Epinephrine Ophthalmic Solution
» Epinephrine Ophthalmic Solution is a sterile, aqueous solution of Epinephrine prepared with the aid of Hydrochloric Acid. It contains not less than 90.0 percent and not more than 115.0 percent of the labeled amount of C9H13NO3. It contains a suitable antibacterial agent and may contain an anti-oxidant, suitable buffers, and chelating and tonicity-adjusting agents.
Packaging and storage Preserve in tight, light-resistant containers.
Labeling The label indicates that the Ophthalmic Solution is not to be used if its color is pinkish or darker than slightly yellow or if it contains a precipitate.
Color and clarity Using the Ophthalmic Solution as the Test solution, proceed as directed for Color and clarity under Epinephrine Injection.
A: The UV absorption spectrum of the Assay preparation prepared as directed in the Assay exhibits maxima and minima at the same wavelengths as that of a similar solution of USP Epinephrine Bitartrate RS.
B: A solution (1 in 2) is levorotatory.
Sterility 71: meets the requirements.
pH 791: between 2.2 and 4.5.
pH 5.8 Buffer Mix 1 volume of 1 M dibasic potassium phosphate with 9 volumes of 1 M monobasic potassium phosphate. Adjust by the addition of small volumes of either solution to a pH of 5.80 ± 0.05.
Standard preparation Dissolve a suitable quantity of USP Epinephrine Bitartrate RS, accurately weighed, in 0.1 N hydrochloric acid to obtain a solution having a known concentration of about 40 µg of epinephrine per mL.
Assay preparation Transfer an accurately measured volume of Ophthalmic Solution, equivalent to about 20 mg of epinephrine, to a 250-mL beaker containing 2.0 mL of pH 5.8 Buffer. Add 9 g of chromatographic siliceous earth, and mix. Carefully transfer the mixture to a 45- × 2.2-cm chromatographic tube containing a pledget of glass wool at the bottom, and tap the column gently to effect packing. Dry-wash the beaker with about 1 g of chromatographic siliceous earth, add to the column, and plug the top with a pledget of glass wool. Wash the column with 100 mL of water-washed ether, and discard the eluant. Add 10.0 mL of 0.1 N hydrochloric acid to a 125-mL separator, and place the separator under the column. To about 100 mL of water-washed ether add 1 mL of bis(2-ethylhexyl) phosphoric acid, and elute the column with this solution, collecting the eluate in the separator. Extract the epinephrine into the aqueous acid layer, and carefully transfer the aqueous layer to a 500-mL volumetric flask. Shake the ether layer with two 50-mL portions of 0.1 N hydrochloric acid, add the acidic aqueous extracts to the volumetric flask, dilute with 0.1 N hydrochloric acid to volume, and mix.
Procedure Concomitantly determine the absorbances of the Assay preparation and the Standard preparation at the wavelength of maximum absorbance at about 280 nm, with a suitable spectrophotometer, using 0.1 N hydrochloric acid as the blank. Calculate the quantity, in mg, of C9H13NO3 in each mL of the Ophthalmic Solution taken by the formula:
0.5(C / V)(AU / AS)in which C is the concentration, in µg per mL, of epinephrine in the Standard preparation; V is the volume, in mL, of Ophthalmic Solution taken; and AU and AS are the absorbances of the Assay preparation and the Standard preparation, respectively.
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USP32NF27 Page 2263