Pharmacokinetic Modulation of Radiolabeled Chelates Facilitated by Phosphonate Ester Coordinating Groups
Bibliographic record
Abstract
Chelates are an important part of metal based radiopharmaceuticals. This study examines the possible application of phosphonate ester moieties incorporated into chelates, where the ester group can be changed to modulate the pharmacokinetics of the radiopharmaceutical, while the phosphonate stably binds the metal radioisotope. Two phosphonate ester containing chelates, PCTMB and PCTM(F)E, were compared to the carboxylate containing analogue, p-Bn-PCTA, with respect to radiochemistry with several radionuclides (In-111, Ga-68, Ga-67, Cu-64). The phosphonate ester derivatives were similar to p-Bn-PCTA with respect to efficient radiolabeling with each of the radiometals under mild, aqueous conditions. Each of the radiolabeled phosphonate esters was also shown to be stable under physiological conditions in vitro. The phosphonate ester moieties did exhibit a propensity to degrade under more acidic conditions. Biodistribution studies in mice with the In-111 radiolabeled versions of PCTMB, PCTM(F)E and p-Bn-PCTA demonstrated the ability of the phosphonate ester functionalities to change the pharmacokinetics of the BFCs. With increasing lipophilicity, the phosphonate ester derivatives showed increasing hepatic clearance; but no significant increase in background tissue uptake (bone, muscle) was observed, and all the In-111 radiolabeled BFCs were substantially cleared within 24 h. The substitution of phosphonate ester for carboxylate functional groups in chelates may be an effective strategy to assist in optimizing the pharmacokinetics of radiopharmaceuticals through varying of the ester group.
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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 | 0.000 | 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".