature, and transfer an accurately measured volume of this solution, equivalent to about 0.8 mg of chlorpheniramine maleate, to a 100-mL volumetric flask. Dilute with water to volume, mix, and filter. Quantitatively dilute a portion of this solution, if necessary, with phosphoric acid solution (1 in 1000) to obtain a solution having a concentration of about 8 µg of chlorpheniramine maleate per mL.

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 Tablets taken by the formula: in which C is the concentration, in µg per mL, of USP Chlorpheniramine Maleate RS in the Standard preparation; and rU and rS are the chlorpheniramine peak responses obtained from the Assay preparation and the Standard preparation, respectively.

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

Standard preparation— Dissolve an accurately weighed quantity of USP Phenylpropanolamine Hydrochloride RS in water to obtain a solution having a known concentration of about 2.5 mg per mL. Transfer 1.0 mL of this solution to a 50-mL volumetric flask, add 5 mL of methanol, dilute with phosphoric acid solution (1 in 1000) to volume, and mix.

System suitability solution— Proceed as directed in the Assay for phenylpropanolamine hydrochloride under Chlorpheniramine Maleate and Phenylpropanolamine Hydrochloride Extended-Release Capsules.

Assay preparation— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed quantity of the powder, equivalent to about 500 mg of phenylpropanolamine hydrochloride, to a suitable container, add 100 mL of water and 10 mL of phosphoric acid solution (1 in 20), and heat gently until the powder is fully dispersed. Cool to room temperature, and transfer an accurately measured volume of the solution, equivalent to about 5 mg of phenylpropanolamine hydrochloride, to a 100-mL volumetric flask. 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 phenylpropanolamine peaks. Calculate the quantity, in mg, of phenylpropanolamine hydrochloride (C9H13NO·HCl) in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Phenylpropanolamine Hydrochloride RS in the Standard preparation; and rU and rS are the phenylpropanolamine peak responses obtained from the Assay preparation and the Standard preparation, respectively.