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

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

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

(Official January 1, 2007)

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

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

Assay preparation— Using a “to contain” pipet, transfer an accurately measured volume of the Injectable Suspension, equivalent to about 40 mg of triamcinolone hexacetonide, to a 100-mL volumetric flask. Rinse the pipet with methanol, collecting the rinse in the volumetric flask. Dilute with methanol to volume, and mix.

Chromatographic system (see Chromatography 621)—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 1.4 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.50 for amcinonide and 1.0 for 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 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C30H41FO7 in the portion of Injectable Suspension taken by the formula: in which C is the concentration, in mg per mL, of USP Triamcinolone Hexacetonide RS in the Standard preparation, and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.