Standard solution— Transfer 2.0mLof 0.100Niodine VSto a 500-mLvolumetric 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 solutionand the Standard solutionin 1-cm cells with a suitable spectrophotometer set at 460nm:the absorbance of the Test solutiondoes not exceed that of the Standard solution.

Mobile phase— To 1liter of 0.05Mmonobasic sodium phosphate add about 519mg of sodium 1-octanesulfonate and about 45mg of edetate disodium,and mix.Adjust by the dropwise addition of phosphoric acid,if necessary,to a pHof 3.8.Mix 85volumes of this solution with 15volumes of methanol.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Epinephrine Bitartrate RSin Mobile phase,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having a known concentration of about 0.1mg of epinephrine per mL.

Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 1mg of epinephrine,to a 10-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.

System suitability preparation— Dissolve 10mg of dopamine hydrochloride in 100mLof the Standard preparation,and mix.

Chromatographic system (see Chromatography á621ñ)—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 2mLper minute.Chromatograph the Standard preparationand the System suitability preparation,and record the peak responses as directed under Procedure:the resolution,R,between the epinephrine and dopamine hydrochloride peaks 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 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.The relative retention times are about 1.0for epinephrine and 2.0for dopamine hydrochloride.Calculate the quantity,in mg,of C9H13NO3in each mLof the Injection taken by the formula: in which 183.20and 333.29are the molecular weights of epinephrine and epinephrine bitartrate,respectively;Cis the concentration,in mg per mL,of USP Epinephrine Bitartrate RSin the Standard preparation;Vis the volume,in mL,of Injection taken;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.