is representative of the antiinflammatory compositions of the present invention ______________________________________component wt ______________________________________4 9 11 pregnadien 17 u03b1 21 diol 3 20 1 0dione 21 acetatedexamethasone 0 1tyloxapol 0 01 to 0 05hpmc 0 5benzalkonium chloride 0 01sodium chloride 0 8edetate disodium 0 01naoh hcl q s ph 7 4purified water q s 100 ml______________________________________ the above formulation is prepared in the same manner set forth in example 2 sterilizing and adding the dexamethasone to the steroid before placing both into a pressurized ballmill container a solution of 4 75 g 17 3 mmol of t butyldiphenylchlorosilane in 5 ml of dry dmf was added dropwise to a stirred solution of 5 7 g 15 6 mmol of tetrahydrocortisol f steraloids no p9050 and 2 3 g 19 mmol of 4 dimethylaminopyridine dnap in 30 ml of dry dhf under n 2 at 25 u00b0 to 30 u00b0 c maintained with co 2 mecn after a further 20 min at 30 u00b0 c the mixture was allowed to warm to 23 u00b0 c overnight the mixture was partitioned between ether and water and the organic solution was washed with brine dried mgso 4 filtered and concentrated to give 10 7 g of a white foam this material was purified by flash column chromatography 400 g silica 62 5 to 70 ether hexane the 3 siloxy isomer eluted first followed by mixed fractions followed by the title compound the concentrated mixed fractions 4 0 g were chromatographed on the same column with 35 ethyl acetate hexane the total yield of the 3 siloxy isomer was 0 42 g 5 and of the title compound 5 05 g 53 5 continued elution with heoh etoac allowed recovery of unreacted tetrahydrocortisol f nmr 200 hhz.