Estradiol Valerate Injection
» Estradiol Valerate Injection is a sterile solution of Estradiol Valerate in a suitable vegetable oil. It contains not less than 90.0 percent and not more than 115.0 percent of the labeled amount of C23H32O3.
Packaging and storage— Preserve in single-dose or in multiple-dose, light-resistant containers, preferably of Type I or Type III glass.
USP Reference standards 11
USP Estradiol Valerate RS Click to View Structure
Phenol reagent (Folin-Ciocalteu reagent)—Dissolve 100 g of sodium tungstate (Na2WO4·2H2O) and 25 g of sodium molybdate (Na2MoO4·2H2O) in 700 mL of water, in a 1500-mL flask connected by a standard taper joint to a reflux condenser. Add 50 mL of phosphoric acid and 100 mL of hydrochloric acid, and reflux gently for 10 hours. Cool, and add 150 g of lithium sulfate, 50 mL of water, and 4 to 6 drops of bromine. Boil the mixture without the condenser for 15 minutes to remove the excess bromine, cool, transfer to a 1-liter volumetric flask, dilute with water to volume, and filter: the filtrate is golden yellow in color, and has no greenish tint. Store the filtrate in a tight container in a refrigerator. Dilute 1 volume of the filtrate with 2 volumes of water prior to use as the Phenol reagent.
Procedure— Transfer 0.5 mL of Injection to a separator containing 10 mL of solvent hexane and 10 mL of 80% methanol. Shake the contents for 2 minutes, and allow the phases to separate. Add 1 mL of Phenol reagent and 3 mL of sodium carbonate solution (1 in 5) to 1 mL of the bottom layer, and mix: a blue color develops.
Limit of estradiol— Prepare a solution of estradiol in acetone containing 30.0% of the labeled concentration of the Injection, dilute 1.0 mL with the oil labeled as vehicle for the Injection to 10.0 mL, and mix. Apply 5 µL of Injection at a spot 2.5 cm from the bottom edge of and in the center of one section of a thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel, and apply 5 µL of the estradiol solution at the corresponding point in the other section of the plate. Allow the applications to be absorbed by the layer without air-drying, and proceed as directed in the test for Limit of estradiol under Estradiol Valerate, beginning with “Develop the chromatogram in a solvent system.” (The limit of estradiol is 3.0%.)
Other requirements— It meets the requirements under Injections 1.
Mobile phase, and Chromatographic system— Prepare as directed in the Assay under Estradiol Valerate.
Internal standard solution— Prepare a solution of testosterone benzoate in tetrahydrofuran having a concentration of about 8.0 mg per mL.
Standard preparation— Transfer about 20 mg of USP Estradiol Valerate RS, accurately weighed, to a 25-mL volumetric flask. Add 5.0 mL of the Internal standard solution, dilute with tetrahydrofuran to volume, and mix to obtain a solution having a known concentration of about 0.8 mg of USP Estradiol Valerate RS per mL.
Assay preparation— Using a “to contain” pipet, transfer an accurately measured volume of Injection, equivalent to about 20 mg of estradiol valerate, to a 25-mL volumetric flask. Rinse the pipet with small portions of tetrahydrofuran, collecting the washings in the volumetric flask. Add 5.0 mL of Internal standard solution, dilute with tetrahydrofuran to volume, and mix.
Procedure— Proceed as directed for Procedure in the Assay under Estradiol Valerate. Calculate the quantity, in mg, of C23H32O3 in each mL of the Injection taken by the formula:
25(C / V)(RU / RS)
in which C is the concentration, in mg per mL, of USP Estradiol Valerate RS in the Standard preparation, V is the volume, in mL, of Injection taken, and RU and RS are the peak response ratios obtained from the Assay preparation and the Standard preparation, respectively.
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Topic/Question Contact Expert Committee
Monograph Domenick Vicchio, Ph.D.
Senior Scientific Liaison
(SM42010) Monographs - Small Molecules 4
Reference Standards RS Technical Services
USP35–NF30 Page 3111