A: Infrared Absorption á197Kñ.

B: Ultraviolet Absorption á197Uñ—

Solution: 10µg per mL.

C: Prepare a solution in acetone containing 5mg per mL.Apply 10µLof this solution and 10µLof a solution of USP Nandrolone Decanoate RSin acetone containing 5mg per mLto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.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.Locate the spots on the plate by lightly spraying with a solution of sulfuric acid in alcohol (1in 50)and heating in an oven at 110for 15minutes:the RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.

Test solution: 10mg per mL,previously dried in dioxane.

Solvent: dimethyl sulfoxide.

Mobile phase— Prepare a filtered and degassed mixture of chromatographic n-heptane and n-propyl alcohol (HPLCgrade)(97:3).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

System suitability solution— Dissolve accurately weighed quantities of USP Nandrolone Decanoate RS,dimethyl phthalate,and USP Nandrolone RSin Mobile phase,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having known concentrations of about 0.25mg per mL,0.25mg per mL,and 0.16mg per mL,respectively.

Test solution— Transfer about 13mg of Nandrolone Decanoate,accurately weighed,to a 50-mLvolumetric flask,dissolve in and dilute with Mobile phaseto volume,and mix.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 238-nm detector and a 4.6-mm ×25-cm column that contains packing L10.The flow rate is about 1mLper minute.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.67for dimethyl phthalate and 1.0for nandrolone decanoate;the resolution,R,between dimethyl phthalate and nandrolone decanoate is not less than 9.0,and the nandrolone peak elutes before 4.5times the elution time of nandrolone decanoate;the tailing factor is not more than 1.3for the nandrolone decanoate and dimethyl phthalate peaks;and the relative standard deviation for replicate injections is not more than 2.0%.

Mobile phase— Prepare a filtered and degassed mixture of methanol and water (95:5).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Transfer an accurately weighed quantity of USP Nandrolone Decanoate RSto a suitable volumetric flask,and dilute with methanol to volume to obtain a solution having a known concentration of about 0.2mg per mL.

Assay preparation— Transfer an accurately weighed quantity of about 20mg of Nandrolone Decanoate to a 100-mLvolumetric flask.Dissolve in and dilute with methanol to volume,and mix.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 240-nm detector and an 8-mm ×10-cm analytical column containing packing L1.The flow rate is about 1.0mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the capacity factor,k¢,is not less than 1.3;the column efficiency is not less than 8000theoretical plates;the tailing factor is not less than 0.9and not more than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparation into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C28H44O3in the portion of Nandrolone Decanoate taken by the formula: in which Cis the concentration,in mg per mL,of USP Nandrolone Decanoate RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.