Lyophilisation: difference between revisions
Diff·revision 9 → 10·08:35, 27 Nov 2024
Difference between revision 9 and revision 10 of Lyophilisation. 2 lines changed; the page grew by 508 bytes.
| Revision 9 — 10:14, 16 Nov 2024 StubSorterBot (talk) bot: flag bare reference 10,259 bytes +907 | Revision 10 — 08:35, 27 Nov 2024 CrossRefCleve (talk) state that overlay gas is used and name it 10,767 bytes +508 | ||
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| 63 | | Sodium chloride | Eutectic ≈ −21.1 °C | Crystallises | | 63 | | Sodium chloride | Eutectic ≈ −21.1 °C | Crystallises | |
| 64 | 64 | ||
| + | 65 | Figures are collated from the freeze-drying literature and vary with concentration and with the measurement method.{{r|nail2002,tang2004}} The presence of sodium chloride is significant for peptide formulations because its low eutectic temperature drags the critical temperature of the whole system downward, forcing a colder and therefore longer primary drying step. A formulation carrying appreciable [[Trifluoroacetate counterion|trifluoroacetate]] or phosphate salt from purification behaves similarly. | |
| + | 66 | ||
| 65 | == Primary drying == | 67 | == Primary drying == |
| 66 | Primary drying removes the ice, which for a typical aqueous fill is 90–98% of the water present. Its duration is set by the sublimation rate, which in the simplest treatment follows from an energy balance across the vial base: the mass flow equals the heat flow divided by the enthalpy of sublimation. | 68 | Primary drying removes the ice, which for a typical aqueous fill is 90–98% of the water present. Its duration is set by the sublimation rate, which in the simplest treatment follows from an energy balance across the vial base: the mass flow equals the heat flow divided by the enthalpy of sublimation. |