18F-labeled flavones for in vivo imaging of ƒÀ-amyloid plaques in Alzheimer's
In vivo imaging of ƒÀ-amyloid (AƒÀ) aggregates in the brain may lead to early detection of Alzheimer's disease (AD) and monitoring of the progression and effectiveness of treatment. The purpose of this study was to develop novel 18F-labeled amyloid-imaging probes based on flavones as a core structure. Fluoropegylated (FPEG) flavone derivatives were designed and synthesized. The affinity of the derivatives for AƒÀ aggregates varied from 5 to 321nM. In brain sections of AD model mice, FPEG flavones with the dimethylamino group intensely stained ƒÀ-amyloid plaques. In biodistrubution experiments using normal mice, they displayed high uptake in the brain ranging from 2.9 to 4.2%ID/g at 2 min postinjection. The radioactivity washed out from the brain rapidly (1.3-2.0%ID/g at 30 min), which is highly desirable for ƒÀ-amyloid imaging agents. FPEG flavones may be potential PET imaging agents for ƒÀ-amyloid plaques in Alzheimer's brains.