A: Infrared Absorption á197Kñ.

B: Ultraviolet Absorption á197Uñ—

Solution: 10µg per mL.

Test solution: 10mg per mL,in chloroform.

Mobile phase and Chromatographic system—Proceed as directed in the Assay.

Test preparation— Transfer about 25mg of fluocinonide,accurately weighed,to a 10-mLvolumetric flask,add acetonitrile to volume,and mix.

Procedure— Inject 30µLof the Test preparationinto the chromatograph,record the chromatogram,and measure the area responses of all peaks.Calculate the area percentage of each peak observed in the chromatogram.The largest secondary peak is not more than 1.0%of the total area,and no other secondary peak is more than 0.5%of the total area.The sum of the areas of all peaks,other than the main peak,does not constitute more than 2.0%of the total area.

Mobile phase— Prepare a filtered and degassed mixture of acetonitrile and water (1:1).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Transfer about 25mg of USP Fluocinonide RS,accurately weighed,to a 100-mLvolumetric flask,add acetonitrile to volume,and mix.Transfer 10.0mLof this solution to a 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix to obtain a solution having a known concentration of about 0.025mg of USP Fluocinonide RSper mL.

Assay preparation— Using about 25mg of Fluocinonide,accurately weighed,proceed as directed for Standard preparation.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm ×30-cm column that contains packing L1.The flow rate is about 2mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation for replicate injections is not more than 1.5%.

Procedure— Separately inject equal volumes (about 30µL)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 C26H32F2O7in the portion of Fluocinonide taken by the formula: in which Cis the concentration,in mg per mL,of USP Fluocinonide RSin the Standard preparation;and rUand rSare the peak responses due to the fluocinonide obtained from the Assay preparationand the Standard preparation,respectively.