• The classification of residual solvents is primarily based on their toxicity and potential risk to human health. The International Conference on Harmonisation (ICH) has categorized these solvents into three classes. Class 1 solvents are those that are prohibited due to their unacceptable toxicity, such as benzene and carbon tetrachloride. Class 2 solvents are limited because of their potential toxicity and include solvents like methanol and dichloromethane. Class 3 solvents are considered to have low toxic potential and are typically acceptable in pharmaceutical manufacturing, provided their levels are controlled and monitored.

  • – condiments, spices;