A: Dissolve a portion of it in acetone,and evaporate to dryness:the IRabsorption spectrum of a mineral oil dispersion of the residue so obtained,previously dried at a pressure not exceeding 5mm of mercury at 105for 4hours,exhibits maxima only at the same wavelengths as that of a similar preparation of USP Prednisolone Tebutate RS.

B: Ultraviolet Absorption á197Uñ—

Test solution: 10mg per mL,in chloroform.

Mobile solvent— Prepare a mixture of isooctane,tetrahydrofuran,and alcohol (89:10:1).

Standard preparation— Dissolve a suitable quantity of USP Prednisolone Tebutate RS,accurately weighed,in a mixture of tetrahydrofuran and isooctane (1:1)to obtain a solution having a known concentration of about 1mg per mL.

Assay preparation— Weigh accurately about 50mg of Prednisolone Tebutate,transfer to a 50-mLvolumetric flask,dilute with tetrahydrofuran and isooctane (1:1)to volume,and mix.

Procedure— Inject separately 25-µLvolumes of the Standard preparationand the Assay preparationinto a suitable high-pressure liquid chromatograph equipped with a constant flow pump and a 30-cm ×3.9-mm column that contains packing L3,is operated at 25,and is equipped with an UVdetector capable of monitoring absorption at 254nm.The flow rate is about 1.0mLper minute.The retention time for Prednisolone Tebutate is about 30minutes,but the chromatogram is run for about 45minutes.Five replicate injections of the Standard preparationshow a relative standard deviation of not more than 1.5%.Calculate the quantity,in mg,of C27H38O6in the portion of Prednisolone Tebutate taken by the formula: in which Cis the concentration,in mg per mL,of USP Prednisolone Tebutate RSin the Standard preparation,and RUand RSare the peak areas obtained from the Assay preparationand the Standard preparation,respectively.