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 Phenpropionate 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 (2:1) 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 1 in 50 mixture of sulfuric acid in alcohol and heating 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: 20 mg per mL, in dioxane.

Standard preparation— Prepare as directed under Single-Steroid Assay 511, using USP Nandrolone Phenpropionate RS.

Assay preparation— Weigh accurately about 20 mg of Nandrolone Phenpropionate, previously dried, dissolve it in a sufficient quantity of a mixture of equal volumes of alcohol and chloroform to make 10.0 mL, and mix.

Procedure— Proceed as directed for Procedure under Single-Steroid Assay 511, using a solvent system consisting of a mixture of n-heptane and acetone (3:1), through the fourth sentence of the second paragraph under Procedure. Then centrifuge the tubes for 5 minutes, and determine the absorbances of the supernatants in 1-cm cells at the wavelength of maximum absorbance at about 239 nm, with a suitable spectrophotometer, against the blank. Calculate the quantity, in mg, of C27H34O3 in the portion of Nandrolone Phenpropionate taken by the formula: in which C is the concentration, in mg per mL, of USP Nandrolone Phenpropionate RS in the Standard preparation, and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.