Delete the following:

Add the following:

Medium: 0.0005%(w/v)polysorbate 80;500mL.

Apparatus 2: 75rpm.

Time: 60minutes.

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

Standard solution [Note—Avolume of alcohol not exceeding 2%of the final volume of the solution may be used to aid in dissolving the USP Reference Standards.]—Dissolve an accurately weighed quantity of USP Norgestrel RSand USP Ethinyl Estradiol RSin Dissolution Medium,and dilute quantitatively,and stepwise if necessary,with Dissolution Mediumto obtain a solution having known concentrations similar to those expected in the Test solution.

Test solution— Use a portion of the solution under test filtered through 0.7-µm borosilicate microfiber filter.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 247-nm detector (for norgestrel analysis),and a spectrofluorometric detector (for ethinyl estradiol analysis)with an excitation wavelength of about 285nm and an emission wavelength of 310nm,and a 4.6-mm ×15-cm column that contains packing L7.The flow rate is about 1mLper minute.Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.7for ethinyl estradiol and 1.0for norgestrel;and the relative standard deviation for replicate injections is not more than 3.0%for the ethinyl estradiol and norgestrel peaks.

Procedure— Separately inject equal volumes (about 100µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantities,in mg,of norgestrel (C21H28O2)and ethinyl estradiol (C20H24O2)dissolved by the formula: in which Cis the concentration,in mg per mL,of the appropriate USP Reference Standard in the Standard solution;and rUand rSare the peak responses obtained from the Test solutionand the Standard solution,respectively.

Tolerances— Not less than 75%(Q)of the labeled amount of C21H28O2and C20H24O2is dissolved in 60minutes.USP28

Mobile phase— Prepare a degassed mixture of water,acetonitrile,and methanol (45:35:15).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Norgestrel RSand USP Ethinyl Estradiol RSin Mobile phase,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having known concentrations of about 100µg of norgestrel per mLand 10µg of ethinyl estradiol per mL.

Assay preparation— Transfer an accurately counted number of Tablets,equivalent to about 10mg of norgestrel,to a 200-mLvolumetric flask.Add 100.0mLof Mobile phase,accurately measured,sonicate for 10minutes to disintegrate the Tablets,and shake by mechanical means for 20minutes.Centrifuge the clear portion of the solution at about 2000rpm for 10minutes,and filter the clear supernatant.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 215-nm detector and a 4.6-mm ×15-cm column that contains 5-µm packing L7.The flow rate is about 1mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative retention times are about 1.0for ethinyl estradiol and 1.5for norgestrel;the resolution,R,between the two major peaks is not less than 2.5;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 50µL)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 ethinyl estradiol (C20H24O2)and norgestrel (C21H28O2)in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of the relevant USP Reference Standard in the Standard preparation;and rUand rSare the peak responses for the relevant analyte obtained from the Assay preparationand the Standard preparation,respectively.