Polymorphic Crystallization and Transformation of the Anti-Viral/HIV Drug Stavudine
Bibliographic record
Abstract
The effect of supersaturation, nucleation temperature, cooling rate and solvent on the polymorphic crystallization of stavudine has been studied. Supersaturation is found to be the predominant controlling factor for the occurrence of polymorphs. When stavudine crystallizes from methanol or 2-propanol, form I nucleates preferentially at a low supersaturation level, whereas form II can be obtained at a high supersaturation level. When 1-butanol is used as solvent, apart from forms I and II, a newly found metastable form IV can crystallize out at a moderate supersaturation level. The relative stability of the above three polymorphs in decreasing order is: I > IV > II. In addition, the polymorphic transformation of stavudine in 2-propanol from form II to form I has been investigated by in situ Raman spectroscopy. The transformation rate is found to be accelerated significantly by increasing temperature and seeding with form I.
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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) | 0.001 | 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".