Comparison of Pharmacokinetic Properties of 4 TSPO Ligands, Including Kinetic Parameters Measured in Human Subjects
| Ligand | cLogP | fP (%) | Ki/(PK11195 Ki) | K1 (mL/cm3/min) | VT (mL/cm3) |
|---|---|---|---|---|---|
| 11C-R-PK11195 | 5.11 | 1.0 | 1 | 0.016–0.026 | 0.25–0.42 |
| 11C-DPA-713 | 2.63 | 9.0 | 0.5 (30) | 0.20–0.29 | 3.1–5.1 |
| 11C-PBR28 | 3.29 | 3.3 (15) | 0.22–0.93 (31) | 0.10–0.14 (15) | 3.3–4.6 (15) |
| 11C-DAA1106 | 4.38 | ND | 0.053–0.099 (31) | 0.048–0.066 (32) | 3.8–5.0 (32) |
cLogP = calculated log of octanol-to-water partition coefficient; ND = not determined.
Range of K1 values represents measurements obtained in different tissue regions. Values of Ki/(PK11195 Ki) are ratio of Ki of ligand to Ki of PK11195 and are taken from measurements in mitochondrial tissue. Range of Ki ratios represents values taken from different species including rat, monkey, and human. For 11C-DPA-713, ratio was measured with rat mitochondria only. Values that do not have reference were determined in present study. cLogP was computed with ACD/PhysChem Suite (Advanced Chemistry Development).