Fluocinonide Gel
»Fluocinonide Gel contains not less than 90.0percent and not more than 110.0percent of the labeled amount of fluocinonide (C26H32F2O7).
Packaging and storage— Preserve in collapsible tubes or tight containers.
Identification— Weigh an amount of Gel,equivalent to about 2.5mg of fluocinonide,into a glass-stoppered,50-mLcentrifuge tube containing 20mLof sodium chloride solution (1in 10).Add 5mLof chloroform and 15mLof methanol,and shake vigorously.Centrifuge to clarify the chloroform layer,and remove the solid material present at the interphase.Discard the upper phase.Dry a portion of the chloroform layer over anhydrous sodium sulfate.Using the dried extract as the Test preparation,proceed as directed in the Identificationtest under Fluocinonide Cream,beginning with “Apply 10µLof the Test solution.”
Minimum fill á755ñ: meets the requirements.
Assay—
Mobile phase— Prepare a mixture of acetonitrile and water (1:1).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard preparation— Dissolve an accurately weighed quantity of USP Fluocinonide RSin acetonitrile to obtain a solution having a known concentration of about 200µg per mL.Transfer 10.0mLof this solution to a 100-mLvolumetric flask,dilute with acetonitrile to volume,and mix.The final concentration is 20µg per mL.
Assay preparation— Transfer an accurately weighed quantity of Gel,containing about 2mg of fluocinonide,to a 100-mLvolumetric flask.Add about 60mLof acetonitrile,and dissolve the gel by heating on a steam bath.Cool to room temperature,dilute with acetonitrile to volume,and mix.Centrifuge a portion at about 2500rpm for about 5minutes.Filter a portion of the centrifugate through an acetonitrile-insoluble membrane filter.The filtrate is the Assay 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 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 C26H32F2O7in the portion of Gel taken by the formula:
0.1C(rU/rS),
in which Cis the concentration,in µg per mL,of USP Fluocinonide RSin the Standard preparation;and rUand rSare the peak responses due to fluocinonide obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 842
Phone Number:1-301-816-8139