Norethindrone Tablets, chemical structure, molecular formula, Reference Standards

Norethindrone Tablets

»Norethindrone Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amount of Norethindrone C20H26O2.

Packaging and storage— Preserve in well-closed containers.

USP Reference standards á11ñ— USP Norethindrone RS.

Identification— Mix a portion of powdered Tablets,equivalent to about 50mg of norethindrone,with 15mLof solvent hexane,and stir occasionally for 15minutes.Centrifuge the mixture,then decant and discard the solvent hexane.Extract the residue with two 10-mLportions of solvent hexane,centrifuging and decanting as before,and discard the solvent hexane.Add 25mLof chloroform to the residue,mix by shaking for 1to 2minutes,and filter.Evaporate the filtrate to about 3mL,add a few mLof solvent hexane to induce crystallization,and evaporate to dryness:the IRabsorption 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 á701ñ: 15minutes,the use of disks being omitted.

Uniformity of dosage units á905ñ: meet the requirements.

Assay—

Isoniazid reagent— Dissolve 1.0g of isoniazid in 1000mLof anhydrous methanol,add 1.3mLof hydrochloric acid,and mix.

Procedure— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 0.7mg of norethindrone,to a 50-mLvolumetric flask,and add anhydrous methanol to volume.Mix,and allow to stand for 10minutes,with occasional mixing.Filter a portion of the mixture to clarify the solution,and transfer 10.0mLof the filtrate to a suitable container.Add 2.0mLof Isoniazid reagent,mix,seal,and allow to stand for 30minutes.This is the Assay preparation.Transfer a second 10.0-mLportion of the filtrate to a suitable container,add 2.0mLof methanol,and mix.This is the Assay blank preparation.Transfer 10.0mLof methanol to a suitable container,add 2.0mLof Isoniazid reagent,mix,seal,and allow to stand for 30minutes.This is the Reagent blank preparation.Prepare a Standard preparationby transferring 10.0mLof a solution of USP Norethindrone RSin methanol having a concentration of about 14µg per mLto a suitable container.Add 2.0mLof Isoniazid reagent,mix,seal,and allow to stand for 30minutes.Concomitantly determine the absorbances of these solutions in 1-cm cells,at about 380nm,with a suitable spectrophotometer,using methanol as the reference for the Assay blank preparation,and using the Reagent blank preparationas the reference for the Assay preparationand the Standard preparation.Calculate the quantity,in mg,of C20H26O2in the portion of Tablets taken by the formula:

0.05C(AU-AB)/AS,

in which Cis the concentration,in µg per mL,of the Standard preparation,and AU,AB,and ASare the absorbances of the Assay preparation,the Assay blank preparation,and the Standard preparation,respectively.

Auxiliary Information— Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist

Expert Committee:(PA1)Pharmaceutical Analysis 1

USP28–NF23Page 1394

Phone Number:1-301-816-8139