Norethindrone Acetate Tablets

» Norethindrone Acetate Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of norethindrone acetate (C22H28O3).

Packaging and storage— Preserve in well-closed containers.

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USP Norethindrone Acetate RS

Identification— It responds to the Identification test under Norethindrone Tablets, USP Norethindrone Acetate RS being used to prepare the Standard preparation.

Dissolution

711

—

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.

Uniformity of dosage units

905

: meet the requirements.

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:

(TC / D)(AU / AS)

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.

Assay— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 20 mg of norethindrone acetate, to a separator, add 10 mL of water, and extract with three 25-mL portions of chloroform, filtering each extract through chloroform-washed cotton. Evaporate the combined chloroform extracts on a steam bath to dryness, reducing the heat as dryness is approached. Dissolve the residue in alcohol, transfer the solution to a 100-mL volumetric flask, dilute with alcohol to volume, and mix. Transfer a 5.0-mL aliquot to a 100-mL volumetric flask, dilute with alcohol to volume, and mix. Concomitantly determine the absorbances of this solution and 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 portion of Tablets taken by the formula:

2C(AU / AS)

in which C is the concentration, in µg per mL, of USP Norethindrone Acetate RS in the Standard solution, and AU and AS are the absorbances of the solution from the Tablets and the Standard solution, respectively.

Auxiliary Information— Please check for your question in the FAQs before contacting USP.

Topic/Question	Contact	Expert Committee
Monograph	Mary S. Waddell Scientific Liaison 1-301-816-8124	(SM42010) Monographs - Small Molecules 4
Reference Standards	RS Technical Services 1-301-816-8129 rstech@usp.org
711	Margareth R.C. Marques, Ph.D. Senior Scientific Liaison 1-301-816-8106	(GCDF2010) General Chapters - Dosage Forms

USP35–NF30 Page 4079