Triamcinolone Acetonide Cream »Triamcinolone Acetonide Cream is Triamcinolone Acetonide in a suitable cream base.It contains not less than 90.0percent and not more than 115.0percent of the labeled amount of C24H31FO6. Packaging and storage— Preserve in tight containers. USP Reference standards á11ñ USP Triamcinolone Acetonide RS. Identification— Place a 2-g quantity of Cream in a conical flask,add 50mLof chloroform and 15g of anhydrous sodium sulfate,and swirl to dissolve the specimen.Filter the solution and clarify the filtrate,if necessary,by the further addition of anhydrous sodium sulfate and a second filtration.Evaporate the filtrate to near dryness,and dissolve the residue in chloroform to obtain a solution containing about 100µg per mL.Apply 10µLof this solution and 10µLof a solution of USP Triamcinolone Acetonide RSin chloroform containing 100µg per mL,on a line parallel to and about 1.5cm from the bottom edge of a thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Place the plate in a developing chamber containing and equilibrated with a mixture of chloroform,benzene,and methanol (100:40:20).Develop the chromatogram until the solvent front has moved about 12cm above the line of application.Remove the plate,allow the solvent to evaporate,and spray with a mixture of equal volumes of sodium hydroxide solution (1in 5)and a 1in 500solution of blue tetrazolium in methanol:the intensity of the blue color and the RFof the spot obtained with the solution under test are similar to those of the spot obtained with the Standard solution. Microbial limits á61ñ It meets the requirements of the tests for absence of Staphylococcus aureusand Pseudomonas aeruginosa. Minimum fill á755ñ: meets the requirements. Assay— Mobile phase— Prepare a solution of acetonitrile in water containing approximately 30%(v/v)of acetonitrile. Internal standard solution— Dissolve fluoxymesterone in isopropyl alcohol to obtain a solution having a concentration of about 50µg per mL. Standard preparation— Dissolve an accurately weighed quantity of USP Triamcinolone Acetonide RSin Internal standard solutionto obtain a solution having a known concentration of about 75µg per mL.Mix an accurately measured volume of the resulting solution with an equal volume of Mobile phaseto obtain a Standard preparationcontaining about 37.5µg of USP Triamcinolone Acetonide RSper mL. Assay preparation— Transfer an accurately weighed quantity of Cream,equivalent to about 1.5mg of triamcinolone acetonide,to a screw-cap tube.Add 20.0mLof Internal standard solution,and cap securely.Heat for 5minutes at 60,then swirl vigorously for not less than 30seconds.Repeat the heating and swirling sequence three times.Cool in a methanol-ice bath for 15to 20minutes,then centrifuge for 15minutes at -5.Dilute an accurately measured volume of the supernatant with an equal volume of Mobile phase.Cool in a methanol-ice bath for 10to 15minutes,with occasional agitation.Filter first through a pledget of glass wool or a prefilter disk and then through a 0.45-µm porosity membrane to obtain a clear solution. Procedure— Introduce equal volumes (between 15and 25µL)of the Assay preparationand the Standard preparationinto a high-pressure liquid chromatograph (see Chromatography á621ñ),operated at room temperature,by means of a suitable microsyringe or sampling valve.Adjust the operating parameters with Mobile phaseon the column,such that the separation of triamcinolone acetonide and internal standard is optimized,with a retention time of about 14.5minutes for triamcinolone acetonide.Typically,the apparatus is fitted with a 30-cm ×4-mm column containing packing L1,and is equipped with a UVdetector capable of monitoring absorbance at 254nm,and a suitable recorder.In a suitable chromatogram,the coefficient of variation for five replicate injections of a single specimen is not more than 3.0%,and the resolution factor,R(see Chromatography á621ñ),between the peaks for triamcinolone acetonide and fluoxymesterone is not less than 2.0.Measure the heights of the internal standard and triamcinolone acetonide peaks,at the same retention times obtained from the Assay preparationand the Standard preparation.Calculate the quantity,in mg,of C24H31FO6in the portion of Cream taken by the formula: 40C(RU/RS), in which Cis the concentration,in mg per mL,of USP Triamcinolone Acetonide RSin the Standard preparation,and RUand RSare the ratios of the peak heights of triamcinolone acetonide to the internal standard 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 1960 Phone Number:1-301-816-8139