Dexchlorpheniramine Maleate
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C16H19ClN2·C4H4O4 390.86

2-Pyridinepropanamine,g-(4-chlorophenyl)-N,N-dimethyl-,(S)-,(Z)-2-butenedioate (1:1).
(+)-2-[p-Chloro-a-[2-(dimethylamino)ethyl]benzyl]pyridine maleate (1:1) [2438-32-6].
»Dexchlorpheniramine Maleate,dried at 65for 4hours,contains not less than 98.0percent and not more than 100.5percent of C16H19ClN2·C4H4O4.
Packaging and storage— Preserve in tight,light-resistant containers.
Identification—
A: Infrared Absorption á197Kñ.
Solution: 40µg per mL.
Medium: water.
Melting range,Class Iá741ñ: between 110and 115.
Specific rotation á781Sñ: between +39.5and +43.0.
Test solution: 50mg per mL,in dimethylformamide.
pHá791ñ: between 4.0and 5.0,in a solution (1in 100).
Loss on drying á731ñ Dry it at 65for 4hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ: not more than 0.2%.
Related compounds—
Test solution— Dissolve about 200mg of Dexchlorpheniramine Maleate in 5mLof methylene chloride,and mix.
Chromatographic system (see Chromatography á621ñ)—The gas chromatograph is equipped with a flame-ionization detector and a 1.2-m ×4-mm glass column containing 3%phase G3on support S1AB.The column temperature is maintained at about 190,and the injection port and detector temperatures are both maintained at about 250.The carrier gas is dry helium,flowing at a rate adjusted to obtain a retention time of 4to 5minutes for the main peak.Chromatograph the Test solution,record the chromatogram,and determine the peak area as directed under Procedure:the tailing factor for the dexchlorpheniramine maleate peak is not more than 1.8.
Procedure— Inject a volume (about 1µL)of the Test solutioninto the chromatograph.Record the chromatogram for a total time of not less than twice the retention time of the dexchlorpheniramine peak,and measure the areas of the peaks.The total relative area of all extraneous peaks (except that of the solvent peak and maleic acid,if observed)does not exceed 2.0%.
Organic volatile impurities,Method Iá467ñ: meets the requirements.
Assay— Dissolve about 400mg of Dexchlorpheniramine Maleate,previously dried and accurately weighed,in 50mLof glacial acetic acid,add 1drop of crystal violet TS,and titrate with 0.1Nperchloric acid VSto a green endpoint.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 19.54mg of C16H19ClN2·C4H4O4.
Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 598
Phone Number:1-301-816-8379