A: Infrared Absorption á197Kñ.

B: Ultraviolet Absorption á197Uñ—

Test solution: 10mg per mL,in dioxane.

Adsorbent: a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.

Test solution— Dissolve an accurately weighed amount of Medroxyprogesterone Acetate in methylene chloride to obtain a solution having a concentration of about 20mg per mL.

Standard solution— Prepare a solution of USP Medroxyprogesterone Acetate RSand USP Medroxyprogesterone Acetate Related Compound A RSin methylene chloride containing 20mg per mLand 0.1mg per mL,respectively.

Application volume: 10µL.

Developing solvent system: a mixture of hexanes,tert-butyl methyl ether,and tetrahydrofuran (45:45:10).

Spray reagent— Prepare a solution of 20g of p-toluenesulfonic acid in 100mLof alcohol.

Procedure— Proceed as directed for Thin-Layer Chromatographyunder Chromatography á621ñ.Develop the chromatogram until the solvent front has moved about 10cm.Allow the plate to air-dry,and develop the chromatogram again until the solvent front has moved about 10cm.Allow the plate to dry at 120for 10minutes.Spray the plate with Spray reagent.Heat the plate for 10minutes at 120,and examine the plate under UVlight at 365nm.Any blue fluorescent spot with an RFvalue higher than that of the principal spot due to medroxyprogesterone acetate in the chromatogram obtained from the Test solutionis not more intense than the corresponding blue fluorescent spot in the chromatogram obtained from the Standard solution:not more than 0.5%is found.

Mobile phase— Prepare a filtered and degassed mixture of acetonitrile and water (3:2).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard solution— Dissolve an accurately weighed quantity of USP Medroxyprogesterone Acetate RSin Mobile phase,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having a known concentration of about 50µg per mL.

System suitability solution— Dissolve suitable quantities of megestrol acetate and USP Medroxyprogesterone Acetate RSin Mobile phaseto obtain a solution containing about 40µg of each per mL.

Test solution— Transfer about 62.5mg of Medroxyprogesterone Acetate,accurately weighed,to a 25-mLvolumetric flask,dissolve in and dilute with Mobile phaseto volume,and mix.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1mLper minute.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the resolution,R,between megestrol acetate and medroxyprogesterone acetate is not less than 1.5.Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 3.0%.

Procedure— Inject a volume (about 20µL)of the Test solutioninto the chromatograph,record the chromatogram,and measure the peak responses.Calculate the percentage of each impurity in the portion of Medroxyprogesterone Acetate taken by the formula: in which Cis the concentration,in mg per mL,of USP Medroxyprogesterone Acetate RSin the Standard solution;Wis the weight,in mg,of Medroxyprogesterone Acetate taken to prepare the Test solution;riis the peak response for each impurity obtained from the Test solution;and rSis the response from the major peak obtained from the Standard solution:not more than 1.0%of any individual impurity is found;and not more than 1.5%of total impurities is found.

Mobile phase— Prepare a filtered and degassed mixture of water and acetonitrile (60:40).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Medroxyprogesterone Acetate RSin acetonitrile to obtain a solution having a known concentration of about 1mg per mL.

Assay preparation— Dissolve about 25mg of Medroxyprogesterone Acetate,accurately weighed,in 25.0mLof acetonitrile,and mix.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4-mm ×30-cm column that contains packing L1.The flow rate is about 2mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the tailing factor is not more than 2;and the relative standard deviation of the peak responses for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C24H34O4in the portion of Medroxyprogesterone Acetate taken by the formula: in which Cis the concentration,in mg per mL,of USP Medroxyprogesterone Acetate RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.