» Estradiol Tablets contain not less than 90.0 percent and not more than 115.0 percent of the labeled amount of C18H24O2.
Packaging and storage Preserve in tight, light-resistant containers.
Identification Place a quantity of finely powdered Tablets, equivalent to about 4 mg of estradiol, in a screw-capped, 20-mL vial. Add 10 mL of chloroform, and sonicate for 2 minutes. Filter through medium-porosity filter paper. Apply 20 µL each of this solution and a Standard solution of USP Estradiol RS in chloroform containing 0.4 mg per mL to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a lined chamber with a solvent system consisting of a mixture of toluene and acetone (4:1) until the solvent front has moved 10 cm beyond the starting line. Remove the plate from the developing chamber, mark the solvent front, and allow to air-dry. Spray the plate with a mixture of methanol and sulfuric acid (1:1), and heat at 100 for about 5 minutes: the principal spots obtained from the test solution and the Standard solution have the same color and RF value.
Medium: 0.3% sodium lauryl sulfate in water; 500 mL.
Apparatus 2: 100 rpm.
Time: 60 minutes.
Mobile phase Prepare a suitable degassed and filtered solution of water and acetonitrile (55:45).
Standard solution Prepare a solution of USP Estradiol RS in methanol having an accurately known concentration of about 0.02 mg per mL. Dilute aliquots of this solution with Medium to obtain a final solution having a concentration approximately equal to the expected concentration of drug in the Medium, assuming 100% dissolution.
Test solution Use a filtered portion of the solution under test from the dissolution vessel.
Chromatographic system (see Chromatography 621)The liquid chromatograph is equipped with a 205-nm detector and a 4.6-mm × 7.5-cm column that contains packing L1. The flow rate is about 1.5 mL per minute. Chromatograph replicate injections of the Standard preparation, and record the peak areas as directed for Procedure: the tailing factor is not more than 2.0; and the relative standard deviation is not more than 2.0%.
Procedure Separately inject equal volumes (about 100 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the quantity of C18H24O2 dissolved by comparison of the peak areas obtained from the Test solution and the Standard solution.
Tolerances Not less than 75% (Q) of the labeled amount of C18H24O2 is dissolved in 60 minutes.
Uniformity of dosage units 905: meet the requirements.
Mobile phase, Internal standard solution, Standard preparation, and Chromatographic system Proceed as directed in the Assay under Estradiol.
Assay preparation Weigh and finely powder not fewer than 10 Tablets. Transfer a portion of the powder, equivalent to about 8 mg of estradiol, to a 100-mL volumetric flask. Add 4 mL of water, and swirl. Add 10.0 mL of Internal standard solution and about 60 mL of methanol. Shake by mechanical means for 15 minutes, dilute with methanol to volume, mix, and allow the solids to settle. Filter a portion, discarding the first 10 mL of the filtrate. Mix 5.0 mL of the subsequent filtrate with 5.0 mL of methanol and 10.0 mL of water.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 2304Pharmacopeial Forum: Volume No. 34(3) Page 596
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.