Assay preparation
Transfer an accurately weighed quantity of Dental Paste,equivalent to about 1.5mg of triamcinolone acetonide,to a screw-cap tube.Add 20.0mLof
Internal standard solution,cap,and place in a sonic bath for 15to 20minutes.Place in a water bath at 70

for 5minutes,then swirl for 1minute.Repeat the heating and swirling sequence once.Cool in an icemethanol bath for 15minutes,then centrifuge for 10minutes at
-5

.Mix an accurately measured volume of the supernatant with an equal volume of
Mobile phase.Place in an icemethanol bath for 15minutes,then centrifuge for 15minutes.Draw off and discard the upper phase.Filter the lower phase to obtain a clear solution.