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.

A: The UVabsorption spectrum of the solution employed for measurement of absorbance in the Assayexhibits maxima and minima at the same wavelengths as that of a similar solution of USP Trifluoperazine Hydrochloride RS,concomitantly measured.

B: Triturate a portion of powdered Tablets,equivalent to about 10mg of trifluoperazine,with 10mLof methanol,and centrifuge.A5-µLportion of this solution responds to Identificationtest Dunder Trifluoperazine Hydrochloride.

Medium: 0.1Nhydrochloric acid;900mL.

Apparatus 1: 50rpm.

Time: 30minutes.

Procedure— Determine the amount of trifluoperazine (C21H24F3N3S)dissolved from UVabsorbances at the wavelength of maximum absorbance at about 255nm (determine the analytical value to be used for the absorbance at 255nm by subtracting the absorbance at 278nm from the observed maximum absorbance at 255nm),using filtered portions of the solution under test,suitably diluted with 0.1Nhydrochloric acid,in comparison with a Standard solution having a known concentration of USP Trifluoperazine Hydrochloride RSin the same medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C21H24F3N3Sis dissolved in 30minutes.

Mobile phase— To 2.9g of dl-10-camphorsulfonic acid,add 200mLof water and stir until solution is complete.Adjust with 1Nsodium hydroxide to a pHof 3.0,dilute with methanol to 1000mL,mix,and filter through a 0.45-µm membrane filter.

Standard preparation— Dissolve an accurately weighed quantity of USP Trifluoperazine Hydrochloride RSin methanol to obtain a solution having a known concentration of about 12µg of trifluoperazine hydrochloride per mL(10µg of trifluoperazine per mL).

Assay preparation— Weigh and finely powder not less than 20Tablets.Weigh accurately a portion of the powder,equivalent to about 20mg of trifluoperazine,add to a 100-mLvolumetric flask,dilute with methanol to volume,and mix.Transfer 5.0mLof this solution to a second 100-mLvolumetric flask,dilute with methanol to volume,and mix.Filter the solution through a 0.45-µm filter.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 262-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1.5mLper minute.Chromatograph replicate injections of the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 2.0%,and the tailing factor for the trifluoperazine peak is not more than 2.0.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C21H24F3N3S,in the portion of Tablets taken by the formula: in which 407.51and 480.43are the molecular weights of trifluoperazine and trifluoperazine hydrochloride,respectively,Cis the concentration,in mg per mL,of USP Trifluoperazine Hydrochloride RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.