PREPARATION OF [C-11] TRIAMCINOLONE ACETONIDE

Triamcinolone acetonide is commercially available in a variety of formulations for local administration as an anti-inflammatory agent. In order to evaluate the effectiveness of various dosage methods and the kinetics of subsequent absorption and distribution, the acetonide was labeled 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 carrier, and yields of 15-25% were obtained by adding carrier acetone. Without added carrier, it was necessary to add triethyl orthoformate in order to achieve reasonable yields of acetonide. The time required for synthesis was 45 min.