Lab and analysis
Residual solvents
Definition
Traces of process solvents left in a product, limited for pharmaceuticals by ICH Q3C.
ICH Q3C groups solvents into three classes. Class 1 solvents, such as benzene, should be avoided. Class 2 solvents, such as methanol and toluene, have permitted daily exposure limits. Class 3 solvents, such as ethanol and acetone, have low toxic potential.
Residual solvents are usually measured by headspace gas chromatography, following methods such as USP chapter 467 or the matching Ph. Eur. text.
Related terms
- Gas chromatography (GC)A separation method for volatile compounds, used for solvents, residual solvents and many organic intermediates.
- Impurity profile (related substances)The identity and amount of impurities in a material, often measured by HPLC as related substances.
- Elemental impuritiesTrace metals and other elements in a product, controlled for medicines by ICH Q3D.