Impurity profile and spectrum characteristics of the isomers in cefamandole nafate using high‐ performance liquid chromatography/high‐performance size exclusion chromatography tandem ion trap/time‐of‐flight mass spectrometry
Bibliographic record
Abstract
Rationale Reversed‐phase, high‐performance liquid chromatography (RP‐HPLC) and high‐performance size exclusion chromatography (HPSEC) methods were developed to effectively separate unknown impurities and polymerized impurities in cefamandole nafate. The liquid chromatography‐tandem ion trap/time‐of‐flight mass spectrometry (LC‐IT‐TOF‐MS) was applied to characterize the structures of the impurities. Ultraviolet (UV) spectrum characteristics and mass spectrum characteristics of △ 3 ‐isomer and 7‐epimer in cefamandole nafate were studied to distinguish the isomers. Methods RPLC‐IT‐TOF‐MS was used to characterize the structures of unknown impurities and polymerized impurities eluted from the C 18 column. On this basis, the two‐dimensional (2D) HPSEC‐IT‐TOF‐MS was used to confirm the structures of polymerized impurities eluted from the TSK‐gel G2000SWxl column. Complete fragmentation patterns of impurities were studied and used to obtain information about the structures of the impurities. Results The structures of 19 unknown impurities in cefamandole nafate were elucidated based on the high‐resolution MS n data with both positive and negative modes, assisted by the UV spectra and stress testing, of which 2 impurities were polymerized impurities. Cefamandole nafate produced a series of degradation impurities, and another principal component cefamandole acid also produced a series of similar degradation impurities. The disciplines between mass fragmentation pattern/UV spectrum and structure for △ 3 ‐isomer and 7‐epimer were presented to distinguish their structures. Conclusions The results of this study provided a scientific basis for the improvement of official monographs in pharmacopoeias to effectively control the impurities and ensure drug safety for the public. This study also revealed the formation mechanisms of degradation impurities in cefamandole nafate, which may guide industry to improve the manufacturing process and storage conditions to reduce the content of impurities in products.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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 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".