A: Infrared Absorption á197Kñ.

B:Ultraviolet Absorption á197Uñ—

C: Heat 0.5mLof a saturated solution of chromium trioxide in sulfuric acid in a water bath for 5minutes:the solution wets the sides of the tube readily and there is no greasiness.Add 2or 3mg of Flurbiprofen and heat in a water bath for 5minutes:the solution does not wet the sides of the tube and does not pour easily.

Diluent— Prepare a mixture of water and acetonitrile (11:9).

Mobile phase— Prepare a filtered and degassed mixture of water,acetonitrile,and glacial acetic acid (12:7:1).Make adjustments if necessary (seeSystem SuitabilityunderChromatography á621ñ).

Standard stock solution— Dissolve an accurately weighed quantity ofUSP Flurbiprofen Related Compound A RSinDiluentto obtain a solution having a concentration of about 50µg per mL.

System suitability solution— Pipet 2.0mLofStandard stock solutioninto a 10-mLvolumetric flask,add about 20mg of USP Flurbiprofen RS,dilute withDiluentto volume,and mix.

Standard solution— Transfer 2.0mLofStandard stock solutionto a 10.0-mLvolumetric flask,dilute withDiluentto volume,and mix.

Test solution— Prepare a solution of Flurbiprofen inDiluentcontaining 2.0mg per mL.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm ×15-cm column that contains 4-µm packing L1.The flow rate is about 1mLper minute.Chromatograph theSystem suitability solution,and record the peak responses as directed forProcedure:the relative retention times are about 0.9for flurbiprofen related compound Aand 1.0for flurbiprofen;and the relative standard deviation for replicate injections is not more than 1.0%.

Procedure— Separately inject equal volumes (about 20µL)of theStandard solutionand theTest solutioninto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the percentage of flurbiprofen related compound Ain the portion of Flurbiprofen taken by the formula: in whichCSis the concentration,in µg per mL,of USP Flurbiprofen Related Compound A RSin theStandard solution;CUis the concentration,in µg per mL,of Flurbiprofen in theTest solution;andrUandrSare the peak responses for flurbiprofen related compound Aobtained from theTest solutionand theStandard solution,respectively:not more than 0.5%of flurbiprofen related compound Ais found.Calculate the percentage of each impurity in the portion of Flurbiprofen taken by the formula: in which riis the peak response for each impurity obtained from the Test solution;and rsis the sum of the responses of all the peaks obtained from the Test solution:the sum of all impurities is not more than 1.0%.