Identification—
Place 2g of Ointment in a conical flask,add 5.0mLof chloroform,and shake for 10minutes.Add 15mLof alcohol,and shake for an additional 10minutes.Filter the solution into a centrifuge tube,and evaporate the filtrate to dryness.Dissolve the residue in alcohol to obtain a solution containing about 250µg per mL.Apply 10µLof this solution,and 10µLof a solution of
USP Triamcinolone Acetonide RSin alcohol containing 250µg 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 from the solution under test are similar to those of the spot obtained from the Standard solution.