A: Infrared Absorption 197K.

B: Ultraviolet Absorption 197U—

Solution: 10 µg per mL.

Medium: 0.01 N methanolic sodium hydroxide.

Test solution: 20 mg per mL, in dioxane.

Standard preparation— Prepare as directed under Single-steroid Assay 511, using USP Oxymetholone RS.

Assay preparation— Weigh accurately about 20 mg of Oxymetholone, previously dried, dissolve 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 benzene and alcohol (98:2), 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 315 nm, with a suitable spectrophotometer, against the blank. [note—Use 0.01 N alcoholic sodium hydroxide, rather than alcohol, to elute the silica gel bands.] Calculate the quantity, in mg, of C21H32O3 in the portion of Oxymetholone taken by the formula: in which C is the concentration, in mg per mL, of USP Oxymetholone RS in the Standard preparation, and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.