Conjugated Estrogens Tablets
»Conjugated Estrogens Tablets contain not less than 73.0percent and not more than 95.0percent of the labeled amount of conjugated estrogens as the total of sodium estrone sulfate and sodium equilin sulfate.The ratio of sodium equilin sulfate to sodium estrone sulfate in the Tablets is not less than 0.35and not more than 0.65.
Packaging and storage— Preserve in well-closed containers.
Labeling— The labeling indicates the Tablet strength and states with which in vitro Drug Release Testthe product complies.
Identification— Tablets respond to the Identificationtests under Conjugated Estrogens.
Change to read:
Drug release á724ñ— Proceed as directed for Extended-Release Articles—General Drug Release Standard.
TEST1 (for products labeled as 0.3-,0.45-,USP28and 0.625-mg tablets)—If the product complies with this test,the labeling indicates that it meets USPDrug Release Test 1.
Medium: water;900mL.
Apparatus 2: 50rpm.
Mobile phase— Prepare a filtered and degassed mixture of 0.025Mmonobasic potassium phosphate and acetonitrile (3:1).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard solution— Transfer 10Tablets to a 1000-mLvolumetric flask,dilute with water to volume,and stir vigorously by mechanical means for at least 3hours.Pipet a filtered 100-mLaliquot of the solution into a 900-mLvolumetric flask,and dilute with water to volume.
Test solution— Filter a portion of the solution under test.[NOTE—It is recommended that the filters selected be tested for binding affinity.]
Chromatographic system— The liquid chromatograph is equipped with a 205-nm detector and a 4.6-mm ×3.0-cm column that contains 3-µm packing L1.The flow rate is about 1.5mLper minute.Chromatograph replicate injections of the Standard solution,and record the responses as directed for Procedure:the relative retention times are about 0.9for equilin sulfate and 1.0for estrone sulfate,the estrone sulfate peak being the last major peak in the chromatogram;the resolution,R,between equilin sulfate and estrone sulfate is not less than 1.5;and the relative standard deviation for the estrone sulfate peak is not more than 1.5%.[NOTE—If estrone is present it may be retained on the column for a period longer than 50minutes and interfere in later chromatographic runs.]
Procedure— Separately inject equal volumes (between 20and 200µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the responses for the estrone sulfate peaks.Calculate the percentage of estrone sodium sulfate released by the formula:
100(rU/rS),
in which rUand rSare the peak responses obtained from the Test solutionand the Standard solution,respectively.
Timesand tolerances— The percentages of estrone sodium sulfate dissolved at the times specified conform to Acceptance Table 1.
Time (hours) Amount dissolved
2 between 19%and 49%
5 between 66%and 96%
8 not less than 80%
TEST2 (for products labeled as 0.9-mg tablets)—If the product complies with this test,the labeling indicates that it meets USPDrug Release Test 2.
Medium,Apparatus,Mobile phase,Standard solution,Test solution,Chromatographic system,and Procedure— Proceed as directed for Test 1.
Timesand tolerances— The percentages of estrone sodium sulfate dissolved at the times specified conform to Acceptance Table 1.
Time (hours) Amount dissolved
2 between 12%and 37%
5 between 57%and 85%
8 not less than 80%
TEST3 (for products labeled as 1.25-and 2.50-mg tablets)—If the product complies with this test,the labeling indicates that it meets USPDrug Release Test 3.
Medium,Apparatus,Mobile phase,Standard solution,Test solution,Chromatographic system,and Procedure— Proceed as directed for Test 1.
Timesand tolerances— The percentages of estrone sodium sulfate dissolved at the times specified conform to Acceptance Table 1.
Time (hours) Amount dissolved
2 between 3%and 22%
5 between 37%and 67%
8 between 66%and 96%
12 not less than 80%
Uniformity of dosage units— Assay 10individual Tablets as directed in the Assay,and calculate the average content of conjugated estrogens,as the average of the total contents of sodium estrone sulfate and sodium equilin sulfate,in the 10Tablets.The requirements are met if the content of each of the Tablets is not less than 85.0%and not more than 115.0%of the average content of conjugated estrogens.If the content of not more than 2Tablets falls outside the range of 85.0%to 115.0%of the average content but not outside the range of 75.0%to 125.0%,assay an additional 20Tablets.The requirements are met if the content of not more than 2of the 30Tablets falls outside the limits of 85.0%and 115.0%of that average,and no unit is outside the range of 75.0%to 125.0%of the average content.
Assay—
Internal standard solution,Stock solution,pH5.2Acetate buffer,System suitability solution,Standard preparation,and Chromatographic system— Proceed as directed in the Assayunder Conjugated Estrogens.
Assay preparation— If the Tablets are sugar-coated,carefully remove the color and sugar coatings with water,leaving the shellac coating intact,and dry under nitrogen.Weigh and finely powder not fewer than 20of the Tablets.Transfer an accurately weighed quantity of the powder,equivalent to about 2mg of total conjugated estrogens,to a 50-mLcentrifuge tube fitted with a polytef-lined screw-cap and containing 15mLof pH5.2Acetate bufferand 1g of barium chloride.Proceed as directed in the Assay preparationunder Conjugated Estrogens,beginning with “Cap the tube tightly.”
Procedure— Separately inject equal volumes (about 1µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Separately calculate the quantities,in mg,of sodium estrone sulfate and sodium equilin sulfate in the portion of Tablets taken by the formula:
0.005(1.381CS)(RU/RS),
in which 1.381is the factor converting free estrogen to the conjugate sodium salt;CSis the concentration,in µg per mL,of USP Estrone RSor USP Equilin RSin the Stock solution;and RUand RSare the ratios of the peak response of the appropriate analyte to that of the internal standard obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 778
Pharmacopeial Forum:Volume No.30(1)Page 101
Phone Number:1-301-816-8139