BIODISTRIBUTION AND KINETICS OF NASAL CARBON-11-TRIAMCINOLONE ACETONIDE

PET is a technique with a strong potential for use in drug evaluation and development. In particular, the distribution and pharmacokinetics of locally administered drugs may be advantageously explored noninvasi vely using labeled compounds. This pilot study was performed to demons trate the effectiveness of PET for drug development and to determine t he human biodistribution and kinetics of triamcinolone acetonide, labe led with C-11, formulated and nasally administered as Nasacort(R) AQ n asal inhalant. Methods: Carbon-11-labeled triamcinolone acetonide was formulated as the commercial product, and PET scans of the heads of fo ur volunteers were performed in a vertical orientation. Region-of-inte rest analysis with MRI coregistration was used to analyze the distribu tion and kinetics in nasal tissues. Results: Deposition of the majorit y of the dose on target tissues was immediate. Penetration into sinuse s was observed. There was moderate redistribution and slow migration o f the drug through nasal passages to the throat. Significant amounts o f the drug remained in target regions for several hours. Conclusion: P ET is an effective means to determine local drug distribution and kine tics.