Residual solvent: difference between revisions
Diff·revision 9 → 10·19:12, 9 Jan 2025
Difference between revision 9 and revision 10 of Residual solvent. 6 lines changed; the page grew by 727 bytes.
| Revision 9 — 09:20, 17 Dec 2024 BetaCellBoyd (talk) ce 2,880 bytes ±0 | Revision 10 — 19:12, 9 Jan 2025 IncretinIvo (talk) add the plate-count expression and define its terms 3,607 bytes +727 | ||
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| 1 | {{Infobox concept | 1 | {{Infobox concept |
| 2 | | name = Residual solvent | 2 | | name = Residual solvent |
| + | 3 | | subtitle = Impurity class | |
| 3 | | Governing guidance = ICH Q3C; USP <467> | 4 | | Governing guidance = ICH Q3C; USP <467> |
| 4 | | Determined by = Headspace gas chromatography | 5 | | Determined by = Headspace gas chromatography |
| ⋮ | ⋮ | ||
| 22 | 23 | ||
| 23 | Dimethylformamide is the solvent most characteristic of peptide synthesis and is a Class 2 solvent with a comparatively low limit. Its persistence in a dried peptide depends on the drying regime and on whether an intermediate solvent exchange was performed, and it contributes to any [[Loss on drying|loss-on-drying]] figure obtained on the same material.{{r|usp1503,usp731}} | 24 | Dimethylformamide is the solvent most characteristic of peptide synthesis and is a Class 2 solvent with a comparatively low limit. Its persistence in a dried peptide depends on the drying regime and on whether an intermediate solvent exchange was performed, and it contributes to any [[Loss on drying|loss-on-drying]] figure obtained on the same material.{{r|usp1503,usp731}} |
| + | 25 | ||
| + | 26 | == Determination and its blind spots == | |
| + | 27 | Headspace gas chromatography is well suited to volatile analytes and is the compendial method. Its principal limitation is that it is a targeted determination: the instrument is calibrated for a named set of solvents, and anything outside that set is not reported even if it is present and volatile.{{r|usp467}} | |
| + | 28 | ||
| + | 29 | A certificate reporting "residual solvents: conforms" is therefore reporting conformity with respect to whichever solvents were in the method. A certificate itemising the solvents tested, with a result for each, is a substantially stronger document — the same argument that applies to itemised related substances at [[Limit of detection]]. | |
| 24 | 30 | ||
| 25 | == References == | 31 | == References == |