Esterified Estrogens
»Esterified Estrogens is a mixture of the sodium salts of the sulfate esters of the estrogenic substances,principally estrone.It is a dispersion of the estrogenic substances on a suitable powdered diluent.The content of total esterified estrogens is not less than 90.0percent and not more than 110.0percent of the labeled amount.
Esterified Estrogens contains not less than 75.0percent and not more than 85.0percent of sodium estrone sulfate,and not less than 6.0percent and not more than 15.0percent of sodium equilin sulfate,in such proportion that the total of these two components is not less than 90.0percent,of the labeled amount of esterified estrogens.
Packaging and storage— Preserve in tight containers.
Labeling— Label it to state the content of Esterified Estrogens on a weight-to-weight basis.
Identification— It responds to Identificationtest Aunder Conjugated Estrogens.
Free steroids— Proceed with Esterified Estrogens as directed in the test for Limit of estrone,equilin,and 17a-dihydroequilin (free steroids)under Conjugated Estrogens.The limit is 3.0%of free steroids.
Organic volatile impurities,Method Vá467ñ: meets the requirements.
Solvent— Use dimethyl sulfoxide.
Assay—
Internal standard solution,Stock solution,Acetate buffer,pH5.2,System suitability solution,Standard preparation,andChromatographic system— Proceed as directed in the Assayunder Conjugated Estrogens.
Assay preparation— Using an accurately weighed quantity of Esterified Estrogens,equivalent to about 2mg of total esterified estrogens,proceed as directed for Assay preparationin the Assayunder Conjugated Estrogens.
Procedure— Proceed as directed in the Assayunder Conjugated Estrogens.Calculate the quantity,in mg,of each sodium estrogen sulfate (estrone and equilin)in the portion of Esterified Estrogens taken by the formula:
(0.005)(F)Ci(RU/RS),
in which Fis the factor converting free estrogen to the conjugate sodium salt,the factor being 1.377for estrone and 1.380for equilin;Ciis the concentration,in µg per mL,of USP Estrone RSor USP Equilin RS,as appropriate,in the alcohol solution;and RUand RSare the ratios of the estrone or equilin peak areas to the 3-O-methylestrone peak areas 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 779
Phone Number:1-301-816-8139
Return