A: The retention time of the chlorpheniramine peak in the chromatogram of the Assay preparationcorresponds to that of the Standard preparationas obtained in the Assay.

B: Transfer the contents of 1Capsule to a 10-mLvolumetric flask,add 5mLof methanol,and insert the stopper into the flask.Sonicate this solution for 10minutes,dilute with water to volume,mix,and filter.Apply separately 10µLof this solution and 10µLof a solution of USP Chlorpheniramine Maleate RSin a mixture of methanol and water (1:1)containing about 1.2mg per mLto 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 acetate,methanol,and ammonium hydroxide (100:5:5)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the chamber,mark the solvent front,allow the solvent to evaporate,and examine the plate under short-wavelength UVlight:the RFvalue of the principal spot observed in the chromatogram of the solution under test corresponds to that obtained from the Standard solution.

Test 1: If the product complies with this test,the labeling indicates that it meets USPDrug Release Test 1.

Medium: water;500mL.

Apparatus 1: 100rpm.

Times: 1.5hours,6.0hours,10.0hours.

Procedure— Determine the amount of C16H19ClN2·C4H4O4dissolved employing the method set forth in the Assay,using a filtered portion of the solution under test in comparison with a Standard solution having a known concentration of USP Chlorpheniramine Maleate RSin the same medium.

Tolerances— The percentages of the labeled amount of C16H19ClN2·C4H4O4dissolved at the times specified conform to Acceptable Table 1.

Test 2: If the product complies with this test,the labeling indicates that it meets USPDrug Release Test 2.Proceed as directed for Method Bunder Delayed-Release (Enteric-Coated)Articles—General Drug Release Standard.

Medium— Prepare as directed under Method B,except use 900mLof media.Operate the apparatus for 1hour in the Acid stageand use the acceptance criteria given under Tolerances.Operate the apparatus for 6hours in the Buffer stage,except to use 900mLof simulated intestinal fluid TSwithout enzyme,and use the acceptance criteria given under Tolerances.

Apparatus 2: 50rpm.

Times: 1.0hour,3.0hours,7.0hours.

Procedure— Proceed as directed in Test 1.

Tolerances— The percentages of the labeled amount of C16H19ClN2·C4H4O4dissolved at the times specified conform to Acceptance Table 1.

Mobile phase— Dissolve 2.0g of sodium perchlorate in 350mLof water.Add 650mLof methanol and 2.0mLof triethylamine,and mix.Filter,and degas this solution prior to use.Make adjustments if necessary (see Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Chlorpheniramine Maleate RSin dilute hydrochloric acid (1in 100)to obtain a solution having a known concentration of about 0.12mg per mL.

Assay preparation— Weigh and mix the contents of not less than 20Capsules.Transfer an accurately weighed portion of the mixture,equivalent to about 120mg of chlorpheniramine maleate,to a 200-mLvolumetric flask.Add about 100mLof dilute hydrochloric acid (1in 100),bring to a boil on a hot plate,and continue boiling moderately for 5minutes.Cool,dilute with dilute hydrochloric acid (1in 100)to volume,mix,and filter.Transfer 10.0mLof the filtrate to a 50-mLvolumetric flask,dilute with dilute hydrochloric acid (1in 100)to volume,and mix.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 261-nm detector and a 3.9-mm ×15-cm column that contains 10-µm packing L1.The flow rate is about 1mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed under Procedure:the column efficiency is not less than 900theoretical plates,the tailing factor is not greater than 2.0,and the relative standard deviation for replicate injections is not more than 1.5%.

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 major peaks.Calculate the quantity,in mg,of C16H19ClN2·C4H4O4in the portion of Capsules taken by the formula: in which Cis the concentration,in mg per mL,of USP Chlorpheniramine Maleate RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.