Ifosfamide pharmacokinetics and hepatobiliary uptake in vivo investigated using single‐ and double‐resonance <sup>31</sup>P MRS
Bibliographic record
Abstract
MRS has considerable potential for the measurement of drug pharmacokinetics in vivo. In this study single- and double-resonance (31)P MRS was used to investigate the biodistribution, pharmacokinetics, and metabolism of ifosfamide following administration of 500 mg/kg ifosfamide in guinea pigs. (1)H-decoupling was found to nearly double the signal of detected peaks. However, in contrast to studies of ifosfamide in solution, the polarization transfer sequence gave no further signal enhancements. This was attributed to significantly reduced relaxation times in vivo. Chemical shift imaging (CSI) measurements showed that significant proportions of ifosfamide-related (31)P MRS signals arose from the liver, as expected, but also from the gall bladder, which was not predicted from the current literature. Signals were observed within 5 min of the end of administration. The halflife in liver was approximately 74 min, whereas in gall bladder there was no measurable signal decay during the 2.5-hr studies. High-resolution (31)P MRS of bile showed that the "ifosfamide" peak in vivo consists of at least two compounds. The lower-concentration peak is ifosfamide, and an investigation is under way to identify the higher-concentration peak. Other peaks observed in bile are tentatively assigned to carboxy-ifosfamide and dechloroethyl-ifosfamide. Overall, (1)H-decoupled (31)P MRS has proved to be a useful tool for investigating the metabolism of ifosfamide in vivo.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".