A: Infrared Absorption á197Mñ.

B: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that of the Standard preparation,both relative to the internal standard,as obtained in the Assay.

Test solution: 5mg per mLin dioxane.

Standard solutions— Dissolve an accurately weighed quantity of USP Mometasone Furoate RS,and dilute quantitatively with dichloromethane to obtain a solution containing 10mg per mL.Dilute portions of this solution with dichloromethane to obtain Standard solutions A,B,C,D,and Econtaining 0.5(5%),0.2(2%),0.1(1%),0.02(0.2%),and 0.01(0.1%)mg per mL,respectively.

Test solution— Prepare a solution of Mometasone Furoate in dichloromethane containing 10mg per mL.

Procedure— Separately apply 40µLof the Test solution,and Standard solutions A,B,C,D,and Eto a thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Develop the chromatogram in a chamber,previously equilibrated with a solvent system consisting of a mixture of chloroform and ethyl acetate (3:1),until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and air-dry.Examine the plate under short-wavelength UVlight.Compare the intensities of any secondary spots observed in the chromatogram of the Test solutionwith those of the principal spots in the chromatogram of the Standard solutions:no secondary spot from the chromatogram of the Test solutionis larger or more intense than the principal spot obtained from Standard solution C,and the sum of the intensities of the secondary spots obtained from the Test solutionis not more than 2.0%.

Mobile phase— Prepare a filtered and degassed mixture of methanol and water (65:35).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Diluting solution— Prepare a solution consisting of a mixture of methanol,water,and acetic acid (65:35:0.2).

Internal standard solution— Transfer about 40mg of beclomethasone dipropionate to a 100-mLvolumetric flask,dilute with Diluting solutionto volume,and mix.

Standard preparation— Dissolve an accurately weighed quantity of USP Mometasone Furoate RSin methanol,and dilute quantitatively,and stepwise if necessary,with Diluting solutionto obtain a solution having a known concentration of about 0.1mg per mL.Pipet equal amounts of this solution and the Internal standard solution,and dilute quantitatively,and stepwise if necessary,with Diluting solutionto obtain a solution having a known concentration of about 0.02mg per mLfor mometasone furoate and 0.08mg per mLfor beclomethasone dipropionate.

Assay preparation— Dissolve an accurately weighed quantity of Mometasone Furoate in methanol,and dilute quantitatively,and stepwise if necessary,with Diluting solutionto obtain a solution having a concentration of about 0.1mg per mL.Pipet 10.0mLof this solution and 10.0mLof the Internal standard solutioninto a 50-mLvolumetric flask,dilute with Diluting solutionto volume,and mix.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains packing L7.The flow rate is about 1.7mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed under Procedure:the relative retention times are about 1.6for beclomethasone dipropionate and 1.0for mometasone furoate,the resolution,R,between the mometasone furoate and beclomethasone dipropionate peaks is not less than 4.0,the tailing factor for the mometasone furoate peak is not more than 1.8,and the relative standard deviation for replicate injections 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 C27H30Cl2O6in the portion of Mometasone Furoate taken by the formula: in which Cis the concentration,in mg per mL,of USP Mometasone Furoate RSin the Standard preparation,and RUand RSare the ratios of the mometasone furoate peak to the internal standard peak obtained from the Assay preparationand the Standard preparation,respectively.