Medium: dilute hydrochloric acid (1 in 100) containing 0.02% of sodium lauryl sulfate; 900 mL.

Apparatus 1: 100 rpm.

Time: 60 minutes.

Procedure— Determine the amount of C22H28O3 dissolved from UV absorbances at the wavelength of maximum absorbance at about 248 nm, measured from a baseline drawn from 350 nm through 310 nm and extending beyond the peak maximum, of filtered portions of the solution under test, suitably diluted with Medium, in comparison with a Standard solution having a known concentration of USP Norethindrone Acetate RS in the same medium. [NOTE—The Standard solution may be prepared by dissolving the Reference Standard in a volume of methanol, not exceeding 0.5% of the final volume of the solution, and diluting quantitatively with Dissolution Medium.]

Tolerances— Not less than 70% (Q) of the labeled amount of C22H28O3 is dissolved in 60 minutes.

Procedure for content uniformity— Transfer 1 finely powdered Tablet to a 100-mL volumetric flask with the aid of about 75 mL of alcohol. Heat the alcohol to boiling, and allow the mixture to remain at a temperature just below the boiling point for about 15 minutes, with occasional swirling. Cool to room temperature, dilute with alcohol to volume, mix, and centrifuge a portion of the contents at about 2000 rpm until the solution becomes clear. Dilute a portion of the supernatant quantitatively and stepwise with alcohol to obtain a solution containing approximately 10 µg of norethindrone acetate per mL. Concomitantly determine the absorbances of this solution and of a Standard solution of USP Norethindrone Acetate RS in alcohol having a known concentration of about 10 µg per mL in 1-cm cells at the wavelength of maximum absorbance at about 240 nm, with a suitable spectrophotometer, using alcohol as the blank. Calculate the quantity, in mg, of C22H28O3 in the Tablet taken by the formula: in which T is the labeled quantity, in mg, of norethindrone acetate in the Tablet, C is the concentration, in µg per mL, of USP Norethindrone Acetate RS in the Standard solution, D is the concentration, in µg per mL, of the solution from the Tablet, based upon the labeled quantity per Tablet and the extent of dilution, and AU and AS are the absorbances of the solution from the Tablet and the Standard solution, respectively.

(Official January 1, 2007)

2C(AU / AS),