Table 1 Preclinical properties of the tau-specific PET tracers

Radiotracer

¹¹C

cold

¹⁸F

³H

¹⁸F

¹⁸F

³H

In vitro binding

Brain tissue

Kd₁ = 2.5 [28]

Bmax₁ = 25nM [28]

Kd₂ = 100 [28]

Bmax₂ = 300nM [28]

Kd = 5.19 [15]; 11.5 [14]

Bmax = 338 [15]

Kd₁ = 2.2^a; 3.1^b [24]

Kd₂ = 23.6^a; 34.6^b [24]

Bmax₁ = 250^a; 250^b [24]

Bmax₂ = 1416^a; 1226^b [24]

Kd = 2.9 [26]

Bmax = 368.3 [26]

15^f [22]

Kd = 1.4–3.72^c; 0.63–1.70^d [23]

Bmax = 15–62.5nM^c;

46.9–119.7nM^d [23]

Ki

Ki₁ = 1.3^b; 5.9^e [33]

Ki₂ = 23.5^b [33]

Ki₁ = 0.001^a; 0.0005^b [24]

Ki₂ = 27.4 [14]; 16^a [24]; 10.5 [15]

Ki₃ = 750^a; 800^b [24]

Ki₁ = 0.3^b; 3.3^e [33]

Ki₂ = 97.2^b [33]

Ex vivo biodistribution

LogP

2.32 [15]

1.5 [26]

1.67 [18]

Uptake in mouse brain (2 min)

6.06%ID/g [15]

4.36%ID/g [26]

7.5%ID/g [29]