A: Infrared Absorption á197Kñ—If a difference appears,dissolve portions of both the test specimen and the USP Reference Standard in dehydrated alcohol,evaporate the solutions to dryness,and repeat the test on the residues.

B: Ultraviolet Absorption á197Uñ—

Test solution: 10mg per mL,in alcohol.

Solution A— Prepare a filtered and degassed mixture of methanol and water (55:45).

Solution B— Use filtered and degassed methanol.

Mobile phase— Use variable mixtures of Solution Aand Solution Bas directed for Chromatographic system.

Blank solution— Use Solution B.

System suitability solution— Dilute a volume of the Test solutionquantitatively,and stepwise if necessary,with methanol to obtain a solution having a concentration of about 5µg of fluoxymesterone per mL.

Test solution— Prepare a solution of Fluoxymesterone in Solution Bcontaining about 0.5mg per mL.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The column temperature is maintained at 40.The flow rate is 1.0mLper minute.The chromatograph is programmed as follows. Chromatograph the Test solution,and record the peak responses as directed for Procedure:the column efficiency is not less than 15,000theoretical plates.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the signal-to-noise ratio for the fluoxymesterone peak is not less than 100.

Procedure— Separately inject equal volumes (about 5µL)of the Blank solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the areas for any peaks that do not appear in the Blank solutionthat have an area equal to or greater than 0.1%of the fluoxymesterone peak.Calculate the percentage of each impurity in the portion of Fluoxymesterone taken by the formula: in which riis the peak response for each impurity;and rsis the sum of the responses of all the peaks:not more than 1.0%of any individual impurity is found;and not more than 2.0%of total impurities is found.

Solvent— Use dimethyl sulfoxide.

Internal standard solution— Dissolve methylprednisolone in a mixture of chloroform and methanol (95:5)to obtain a solution containing about 200µg per mL.

Mobile phase— Prepare a solution containing butyl chloride,water-saturated butyl chloride,tetrahydrofuran,methanol,and glacial acetic acid (475:475:70:35:30).

Standard preparation— Dissolve an accurately weighed quantity of USP Fluoxymesterone RSin Internal standard solutionto obtain a solution having a known concentration of about 0.25mg per mL.

Assay preparation— Dissolve about 25mg of Fluoxymesterone,accurately weighed,in 100.0mLof Internal standard solutionto obtain a solution having a concentration of about 0.25mg per mL.

Procedure— Inject equal volumes of the Assay preparationand the Standard preparationinto a suitable high-pressure liquid chromatograph (see Chromatography á621ñ)of the general type equipped with a detector for monitoring UVlight at 254nm,equipped with a suitable recorder,and capable of providing column pressure up to about 2000psi.The instrument contains a 4-mm ×30-cm stainless steel column that contains packing L3.In a suitable chromatogram,the resolution,R,between fluoxymesterone and the internal standard is not less than 3.0;and the relative standard deviation of the peak response ratios of four replicate injections of the Standard preparationis not more than 2.0%.Calculate the quantity,in mg,of C20H29FO3in the portion of Fluoxymesterone taken by the formula: in which Cis the concentration,in mg per mL,of USP Fluoxymesterone RSin the Standard preparation;and RUand RSare the peak response ratios of fluoxymesterone to the internal standard obtained from the Assay preparationand the Standard preparation,respectively.