A: Infrared Absorption 197K.

B:Ultraviolet Absorption 197U—

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 (see System Suitability under Chromatography 621).

Standard stock solution— Dissolve an accurately weighed quantity of USP Flurbiprofen Related Compound A RS in Diluent to obtain a solution having a concentration of about 50 µg per mL.

System suitability solution— Pipet 2.0 mL of Standard stock solution into a 10-mL volumetric flask, add about 20 mg of USP Flurbiprofen RS, dilute with Diluent to volume, and mix.

Standard solution— Transfer 2.0 mL of Standard stock solution to a 10.0-mL volumetric flask, dilute with Diluent to volume, and mix.

Test solution— Prepare a solution of Flurbiprofen in Diluent containing 2.0 mg per mL.

Chromatographic system (see Chromatography 621)— 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 1 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.9 for flurbiprofen related compound A and 1.0 for flurbiprofen; and the relative standard deviation for replicate injections is not more than 1.0%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the percentage of flurbiprofen related compound A in the portion of Flurbiprofen taken by the formula: in which CS is the concentration, in µg per mL, of USP Flurbiprofen Related Compound A RS in the Standard solution; CU is the concentration, in µg per mL, of Flurbiprofen in the Test solution; and rU and rS are the peak responses for flurbiprofen related compound A obtained from the Test solution and the Standard solution, respectively: not more than 0.5% of flurbiprofen related compound A is found. Calculate the percentage of each impurity in the portion of Flurbiprofen taken by the formula: in which ri is the peak response for each impurity obtained from the Test solution; and rs is 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%.