Class 3 Residual Solvents
Residual solvents are separated into three classes based on risk assessment or their potential toxicity level. Class 3 residual solvents are limited by GMP or other quality-based requirements in drug substances, excipients, and
drug products.
As outlined in USP <467>, analysis of Class 3 solvents is performed by USP Loss on drying <731> provided the test is specified in the monograph. If there is no LOD specified or the limit is greater than 0.5%, a suitable validated method will be required for analysis.

USP Class 3 Residual Solvents List
| Acetic acid | Heptane |
| Acetone | Isobutyl acetate |
| Anisole | Isopropyl acetate |
| 1-Butanol | Methyl acetate |
| 2-Butanol | 3-Methyl-1-butanol |
| Butyl acetate | Methylethylketone |
| tert-Butylmethyl ether | Methylisobutylketone |
| Cumene | 2-Methyl-l-propanol |
| Dimethyl sulfoxide | Pentane |
| Ethanol | 1-Pentanol |
| Ethyl acetate | 1-Propanol |
| Ethyl ether | 2-Propanol |
| Ethyl formate | Propyl acetate |
| Formic acid |
Learn more about Residual Solvents...

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