Impact of Crystal Structure and Polymer Excipients on the Melt Crystallization Kinetics of Itraconazole Polymorphs
Bibliographic record
Abstract
The crystal structure of itraconazole (ITZ) Form II has been determined by single-crystal X-ray diffraction, and the effects of crystal structure and two polymer excipients, Kollidone VA64 (PVPVA64) and hydroxypropylmethyl cellulose acetate succinate (HPMCAS), on the melt crystallization kinetics of ITZ Forms I and II have been investigated. Form II structure is characterized by a unit cell similar to that of Form I, but with a different orientation of the dichlorophenyl groups. Form II displays a considerably higher crystal growth rate than Form I, which cannot be explicated by their difference in crystal density alone. Both polymers at 20% (w/w) significantly retard the crystallization of Forms I and II without altering the crystal structure of either polymorph. Crystallization kinetic analysis by the two-dimensional surface nucleation model suggests that the polymers inhibit the crystallization of ITZ from amorphous dispersions by reducing the molecular mobility in the molten state as well as augmenting the crystal–melt interfacial free energy. Form II is more sensitive than Form I to the growth inhibition by either polymer, which can be attributed to a much larger increase in the crystal–melt interfacial free energy brought about by much stronger polymer adsorption on the crystal surface of Form II.
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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 | 0.000 | 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".