A: Infrared Absorption 197K.

B: Ultraviolet Absorption 197U—

Solution: 10 µg per mL.

C: Prepare a solution in acetone containing 5 mg per mL. Apply 10 µL of this solution and 10 µL of a solution of USP Nandrolone Decanoate RS in acetone containing 5 mg per mL to a suitable thin-layer chromatographic plate (see Chromatography 621) 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 (1 in 50) and heating in an oven at 110 for 15 minutes: the RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.

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

Mobile phase— Prepare a filtered and degassed mixture of chromatographic n-heptane and n-propyl alcohol (HPLC grade) (97:3). Make adjustments if necessary (see System suitability under Chromatography 621).

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

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

Chromatographic system (see Chromatography 621)—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 1 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.67 for dimethyl phthalate and 1.0 for nandrolone decanoate; the resolution, R, between dimethyl phthalate and nandrolone decanoate is not less than 9.0, and the nandrolone peak elutes before 4.5 times the elution time of nandrolone decanoate; the tailing factor is not more than 1.3 for 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 Suitability under Chromatography 621).

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

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

Chromatographic system (see Chromatography 621)—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 1.0 mL per 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 8000 theoretical plates; the tailing factor is not less than 0.9 and 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 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C28H44O3 in the portion of Nandrolone Decanoate taken by the formula: in which C is the concentration, in mg per mL, of USP Nandrolone Decanoate RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.