Lyophilisation: difference between revisions
Diff·revision 25 → 26·23:04, 14 Sep 2025
Difference between revision 25 and revision 26 of Lyophilisation. 5 lines changed; the page grew by 1,208 bytes.
| Revision 25 — 23:37, 20 Aug 2025 Chromatokid (talk) add the reconstitution-stability sentence with its storage condition 26,375 bytes +1,596 | Revision 26 — 23:04, 14 Sep 2025 IcodecIndra (talk) add the cross-link to the temperature-excursion article 27,583 bytes +1,208 | ||
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| 153 | The evidence available for any particular unregulated product is usually nil. A manufacturer's stability programme conducted under [[Cold chain|cold-chain]] and ICH conditions produces data that support a labelled storage statement; material distributed without such a programme carries a storage recommendation that is, at best, an inference from the behaviour of similar compounds.{{r|ich_q1a}} Community-collated observations of material that appeared to perform normally after warm transit exist but are self-reported, unblinded, and without pre-excursion analytical baselines, and cannot establish the absence of degradation.{{r|ppcommunity}} | 153 | The evidence available for any particular unregulated product is usually nil. A manufacturer's stability programme conducted under [[Cold chain|cold-chain]] and ICH conditions produces data that support a labelled storage statement; material distributed without such a programme carries a storage recommendation that is, at best, an inference from the behaviour of similar compounds.{{r|ich_q1a}} Community-collated observations of material that appeared to perform normally after warm transit exist but are self-reported, unblinded, and without pre-excursion analytical baselines, and cannot establish the absence of degradation.{{r|ppcommunity}} |
| 154 | 154 | ||
| + | 155 | == Scale-up and transfer == | |
| + | 156 | A cycle developed on a laboratory dryer frequently fails when transferred, and the reasons are well characterised. Radiative heat load differs between a small chamber with a glass door and a large chamber with cold walls, so the distribution of product temperatures differs. Condenser capacity and duct conductance limit the maximum sublimation rate a large dryer can sustain; when the rate approaches that limit, flow through the duct becomes choked and chamber pressure rises above its set point, warming every vial simultaneously. Shelf-temperature uniformity and the flatness of shelves both affect the vial heat transfer coefficient.{{r|rambhatla2003,tang2004}} | |
| + | 157 | ||
| + | 158 | Quality-by-design approaches address this by constructing a design space in terms of the two variables that actually constrain the process — the maximum sublimation rate the equipment can support, and the shelf temperature at which the product would reach its critical temperature — and locating the operating point inside both boundaries. Presented graphically, this is conventionally called a design-space or primary-drying diagram, and it makes explicit that a cycle is equipment-specific.{{r|tang2004}} | |
| + | 159 | ||
| 155 | == References == | 160 | == References == |
| 156 | {{reflist}} | 161 | {{reflist}} |