Lyophilisation: difference between revisions
Diff·revision 19 → 20·01:48, 14 May 2025
Difference between revision 19 and revision 20 of Lyophilisation. 3 lines changed; the page grew by 645 bytes.
| Revision 19 — 06:21, 27 Apr 2025 Chromatokid (talk) add the crimp-seal step to the fill-and-finish description 20,900 bytes +873 | Revision 20 — 01:48, 14 May 2025 CDMO_Caradoc (talk) add the excursion tolerance with the study it derives from 21,545 bytes +645 | ||
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| 130 | For research peptides the formulation is frequently minimal — the peptide, its counterion, and whatever residue survives purification — because the material is sold as a chemical rather than as a dosage form. This has two consequences an encyclopedia should record. The cake is often small and poorly formed relative to a pharmaceutically formulated product, so cake appearance carries little information about quality; and the absence of a bulking agent means the mass in the vial is dominated by peptide, counterion and water, making [[Peptide content|peptide content]] rather than fill weight the meaningful quantity.{{r|usp1207}} | 130 | For research peptides the formulation is frequently minimal — the peptide, its counterion, and whatever residue survives purification — because the material is sold as a chemical rather than as a dosage form. This has two consequences an encyclopedia should record. The cake is often small and poorly formed relative to a pharmaceutically formulated product, so cake appearance carries little information about quality; and the absence of a bulking agent means the mass in the vial is dominated by peptide, counterion and water, making [[Peptide content|peptide content]] rather than fill weight the meaningful quantity.{{r|usp1207}} |
| 131 | 131 | ||
| + | 132 | === Counterion effects === | |
| + | 133 | Peptides purified by reverse-phase chromatography with trifluoroacetic acid as ion-pairing agent are isolated as trifluoroacetate salts unless a salt exchange is performed. Trifluoroacetate is hygroscopic, contributes appreciable mass, and lowers the pH of the reconstituted solution. Its presence also depresses the critical temperature of the freeze concentrate, lengthening the cycle. Acetate exchange is the usual remedy and is one of the routine differences between material intended as an [[Active pharmaceutical ingredient|active pharmaceutical ingredient]] and material sold for laboratory use.{{r|nail2002}} | |
| + | 134 | ||
| 132 | == References == | 135 | == References == |
| 133 | {{reflist}} | 136 | {{reflist}} |