Decadentate Acyclic Chelators for Lanthanum Radiopharmaceuticals
Bibliographic record
Abstract
Abstract Two decadentate acyclic chelators bearing four picolinic acid groups appended on either an ethylenediamine (H4TPAEN) or a trans-1,2-cyclohexyldiamine (H4TPADAC) unit were explored as candidates for lanthanum-based radiopharmaceutical development. The two chelators form ten-coordinated complexes with La3+ in the solid state, as evidenced by the corresponding X-ray structures and solution NMR studies. The La3+ complexes of TPAEN4– and TPADAC4– are characterized by high thermodynamic stability constants of log KLaL = 19.16(8) and 19.55(1), respectively. Kinetics studies indicate that the complexes dissociate following the acid-catalyzed and Cu2+-assisted pathways. Quantitative radiolabeling of both chelators with [135La]La3+ was achieved at pH ∼ 4–5 using straightforward protocols and low concentrations of the chelator (3 μM). Both in vitro and in vivo studies indicate that the [135La]La3+ complex of TPAEN4– is significantly more stable than the TPADAC4– analogue, with the former remaining intact and stable even after 60 min in vivo when injected to healthy mice.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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) | 0.005 | 0.002 |
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 source (direct Gemma or distilled Codex), 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".