Lyophilisation: difference between revisions
Diff·revision 32 → 33·08:46, 18 Feb 2025
Difference between revision 32 and revision 33 of Lyophilisation. 2 lines changed; the page grew by 529 bytes.
| Revision 32 — 12:03, 10 Feb 2025 ParentCatPansy (talk) correct percentage: source reports placebo-adjusted 17,113 bytes +237 | Revision 33 — 08:46, 18 Feb 2025 ResinRhoswen (talk) convert list to prose 17,642 bytes +529 | ||
|---|---|---|---|
| 110 | The heating ramp matters because the glass transition temperature of the partially dried solid rises as water leaves it. Early in secondary drying the solid is plasticised by residual water and its glass transition may be only slightly above the product temperature; heating too quickly can carry the product above the moving glass transition and cause the same collapse phenomenon seen in primary drying, at a much higher temperature. Conventional practice ramps shelf temperature at 0.1–0.5 °C per minute for this reason.{{r|tang2004}} | 110 | The heating ramp matters because the glass transition temperature of the partially dried solid rises as water leaves it. Early in secondary drying the solid is plasticised by residual water and its glass transition may be only slightly above the product temperature; heating too quickly can carry the product above the moving glass transition and cause the same collapse phenomenon seen in primary drying, at a much higher temperature. Conventional practice ramps shelf temperature at 0.1–0.5 °C per minute for this reason.{{r|tang2004}} |
| 111 | 111 | ||
| + | 112 | Residual moisture specifications for lyophilised peptides commonly sit below 3% w/w, and frequently below 1% for products intended for long ambient storage. Lower is not always better. For some proteins a monolayer of water appears to be required for conformational stability, and over-dried preparations have shown reduced stability relative to preparations dried to an intermediate moisture. The relationship between residual moisture and degradation rate is not monotonic and is formulation-specific.{{r|chang2009,wang2000}} | |
| + | 113 | ||
| 112 | == References == | 114 | == References == |
| 113 | {{reflist}} | 115 | {{reflist}} |