Medium: 0.3%sodium lauryl sulfate;500mL.

Apparatus 2: 100rpm.

Time: 60minutes.

Procedure— Determine the amount of C21H28O2dissolved from UVabsorbances at the wavelength of maximum absorbance at about 295nm of filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Dydrogesterone RSin the same medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C21H28O2is dissolved in 60minutes.

Mobile phase,Standard preparation,System suitability preparation,and Chromatographic system— Proceed as directed in the Assayunder Dydrogesterone.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer a portion of the powder,equivalent to about 20mg of Dydrogesterone,to a 200-mLvolumetric flask,add about 100mLof Mobile phase,and sonicate for 10minutes.Cool to room temperature,dilute with Mobile phaseto volume,and mix.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and determine the peak responses by area measurement.Calculate the quantity,in mg,of C21H28O2in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Dydrogesterone RSin the Standard preparation,and rUand rSare the Dydrogesterone peak area responses from the Assay preparationand the Standard preparation,respectively.