(es'' tra dye' ol sip' ee oh nate).
Estra-1,3,5(10)-triene-3,17-diol, (17)-, 17-cyclopentanepropanoate.
Estradiol 17-cyclopentanepropionate [313-06-4].
» Estradiol Cypionate contains not less than 97.0 percent and not more than 103.0 percent of C26H36O3, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers.
USP Reference standards 11
B: Ultraviolet Absorption 197U
Solution: 100 µg per mL.
Absorptivities at 280 nm, calculated on the dried basis, do not differ by more than 3.0%.
Melting range 741: between 149 and 153.
Specific rotation 781S: between +39 and +44.
Test solution: 20 mg per mL, in dioxane.
Loss on drying 731 Dry it at 105 for 4 hours: it loses not more than 1.0% of its weight.
Residue on ignition 281: not more than 0.2%.
Mobile phase Dissolve 0.8 g of ammonium nitrate in 300 mL of water, add 700 mL of acetonitrile, and mix.
Internal standard solution Prepare a solution of testosterone benzoate in tetrahydrofuran containing 2.0 mg per mL.
Standard preparation Accurately weigh about 10 mg of USP Estradiol Cypionate RS, and transfer to a 10-mL volumetric flask. Add Internal standard solution to volume, and shake vigorously to dissolve.
Assay preparation Using 10 mg of Estradiol Cypionate, accurately weighed, proceed as directed under Standard preparation.
Procedure Separately inject 10-µL aliquots of the Assay preparation and the Standard preparation into a suitable high-pressure liquid chromatograph fitted with a 280-nm detector, a 4-mm × 30-cm column containing packing L1 and operated at room temperature. The Mobile phase is maintained at a pressure and flow rate capable of giving the required resolution and a suitable elution time. In a suitable system, the resolution factor R (see Chromatography 621) is not less than 3.0 between the peaks for estradiol cypionate and the internal standard. Five replicate injections of the Standard preparation show a relative standard deviation that is not more than 1.5%. Calculate the quantity, in mg, of C26H36O3 in the portion of Estradiol Cypionate taken by the formula:
10C(RU / RS)in which C is the concentration, in mg per mL, of USP Estradiol Cypionate RS in the Standard preparation; and RU and RS are the ratios of the peak responses of the estradiol cypionate and internal standard peaks obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3107