A: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,both relative to the internal standard,as obtained in the Assay.

B: Remove the contents of 20Capsules,and grind the contents to a fine powder.Dissolve a portion of the powder in a mixture of chloroform and methanol (5:1)to obtain a solution containing 3mg of flutamide per mL.The test solution so obtained responds to the Thin-Layer Chromatographic Identification Test á201ñ,a mixture of chloroform and ethyl acetate (3:1)being used as the developing solvent and 20µLeach of the test solution and the Standard solution being applied to the thin-layer chromatographic plate.

Medium: 2%sodium lauryl sulfate solution;1000mL.

Apparatus 2: 75rpm.

Time: 60minutes.

Procedure— Determine the amount of C11H11F3N2O3dissolved from UVabsorbances at the wavelength of maximum absorbances at the wavelength of maximum absorbance at about 306nm on filtered portions of the solution under test,suitably diluted with Dissolution Medium,in comparison with a Standard solution having a known concentration of USP Flutamide RSin the same Medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C11H11F3N2O3is dissolved in 60minutes.

Mobile phase— Prepare as directed in the Assay.

Standard solution— Prepare as directed in the Assayfor Standard preparation.

Test solution— Use the Assay preparation.

Detector sensitivity solution— Transfer an accurately measured volume of the Standard solutioninto a volumetric flask,and dilute quantitatively,and stepwise if necessary,with a mixture of water and acetonitrile (4:1)to obtain a solution having a known concentration of about 0.2µg per mL.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 240-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The column temperature is maintained at 25±5.The flow rate is about 1.0mLper minute.Chromatograph the Detector sensitivity solution,and record the peak area responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 10%for flutamide.

Procedure— Inject a volume (about 20µL)of the Test solutioninto the chromatograph,record the chromatogram,and measure the peak area responses.Calculate the percentage of each impurity in the portion of Capsules taken by the formula: in which riis the peak area response for each impurity,excluding those where peak area responses are less than those obtained from the Detector sensitivity solution;and rsis the sum of the responses of all the peaks:not more than 0.2%for any impurity having a relative retention time of about 0.45is found;not more than 0.1%of any other impurity is found;and not more than 0.3%of total impurities is found.

Diluent— Prepare a mixture of acetronitrile and water (1:1).

Mobile phase— Prepare a filtered and degassed mixture of water and acetonitrile (55:45).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Flutamide RSin Diluent,and dilute quantitatively,and stepwise if necessary,with Diluentto obtain a solution having a known concentration of about 0.5mg per mL.Transfer 20.0mLof this solution into a 50-mLvolumetric flask,and dilute with water to volume to obtain a final concentration of 0.2mg per mL.

Assay preparation— Remove the contents of not fewer than 20Capsules,and mix.Transfer an accurately weighed portion of the powder,equivalent to 125mg of flutamide,into a 250-mLvolumetric flask.Add 180mLof Diluent.Shake the flask for 15minutes.Dilute with Diluentto volume,and mix.Allow the insoluble material to settle.Transfer 20.0mLof supernatant into a 50-mLvolumetric flask,dilute with water to volume,mix,and pass through a polytef membrane filter having a 0.45-µm porosity.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 240-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The column temperature is maintained at 25±5.The flow rate is about 1.0mLper minute.Chromatograph the Standard preparation,and record the peak area response as directed for Procedure:the tailing factor is not more than 2.0;and the relative standard deviation for replicate injections is not more than 1.5%.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the peak area response for the flutamide peak.Calculate the quantity,in mg,of flutamide (C11H11F3N2O3)in the portion of Capsules taken by the formula: in which Cis the concentration,in mg per mL,of USP Flutamide RSin the Standard preparation;and rUand rSare the peak area responses obtained from the Assay preparationand the Standard preparation,respectively.