Medium: 0.5% sodium lauryl sulfate; 900 mL.

Apparatus 2: 50 rpm.

Time: 45 minutes.

Sodium lauryl sulfate stock solution— Transfer 180.0 g of sodium lauryl sulfate to a 2000-mL volumetric flask. Add 1500 mL of water, and stir until dissolved. [NOTE—Several hours of stirring are required.] Dilute with water to volume.

Standard stock solution— Dissolve about 70 mg of USP Medroxyprogesterone Acetate RS, accurately weighed, in 140 mL of Sodium lauryl sulfate stock solution, and dilute with water to 250 mL. [NOTE—It may be necessary to sonicate the solution to bring the Reference Standard into solution prior to dilution with water. Prepare this Standard stock solution fresh daily.]

Standard solution— Pipet a 20-mL aliquot of Standard stock solution into a 1 L volumetric flask. Add 40 mL of Sodium lauryl sulfate stock solution, and dilute with water to volume. This solution is stable for up to 7 days.

Test solution— Withdraw 15 mL of the solution under test, and filter, discarding the first 5 mL of the filtrate.

Mobile phase— Prepare a filtered and degassed solution of acetonitrile and water (60:40). Make adjustments if necessary (see System Suitability under Chromatography 621).

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 8-cm column that contains packing L7. The flow rate is about 1.5 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the tailing factor for the analyte peak is not more than 1.2; and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of C24H34O4 dissolved from the peak responses so obtained.

Tolerances— Not less than 50% (Q) of the labeled amount of C24H34O4 is dissolved in 45 minutes.

Procedure for content uniformity— Dissolve an accurately weighed portion of USP Medroxyprogesterone Acetate RS in a mixture of alcohol and water (3:1) to obtain a solution having a known concentration of about 15 µg per mL. Transfer 1 Tablet to a volumetric flask, add a mixture of alcohol and water (3:1) to volume, and shake for about 15 minutes. Filter, and quantitatively dilute a portion of the filtrate as required to obtain a final solution containing about 15 µg per mL. Concomitantly determine the absorbances of this solution and the Standard solution in 1-cm cells at the wavelength of maximum absorbance at about 242 nm. Calculate the quantity, in mg, of C24H34O4 in the Tablet taken by the formula: in which T is the labeled quantity, in mg, of medroxyprogesterone acetate in the Tablet; D is the concentration, in µg per mL, of medroxyprogesterone acetate in the solution from the Tablet; C is the concentration, in µg per mL; of USP Medroxyprogesterone Acetate RS in the Standard solution, and AU and AS are the absorbances of the solution from the Tablet and the Standard solution, respectively.

(Official January 1, 2007)

Mobile phase, Standard preparation, and Chromatographic system— Prepare as directed in the Assay under Medroxyprogesterone Acetate.

Assay preparation— Weigh and finely powder not fewer than 20 Tablets. Weigh accurately a portion of the powder, equivalent to about 25 mg of medroxyprogesterone acetate, into a 50-mL glass centrifuge tube. Pipet 25 mL of acetonitrile into the tube, shake to wet the powder thoroughly, and sonicate for not less than 10 minutes, and centrifuge. Use the clear supernatant as the Assay preparation.

Procedure— Proceed as directed for Procedure in the Assay under Medroxyprogesterone Acetate. Calculate the quantity, in mg, of medroxyprogesterone acetate (C24H34O4) in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Medroxyprogesterone Acetate RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.