Color and clarity
Standard solution
Transfer 2.0 mL of 0.100 N iodine VS to a 500-mL volumetric flask, dilute with water to volume, and mix.
Procedure
Visually examine a portion of the Injection (Test solution) in a suitable clear glass test tube against a white background: it is not pinkish and it contains no precipitate. If any yellow color is observed in the Test solution, concomitantly determine the absorbances of the Test solution and the Standard solution in 1-cm cells with a suitable spectrophotometer set at 460 nm: the absorbance of the Test solution does not exceed that of the Standard solution.
Assay
Mobile phase
To 1 L of 0.05 M monobasic sodium phosphate add about 519 mg of sodium 1-octanesulfonate and about 45 mg of edetate disodium, and mix. Adjust by the dropwise addition of phosphoric acid, if necessary, to a pH of 3.8. Mix 85 volumes of this solution with 15 volumes of methanol. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation
Dissolve an accurately weighed quantity of
USP Epinephrine Bitartrate RS in
Mobile phase, and dilute quantitatively, and stepwise if necessary, with
Mobile phase to obtain a solution having a known concentration of about 0.1 mg of epinephrine per mL.
Assay preparation
Transfer an accurately measured volume of Injection, equivalent to about 1 mg of epinephrine, to a 10-mL volumetric flask, dilute with Mobile phase to volume, and mix.
System suitability preparation
Dissolve 10 mg of dopamine hydrochloride in 100 mL of the Standard preparation, and mix.
Chromatographic system (see Chromatography 621)
The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm × 15-cm column that contains packing L7. The flow rate is about 2 mL per minute. Chromatograph the
Standard preparation and the
System suitability preparation, and record the peak responses as directed for
Procedure: the relative retention times are about 1.0 for epinephrine and 2.0 for dopamine hydrochloride; the resolution,
R, between epinephrine and dopamine hydrochloride is not less than 3.5; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 20 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of epinephrine (C
9H
13NO
3) in each mL of the Injection taken by the formula:
(183.20/333.29)(10)(C/V)(rU / rS)
in which 183.20 and 333.29 are the molecular weights of epinephrine and epinephrine bitartrate, respectively;
C is the concentration, in mg per mL, of
USP Epinephrine Bitartrate RS in the
Standard preparation; V is the volume, in mL, of Injection taken; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.