Chlorpromazine
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C17H19ClN2S 318.86

10H-Phenothiazine-10-propanamine,2-chloro-N,N-dimethyl-.
2-Chloro-10-[3-(dimethylamino)propyl]phenothiazine [50-53-3].
»Chlorpromazine contains not less than 98.0percent and not more than 101.0percent of C17H19ClN2S,calculated on the dried basis.
Packaging and storage— Preserve in tight,light-resistant containers.
USP Reference standards á11ñ— USP Chlorpromazine Hydrochloride RS.
NOTE—Throughout the following procedures,protect test or assay specimens,the Reference Standard,and solutions containing them,by conducting the procedures without delay,under subdued light,or using low-actinic glassware.
Identification—
A: The IRabsorption spectrum of a 1in 100solution in carbon disulfide,in a 1.0-mm cell between 7µm and 15µm,exhibits maxima only at the same wavelengths as that of a solution prepared by dissolving 55mg of USP Chlorpromazine Hydrochloride RSin 3mLof 1Nsodium hydroxide and extracting the resulting solution with 5.0mLof carbon disulfide.
B: The principal spot found in the test for Other alkylated phenothiazinescorresponds in RFto the spot from the Standard solution.
Loss on drying á731ñ— Dry it in vacuum at room temperature for 3hours:it loses not more than 1.0%of its weight.
Other alkylated phenothiazines— Dissolve 45.0mg in 10mLof methanol.Dissolve a suitable quantity of USP Chlorpromazine Hydrochloride RSin methanol to obtain a concentration of 5mg per mL(Standard solution),and dilute it quantitatively and stepwise with methanol to obtain a concentration of 25µg per mL(Diluted standard solution).Apply separately 10µLof each of the three solutions to the starting line of a thin-layer chromatographic plate coated with chromatographic silica gel mixture.Develop the chromatogram,using as the solvent system a freshly prepared mixture of equal volumes of ether and ethyl acetate saturated with ammonium hydroxide,until the solvent front has moved about 10cm from the origin.Remove the plate from the chamber,and air-dry for 20minutes.View under short-wavelength UVlight:the area and intensity of any spot,other than the principal spot,from the solution of Chlorpromazine are not greater than those of the spot from the Diluted standard solution(0.5%).
Organic volatile impurities,Method Vá467ñ: meets the requirements.
Solvent— Use dimethyl sulfoxide.
Assay— Place about 750mg of Chlorpromazine,accurately weighed,in a 250-mLconical flask,and dissolve in 25mLof glacial acetic acid,warming gently on a steam bath to effect solution.Cool,add crystal violet TS,and titrate with 0.1Nperchloric acid VSto a blue endpoint.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 31.89mg of C17H19ClN2S.
Auxiliary Information— Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 454
Phone Number:1-301-816-8330