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.

A: Infrared Absorption á197Kñ.

B: Asolution (1in 10)responds to the tests for Chloride á191ñ.

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%.