PREPARATION OF [C-11] TRIAMCINOLONE ACETONIDE

Triamcinolone acetonide is commercially available in a variety of form ulations for local administration as an anti-inflammatory agent. In or der to evaluate the effectiveness of various dosage methods and the ki netics of subsequent absorption and distribution, the acetonide was la beled with carbon-11 for use in PET studies. Labeled acetone was used as a synthetic intermediate and reacted with triamcinolone to produce the acetonide. Chemical yields of 5-10% were obtained without added ca rrier, and yields of 15-25% were obtained by adding carrier acetone. W ithout added carrier, it was necessary to add triethyl orthoformate in order to achieve reasonable yields of acetonide. The time required fo r synthesis was 45 min.