Skip to main content

Advertisement

Table 3 Characteristics of published a-synuclein deposition tracers

From: New protein deposition tracers in the pipeline

Tracer name Chemical structure Features
Aminothiazolyl-ethenyl-benzoxazole derivatives
 [11C] BF-227 (Kikuchi et al. 2010) • Non-selective, affinities: see below for 18F-derivative
• Investigated in MSA patients
 [18F] BF-227: (Fodero-Tavoletti et al. 2009) • Aß1-42 fibrils: KD1 = 1.3 nM
• α-syn fibrils: KD = 9.6 nM
Phenothiazine derivatives
 SIL23 (Bagchi et al. 2013) • Affinity and selectivity not optimal for in vivo imaging
• Affinity α-synuclein: Ki = 58 nM
• Screening tool
 [18F] 2b (Zhang et al. 2014) • Affinity α-synuclein: Ki = 49 nM
• Selectivity α -syn vs. Aß: 2-fold
• Selectivity α -syn vs. tau: 2.5-fold
• Crosses blood–brain-barrier in healthy cynomolgus macaques
• Shows sufficient initial uptake and wash-out
• Higher selectivity desired
 [11C] 2a (Zhang et al. 2014) • Affinity α-synuclein: Ki = 32 nM
• Selectivity α-syn vs. Aß: 3-fold
• Selectivity α-syn vs. tau: 4-fold
• Crosses blood–brain-barrier in cynomolgus macaques
• Shows sufficient initial uptake and wash-out
• Higher selectivity desired
3-(Benzylidene) indolin-2-one derivatives
 [18F] 46a: (Chu et al. 2015) • Selective for α-synuclein:
  o α-syn Kd = 8.9 nM
  o Aß Kd = 271 nM
  o Tau fibrils: 50 nM
• High logP and presence of nitro group may limit its use for in vivo PET studies
• Potential as secondary lead compound for further SAR studies