Standard preparation— Dissolve 25.0mg of USP Nandrolone RSin 50.0mLof acetone.Dilute 5.0mLof this solution with acetone to 50.0mL,and mix.

Test preparation— Transfer an accurately measured volume of Injection,equivalent to about 50mg of nandrolone decanoate,to a 10-mLvolumetric flask,dilute with acetone to volume,and mix.

Procedure— Apply 10µLeach of theStandard preparation and of theTest preparation to a suitable thin-layer chromatographic plate (seeChromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Allow the spots to dry,and develop the chromatogram in a solvent system consisting of a mixture of n-heptane and acetone (3:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Return the dry plate to the developing chamber containing the same solvent system,and again develop the chromatogram until the solvent front has moved the same distance from the origin.Remove the plate from the developing chamber,and allow the solvent to evaporate.Locate the spots on the plate by lightly spraying with a 4in 10solution of sulfuric acid in methanol and heating at about 100for 10minutes.Cool,and examine under long-wavelength UVlight:any yellow fluorescent spot from theTest preparation at anRfvalue of about 0.2is not greater in size or intensity than that produced by theStandard preparation at the sameRfvalue,corresponding to not more than 1.0%of nandrolone.

0.02M Ammonium acetate solution— Transfer about 1.6g of ammonium acetate to a 1-liter volumetric flask.Dissolve in and dilute with water to volume.

Mobile phase— Prepare a filtered and degassed mixture of alcohol and0.02M Ammonium acetate solution (66:34).Make adjustments if necessary (seeSystem Suitability underChromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Nandrolone Decanoate RSwith tetrahydrofuran,and dilute quantitatively and stepwise if necessary,with tetrahydrofuran to obtain a solution having a known concentration of about 0.2mg per mL.

Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 400mg of nandrolone decanoate to a 200-mLvolumetric flask,dilute with tetrahydrofuran to volume,and mix.Transfer 10.0mLof this solution to a 100-mLvolumetric flask,dilute with tetrahydrofuran to volume,and mix.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×15-cm column containing 5-µm packing L1.The flow rate is about 1.5mLper minute.The column temperature is maintained at 40.Chromatograph the Standard preparation,and record the peak responses as directed forProcedure:the capacity factor,k¢,for nandrolone decanoate is not less than 5.3;the tailing factor for the Nandrolone Decanoate peak is not more than 1.4;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 10µL)of theStandard preparation and theAssay preparation into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C28H44O3in each mLof the Injection taken by the formula: in which Cis the concentration,in mg per mL,of USP Nandrolone Decanoate RSin theStandard preparation;Vis the volume,in mL,of the injection taken to prepare theAssay preparation,andrUandrSare the peak responses obtained from theAssay preparation and theStandard preparation,respectively.