Thioridazine Hydrochloride C21H26N2S2·HCl 407.04
10-[2-(1-Methyl-2-piperidyl)ethyl]-2-(methylthio)phenothiazine monohydrochloride [130-61-0]. »Thioridazine Hydrochloride contains not less than 99.0percent and not more than 101.0percent of C21H26N2S2·HCl,calculated on the dried basis. Packaging and storage— Preserve in tight,light-resistant containers. USP Reference standards á11ñ USP Thioridazine 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 by using low-actinic glassware. Identification— A: Infrared Absorption á197Kñ. B: Asolution (1in 10)responds to the tests for Chloride á191ñ. Melting range á741ñ: between 159and 165,but the range between beginning and end of melting does not exceed 3. pHá791ñ: between 4.2and 5.2,in a solution (1in 100). Loss on drying á731ñ Dry it at 105for 4hours:it loses not more than 0.4%of its weight. Residue on ignition á281ñ: not more than 0.1%. Selenium á291ñ: 0.003%,a 100-mg specimen being used,100mg of magnesium oxide being added to the Test Solution. Chromatographic purity— [NOTE—Conduct this procedure in subdued lighting without delay.] Diluting solution: a mixture of methanol and ammonium hydroxide (49:1). Test solution— Transfer 100mg of Thioridazine Hydrochloride,accurately weighed,to a 5-mLvolumetric flask.Dissolve in and dilute with Diluting solutionto volume,and mix. Standard solutions— Dissolve an accurately weighed quantity of USP Thioridazine Hydrochloride RSin Diluting solution,and dilute quantitatively,and stepwise if necessary,with Diluting solutionto obtain a solution having a known concentration of 20.0mg per mL(Standard solution A).Dilute appropriate portions of this solution quantitatively with Diluting solutionto obtain five Standard solutions Bto Fhaving known concentrations of 0.1,0.067,0.025,0.02and 0.01mg per mL,respectively.The final concentrations of Standard solutions Bto Frepresent 0.5%,0.33%,0.125%,0.1%and 0.05%concentration of Standard solution A,respectively. Application volume: 5µL. Developing solvent system: a mixture of chloroform,isopropyl alcohol,and ammonium hydroxide (74:25:1). Procedure— Apply equal spots of the Test solutionand Standard solutions Ato Fas directed under Ordinary Impurities á466ñ.Examine the plate under short-and long-wavelength UVlight,then spray the plate with Dragendorff's TS,dry the plate with a stream of nitrogen,and then spray with hydrogen peroxide TS:any secondary spot in the Test solutionis not more than 0.5%,and the sum of all secondary spots is not more than 0.5%. Organic volatile impurities,Method IVá467ñ: meets the requirements. Assay— Dissolve about 350mg of Thioridazine Hydrochloride,accurately weighed,in 80mLof a solution of equal parts of glacial acetic acid and acetic anhydride,and titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 40.70mg of C21H26N2S2·HCl. Auxiliary Information— Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist Expert Committee:(PA3)Pharmaceutical Analysis 3 USP28–NF23Page 1916 Phone Number:1-301-816-8330