Ethynodiol Diacetate and Mestranol Tablets
»Ethynodiol Diacetate and Mestranol Tablets contain not less than 90.0percent and not more than 110.0percent of the labeled amounts of ethynodiol diacetate (C24H32O4)and mestranol (C21H26O2).
Packaging and storage— Preserve in well-closed containers.
Identification— Place a quantity of finely powdered Tablets,equivalent to about 10mg of ethynodiol diacetate,in a stoppered,15-mLcentrifuge tube.Add 10mLof acetonitrile,insert the stopper in the tube,and mix by shaking and inversion for about 2minutes.Centrifuge at about 1200rpm for 10minutes,and decant the supernatant through filter paper into a suitable container.Evaporate a 5-mLaliquot of the filtrate on a steam bath with the aid of a stream of nitrogen,and dissolve the residue in 1mLof chloroform.Apply 5µLof the solution under test,5µLof a Standard solution of USP Ethynodiol Diacetate RSin chloroform containing 5mg per mL,and 5µLof a Standard solution of USP Mestranol RSin chloroform containing 0.5mg per mLat points about 3cm from one end of a thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Place the plate in a developing chamber containing a mixture of 30volumes of ethyl acetate and 70volumes of cyclohexane to a depth of 2cm,the developing chamber previously having been equilibrated with the solvent mixture as described under Thin-layer Chromatography á621ñ.Remove the plate when the solvent moves to about 15cm above the initial spots,allow it to air-dry at room temperature,spray it with a 1in 2solution of sulfuric acid in water,and heat it at 80for 10minutes:the ethynodiol diacetate spots appear yellowish tan and the mestranol spots appear pink when viewed under white light.The ethynodiol diacetate and mestranol spots from the solution under test have the same relative positions on the plate as the spots from the respective Standard solutions:the RFvalue of ethynodiol diacetate in this system is about 0.8,and the RFvalue of mestranol in this system is about 0.6.
Disintegration á701ñ: 15minutes,the use of disks being omitted.
Uniformity of dosage units á905ñ: meet the requirements for Content Uniformitywith respect to ethynodiol diacetate and to mestranol.
Procedure for content uniformity— Proceed as directed in the Assay,except to reduce by half the concentrations in the Standard preparationand the Assayand to inject twice the volume into the chromatograph.
Assay—
Mobile phase— Prepare a filtered and degassed mixture of methanol,water,and tetrahydrofuran (63:30:7),making adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard preparation— Dissolve accurately weighed quantities of USP Ethynodiol Diacetate RSand USP Mestranol RSin a mixture of methanol and water (4:1)to obtain a solution having a known concentration of about 0.2mg of ethynodiol diacetate per mLand 0.02mg of mestranol per mL.
Assay preparation— Transfer 10Tablets to a glass-stoppered flask,and pipet a sufficient volume of a mixture of methanol and water (4:1)into the flask to obtain a solution having final concentration of approximately 0.2mg of ethynodiol diacetate per mLand 0.02mg of mestranol per mL.Agitate vigorously until the tablets are completely disintegrated.Shake vigorously by mechanical means for 30minutes.Allow the solids to settle for 10minutes,and filter the solution through a 0.5-µm filter.
Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 204-nm detector and a 4.6-mm ×25-cm column that contains packing L13.The flow rate is approximately 1.2mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed under Procedure:the relative retention times are about 0.6for mestranol and 1.0for ethynodiol diacetate.The mestranol is baseline separated from the ethynodiol diacetate peak,and the resolution,R,is not less than 4.0between these two peaks.The relative standard deviation for replicate injections is not more than 2.0%for each analyte.
Procedure— Separately inject equal volumes (about 25µL)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 ethynodiol diacetate (C24H32O4)and mestranol (C21H26O2)per Tablet taken by the formula:
0.1CV(rU/rS),
in which Cis the concentration,in mg per mL,of the appropriate USP Reference Standard in the Standard preparation,Vis the volume,in mL,of the methanol-water solvent added to obtain the Assay preparation,and rUand rSare the peak responses of the corresponding analyte 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 798
Phone Number:1-301-816-8139