Standard preparation— Prepare as directed in the test for Limit of nandrolone under Nandrolone Decanoate Injection.

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

Procedure— Proceed as directed for Procedure in the test for Limit of nandrolone under Nandrolone Decanoate Injection.

Isoniazid reagent— Dissolve 500 mg of isoniazid in about 250 mL of methanol, add 0.63 mL of hydrochloric acid, dilute with methanol to 500.0 mL, and mix.

Standard preparation— Transfer about 25 mg of USP Nandrolone Phenpropionate RS, accurately weighed, to a 100-mL volumetric flask, dissolve in chloroform, dilute with chloroform to volume, and mix. Transfer 5.0 mL of this solution to a 50-mL volumetric flask, dilute with chloroform to volume, and mix.

Assay preparation— Transfer an accurately measured volume of Injection, equivalent to about 50 mg of nandrolone phenpropionate, to a 200-mL volumetric flask, dilute with chloroform to volume, and mix. Transfer 5.0 mL of this solution to a 50-mL volumetric flask, dilute with chloroform to volume, and mix.

Procedure— Transfer 5.0 mL each of the Standard preparation, of the Assay preparation, and of chloroform to provide the blank, to separate 10-mL volumetric flasks, dilute each flask with Isoniazid reagent to volume, and mix. Allow the flasks to stand for 1 hour with occasional shaking. Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 380 nm, with a suitable spectrophotometer, against the blank. Calculate the quantity, in mg, of C27H34O3 in each mL of the Injection taken by the formula: in which C is the concentration, in µg per mL, of USP Nandrolone Phenpropionate RS in the Standard preparation, V is the volume, in mL, of Injection taken, and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.