Packaging and storage—
Preserve in single-dose or in multiple-dose,light-resistant containers,preferably of Type Ior Type IIIglass.
Identification—
Phenol reagent
(Folin-Ciocalteu reagent)—Dissolve 100g of sodium tungstate (Na2WO4·2H2O)and 25g of sodium molybdate (Na2MoO4·2H2O)in 700mLof water,in a 1500-mLflask connected by a standard taper joint to a reflux condenser.Add 50mLof phosphoric acid and 100mLof hydrochloric acid,and reflux gently for 10hours.Cool,and add 150g of lithium sulfate,50mLof water,and 4to 6drops of bromine.Boil the mixture without the condenser for 15minutes 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 1volume of the filtrate with 2volumes of water prior to use as the Phenol reagent.
Procedure—
Transfer 0.5mLof Injection to a separator containing 10mLof solvent hexane and 10mLof 80%methanol.Shake the contents for 2minutes,and allow the phases to separate.Add 1mLof Phenol reagentand 3mLof sodium carbonate solution (1in 5)to 1mLof 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 1.0mLwith the oil labeled as vehicle for the Injection to 10.0mL,and mix.Apply 5µLof Injection at a spot 2.5cm from the bottom edge of and in the center of one section of a thin-layer chromatographic plate (see
Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel,and apply 5µLof 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 estradiolunder
Estradiol Valerate,beginning with “Develop the chromatogram in a solvent system.”(The limit of estradiol is 3.0%.)
Assay—
Internal standard solution—
Prepare a solution of testosterone benzoate in tetrahydrofuran having a concentration of about 8.0mg per mL.
Standard preparation—
Transfer about 20mg of
USP Estradiol Valerate RS,accurately weighed,to a 25-mLvolumetric flask.Add 5.0mLof the
Internal standard solution,dilute with tetrahydrofuran to volume,and mix to obtain a solution having a known concentration of about 0.8mg of
USP Estradiol Valerate RSper mL.
Assay preparation—
Using a “to contain”pipet,transfer an accurately measured volume of Injection,equivalent to about 20mg of estradiol valerate,to a 25-mLvolumetric flask.Rinse the pipet with small portions of tetrahydrofuran,collecting the washings in the volumetric flask.Add 5.0mLof Internal standard solution,dilute with tetrahydrofuran to volume,and mix.
Procedure—
Proceed as directed for
Procedurein the
Assayunder
Estradiol Valerate.Calculate the quantity,in mg,of C
23H
32O
3in each mLof the Injection taken by the formula:
25(C/V)(RU/RS),
in which
Cis the concentration,in mg per mL,of
USP Estradiol Valerate RSin the
Standard preparation,
Vis the volume,in mL,of Injection taken,and
RUand
RSare the peak response ratios obtained from the
Assay preparationand the
Standard preparation,respectively.