abstract |
This invention relates to a new process for preparing (11 β , 16 α )-9-fluoro-11-hydroxy-16, 17-[1-methyl-ethylidenebis(oxy)]-21-[1-oxo-[4-(nitrooxymethyl)benzoxy]]pregna-1, 4-dien-3, 20-dione, comprising the steps of (i) reaction of triamcinolone acetonide with 4-(nitrooxymethyl)benzoic, 4-dimethylaminopyridine and N-N'-diisopropylcarbodiimide, (ii) crystallisation, and (iii) controlled precipitation. |