Packaging and storage— Preserve in tight containers.

USP Reference standards á11ñ— USP Chlorpheniramine Maleate RS.

Identification— Disperse a portion of powdered Tablets,equivalent to about 25mg of chlorpheniramine maleate,in about 20mLof dilute hydrochloric acid (1in 100).Dissolve about 25mg of USP Chlorpheniramine Maleate RSin 20mLof dilute hydrochloric acid (1in 100).Treat each solution as follows.Render alkaline,to a pHof about 11,with sodium hydroxide solution (1in 10).Extract with two 50-mLportions of solvent hexane,collect the extracts in a beaker,and evaporate to dryness.Prepare a mineral oil dispersion of the residue so obtained and determine the IRabsorption spectrum of the preparation in the region between 2µm and 12µm:the spectrum of the test preparation exhibits maxima only at the same wavelengths as that of the Standard preparation.

Dissolution á711ñ—

Uniformity of dosage units á905ñ: meet the requirements.

Assay— Using a portion of powdered Tablets equivalent to 4mg of chlorpheniramine maleate,proceed as directed underSalts of Organic Nitrogenous Bases á501ñ,but using dilute hydrochloric acid (1in 100)instead of the dilute sulfuric acid (1in 350),and dilute sulfuric acid (1in 70),and using solvent hexane instead of the ether,and diluting 10mLof theAssay preparation with dilute hydrochloric acid (1in 100)to 25.0mLto prepare the solution employed for the determination of the absorbance,AU,at 264nm.For the determination ofAS,prepare a solution containing about 40mg of USP Chlorpheniramine Maleate RS,accurately weighed,in 200.0mLof dilute hydrochloric acid (1in 100),and treat 20.0mLof this solution the same as the solution in dilute hydrochloric acid (1in 100)of the portion of Tablets taken.Calculate the quantity,in mg,of C16H19ClN2·C4H4O4in the portion of Tablets taken by the formula: in whichCis the weight,in mg,of USP Chlorpheniramine Maleate RSin the 20.0-mLportion of theStandard preparation.

Expert Committee:(PA1)Pharmaceutical Analysis 1

USP28–NF23Page 450

Phone Number:1-301-816-8379