U.S. PHARMACOPEIA

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Norethindrone Tablets
» Norethindrone Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of norethindrone C20H26O2.
Packaging and storage— Preserve in well-closed containers.
Identification— Mix a portion of powdered Tablets, equivalent to about 50 mg of norethindrone, with 15 mL of solvent hexane, and stir occasionally for 15 minutes. Centrifuge the mixture, then decant and discard the solvent hexane. Extract the residue with two 10-mL portions of solvent hexane, centrifuging and decanting as before, and discard the solvent hexane. Add 25 mL of chloroform to the residue, mix by shaking for 1 to 2 minutes, and filter. Evaporate the filtrate to about 3 mL, add a few mL of solvent hexane to induce crystallization, and evaporate to dryness: the IR absorption spectrum of a potassium bromide dispersion prepared from the residue so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Norethindrone RS.
Disintegration 701: 15 minutes, the use of disks being omitted.
Uniformity of dosage units 905: meet the requirements.
Residual solvents 467: meet the requirements.
(Official January 1, 2007)
Assay—
Isoniazid reagent— Dissolve 1.0 g of isoniazid in 1000 mL of anhydrous methanol, add 1.3 mL of hydrochloric acid, and mix.
Procedure— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 0.7 mg of norethindrone, to a 50-mL volumetric flask, and add anhydrous methanol to volume. Mix, and allow to stand for 10 minutes, with occasional mixing. Filter a portion of the mixture to clarify the solution, and transfer 10.0 mL of the filtrate to a suitable container. Add 2.0 mL of Isoniazid reagent, mix, seal, and allow to stand for 30 minutes. This is the Assay preparation. Transfer a second 10.0-mL portion of the filtrate to a suitable container, add 2.0 mL of methanol, and mix. This is the Assay blank preparation. Transfer 10.0 mL of methanol to a suitable container, add 2.0 mL of Isoniazid reagent, mix, seal, and allow to stand for 30 minutes. This is the Reagent blank preparation. Prepare a Standard preparation by transferring 10.0 mL of a solution of USP Norethindrone RS in methanol having a concentration of about 14 µg per mL to a suitable container. Add 2.0 mL of Isoniazid reagent, mix, seal, and allow to stand for 30 minutes. Concomitantly determine the absorbances of these solutions in 1-cm cells, at about 380 nm, with a suitable spectrophotometer, using methanol as the reference for the Assay blank preparation, and using the Reagent blank preparation as the reference for the Assay preparation and the Standard preparation. Calculate the quantity, in mg, of C20H26O2 in the portion of Tablets taken by the formula:
0.05C(AU AB) / AS,
in which C is the concentration, in µg per mL, of the Standard preparation, and AU, AB, and AS are the absorbances of the Assay preparation, the Assay blank preparation, and the Standard preparation, respectively.
Auxiliary Information— Staff Liaison : Daniel K. Bempong, Ph.D., Scientist
Expert Committee : (MDPS05) Monograph Development-Pulmonary and Steroids
USP29–NF24 Page 1553
Phone Number : 1-301-816-8143