Identification
Concentrate or dilute,if necessary,a suitable volume of Injection to a concentration of about 10mg per mL.Apply 2µLof this solution and of a Standard solution of
USP Phenylephrine Hydrochloride RS,containing about 10mg per mL,at points about 2.5cm from the bottom edge of a suitable thin-layer chromatographic plate (see
Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Dry the spots in a current of warm air,and develop the chromatogram in a suitable chromatographic chamber with a mixture of methanol,water,and ammonium hydroxide (72:25:3)until the solvent front has moved about 12cm.Dry the plate in warm air,and spray it with alcoholic potassium hydroxide TS.Dry at 60

for 15minutes,and spray the plate with
p-nitroaniline TS:the reddish orange spot obtained from the test solution corresponds in color,size,and intensity to that obtained from the Standard solution.
Assay
Mobile phase
Prepare and filter a mixture of methanol and water (1:1)containing 1.1g of sodium 1-octanesulfonate per liter,adjusted with 3
Mphosphoric acid to a pHof 3.0.Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
Dilution solvent
Prepare a mixture of methanol and water (1:1),adjusted with 3Mphosphoric acid to a pHof 3.0.
System suitability solution
Dissolve about 50mg each of
USP Phenylephrine Hydrochloride RSand
USP Epinephrine Bitartrate RSin 5mLof water,dilute with
Dilution solventto 25.0mL,and mix.Further dilute 5.0mLof the resulting solution with
Dilution solventto 25.0mL,and mix to obtain a solution having a concentration of about 0.4mg of phenylephrine hydrochloride and 0.4mg of epinephrine bitartrate per mL.
Standard preparation
Dissolve about 50mg of
USP Phenylephrine Hydrochloride RS,accurately weighed,in 10mLof water,dilute with
Dilution solventto 25.0mL,and mix.Further dilute 5.0mLof the resulting solution with
Dilution solvent to 25.0mL,and mix to obtain a solution having a known concentration of about 0.4mg per mL.
Assay preparation
Transfer an accurately measured volume of Injection,equivalent to about 10mg of phenylephrine hydrochloride,to a 25-mLvolumetric flask.Dilute with Dilution solventto volume,and mix.
Chromatographic system
(see
Chromatography á621ñ)The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1mLper minute.Chromatograph the
System suitability solution,and record the responses for the major peaks:the resolution,
R,between epinephrine and phenylephrine is not less than 1.0.Chromatograph replicate injections of the
Standard preparation,and record the peak responses as directed for
Procedure:the relative standard deviation 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.Calculate the quantity,in mg,of C
9H
13NO
2·HCl in each mLof the Injection taken by the formula:
(25C/V)(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Phenylephrine Hydrochloride 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.