Mobile phase ,System suitability solution,and Chromatographic system—Proceed as directed in the Assay.

Standard solution and Test solution—Use the Standard preparationand the Assay preparation,respectively,and proceed as directed in the Assay.

Procedure— Separately inject equal volumes (about 10µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the responses for all of the peaks.The Test solutionmay exhibit a minor peak for triamcinolone acetonide whose retention time is 0.22relative to triamcinolone hexacetonide.Calculate the percentage of triamcinolone acetonide in the portion of Injectable Suspension taken by the formula: in which Cis the concentration,in mg per mL,of USP Triamcinolone Hexacetonide RSin the Standard solution,Dis the concentration,in mg per mL,of triamcinolone hexacetonide in the Test solution,and rUand rSare the peak responses for triamcinolone acetonide obtained for the Test solutionand Standard solution,respectively:not more than 1.0%is found.

Mobile phase and Standard preparation—Proceed as directed in the Assayunder Triamcinolone Hexacetonide.

System suitability solution— Dissolve suitable quantities of amcinonide and USP Triamcinolone Hexacetonide RSin methanol to obtain a solution containing about 0.3mg per mLand 0.4mg per mL,respectively.

Assay preparation— Using a “to contain”pipet,transfer an accurately measured volume of the Injectable Suspension,equivalent to about 40mg of triamcinolone hexacetonide,to a 100-mLvolumetric flask.Rinse the pipet with methanol,collecting the rinse in the volumetric flask.Dilute with methanol to 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 L1.The flow rate is about 1.4mLper minute.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the relative retention times are about 0.50for amcinonide and 1.0for triamcinolone hexacetonide,the resolution,R,between amcinonide and triamcinolone hexacetonide is not less than 10,the tailing factor for triamcinolone hexacetonide is not more than 1.2,and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 10µL)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 C30H41FO7in the portion of Injectable Suspension taken by the formula: in which Cis the concentration,in mg per mL,of USP Triamcinolone Hexacetonide RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.