Efficient radiosynthesis and preclinical evaluation of [<sup>18</sup>F]FOMPyD as a positron emission tomography tracer candidate for TrkB/C receptor imaging
Bibliographic record
Abstract
Herein we report an efficient radiolabeling of a 18 F‐fluorinated derivative of dual inhibitor GW2580, with its subsequent evaluation as a positron emission tomography (PET) tracer candidate for imaging of two neuroreceptor targets implicated in the pathophysiology of neurodegeneration: tropomyosin receptor kinases (TrkB/C) and colony stimulating factor receptor (CSF‐1R). [ 18 F]FOMPyD was synthesized from a boronic acid pinacolate precursor via copper‐mediated 18 F‐fluorination concerted with thermal deprotection of the four Boc groups on a diaminopyrimidine moiety in an 8.7±2.8% radiochemical yield, a radiochemical purity >99%, and an effective molar activity of 187±93 GBq/μmol. [ 18 F]FOMPyD showed moderate brain permeability in wild‐type rats (SUV max = 0.75) and a slow washout rate. The brain uptake was partially reduced (ΔAUC 40–90 = 11.6%) by administration of the nonradioactive FOMPyD (up to 30 μg/kg). In autoradiography, [ 18 F]FOMPyD exhibits ubiquitous distribution in rat and human brain tissues with relatively high nonspecific binding revealed by self‐blocking experiment. The binding was blocked by TrkB/C inhibitors, but not with a CSF‐1R inhibitor, suggesting selective binding to the former receptor. Although an unfavorable pharmacokinetic profile will likely preclude application of [ 18 F]FOMPyD as a PET tracer for brain imaging, the concomitant one‐pot copper‐mediated 18 F‐fluorination/Boc‐deprotection is a practical technique for the automated radiosynthesis of acid‐sensitive PET tracers.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".