Estradiol Injectable Suspension
» Estradiol Injectable Suspension is a sterile suspension of Estradiol in Water for Injection. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C18H24O2.
Packaging and storage Preserve in single-dose or in multiple-dose containers, preferably of Type I glass.
USP Reference standards 11
USP Endotoxin RS
Identification Transfer a volume of well-mixed Injectable Suspension, equivalent to about 10 mg of estradiol, to a flask, render it acid to bromophenol blue TS with dilute hydrochloric acid (1 in 12), mix thoroughly, and place in an ice bath for 15 minutes. Filter the acidified suspension with suction through a sintered-glass funnel. Wash the crystals of estradiol so isolated with five successive 5-mL portions of water, and dry the funnel and contents at 105 to constant weight. The estradiol so obtained responds to Identification test A and meets the requirements of the test for Melting range under Estradiol.
Bacterial endotoxins 85 It contains not more than 250.0 USP Endotoxin Units per mg of estradiol.
Uniformity of dosage units 905: meets the requirements.
Other requirements It meets the requirements under Injections 1.
Standard preparation Dissolve a suitable quantity of USP Estradiol RS, accurately weighed, in methanol, and dilute quantitatively, and stepwise if necessary, with methanol to obtain a solution having a known concentration of about 40 µg per mL.
Assay preparation Transfer an accurately measured volume of well-mixed Injectable Suspension, equivalent to about 1 mg of estradiol, to a 100-mL beaker, and add water, if necessary, to obtain a volume of about 5 mL. Add 6 g of purified siliceous earth, mix, and pack the mixture tightly into a 20- × 200-mm chromatographic tube containing in its base a pledget of fine glass wool. Dry-rinse the beaker with about 1 g of purified siliceous earth, add the rinsing to the packed column, and wipe out the beaker with a pledget of glass wool used to top the column. Elute the column with 50 mL of ether that previously has been saturated with water, and collect the eluate in a glass-stoppered, 125-mL conical flask. Evaporate with the aid of gentle heat and a current of air to dryness, add 25.0 mL of methanol to the residue, and mix.
Procedure Transfer 1.0 mL each of the Standard preparation and the Assay preparation to separate glass-stoppered, 16- × 150-mm test tubes, and evaporate with the aid of gentle heat and a current of air to dryness. Using a suitable syringe, add 1.0 mL of iron-phenol TS to each tube and to a third, similar tube to provide the blank. Suspend the tubes in a vigorously boiling water bath, mixing them simultaneously after heating for 5 minutes. Remove the tubes after heating in the water bath for a total of 35 minutes, and immediately cool in an ice-water bath. Remove from the ice bath, add 10.0 mL of dilute sulfuric acid (1 in 3) to each tube, mix to obtain homogeneous solutions, and allow to reach room temperature. Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 520 nm, with a suitable spectrophotometer, against the blank. Calculate the quantity, in mg, of C18H24O2 in each mL of the Injectable Suspension taken by the formula:
(0.025C / V)(AU / AS)in which C is the concentration, in µg per mL, of USP Estradiol RS in the Standard preparation, V is the volume, in mL, of Injectable Suspension taken, and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3104