Lyophilisation: difference between revisions
Diff·revision 57 → 58·15:19, 23 Sep 2025
Difference between revision 57 and revision 58 of Lyophilisation. 8 lines changed; the page grew by 506 bytes.
| Revision 57 — 19:16, 11 Sep 2025 DisparityDagny (talk) link to the policy rather than restating it 27,583 bytes +1,208 | Revision 58 — 15:19, 23 Sep 2025 FmocFrancis (talk) add PMID 28,089 bytes +506 | ||
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| 146 | Headspace composition is set at stoppering. Vials sealed under partial vacuum or under nitrogen exclude oxygen and thereby suppress [[Methionine oxidation|methionine oxidation]] during storage; vials sealed at atmospheric pressure in air do not. Headspace pressure is measurable non-destructively by laser-based headspace analysis, which is also used as a container-closure integrity method under USP <1207>.{{r|usp1207}} | 146 | Headspace composition is set at stoppering. Vials sealed under partial vacuum or under nitrogen exclude oxygen and thereby suppress [[Methionine oxidation|methionine oxidation]] during storage; vials sealed at atmospheric pressure in air do not. Headspace pressure is measurable non-destructively by laser-based headspace analysis, which is also used as a container-closure integrity method under USP <1207>.{{r|usp1207}} |
| 147 | 147 | ||
| + | 148 | | Attribute | Detects | Does not detect | | |
| + | 149 | |---|---|---| | |
| + | 150 | | Cake appearance | Collapse, melt-back, gross underfill | Chemical degradation, moisture | | |
| + | 151 | | Residual moisture | Under-drying, closure moisture transfer | Structural collapse in itself | | |
| + | 152 | | Reconstitution time | Collapse, aggregation, over-concentration | Counterion identity | | |
| + | 153 | | Assay and purity | Chemical degradation | Physical cake quality | | |
| + | 154 | | Headspace analysis | Loss of container integrity, oxygen ingress | Anything about the solid itself | | |
| + | 155 | ||
| 148 | == Why lyophilised material tolerates ambient shipping == | 156 | == Why lyophilised material tolerates ambient shipping == |
| 149 | The practical significance of lyophilisation for distribution is that it removes the dominant degradation pathway. Hydrolytic reactions require water and molecular mobility; a dry amorphous glass held below its glass transition temperature provides neither in quantity. Reported consequences are large. Degradation rates for peptides in the dry state are commonly two to three orders of magnitude below rates for the same peptide in solution at the same temperature, and the temperature sensitivity of the residual degradation is correspondingly lower.{{r|chang2009,wang2000}} | 157 | The practical significance of lyophilisation for distribution is that it removes the dominant degradation pathway. Hydrolytic reactions require water and molecular mobility; a dry amorphous glass held below its glass transition temperature provides neither in quantity. Reported consequences are large. Degradation rates for peptides in the dry state are commonly two to three orders of magnitude below rates for the same peptide in solution at the same temperature, and the temperature sensitivity of the residual degradation is correspondingly lower.{{r|chang2009,wang2000}} |