ICH Q3C: Corrected Version of the Guideline for Residual Solvents Published

Since the end of April 2022, the revision of the "ICH guideline Q3C (R8) on impurities: guideline for residual solvents" of the ICH (INTERNATIONAL COUNCIL FOR HARMONISATION OF TECHNICAL REQUIREMENTS FOR PHARMACEUTICALS FOR HUMAN USE) can be consulted on the ICH website under the heading "Quality Guidelines". This version has now been corrected and published in its new form.

Basically, the guideline is divided into four chapters (with respective subchapters), a glossary, three appendices and five so-called "Parts II-VI" for PDE values. In the following list of the table of contents you will find the individual topics and subtopics of the guideline:

1. Introduction
2. Scope of the guideline
3. General principles
     3.1. Classification of residual solvents by risk assessment
     3.2. Methods for establishing exposure limits
     3.3. Options for describing limits of class 2 solvents
     3.4. Analytical procedures
     3.5. Reporting levels of residual solvents
4. Limits of residual solvents
     4.1. Solvents to be avoided
     4.2. Solvents to be limited
     4.3. Solvents with low toxic potential
     4.4. Solvents for which no adequate toxicological data was found
Glossary
Appendix 1. List of solvents included in the guideline
Appendix 2. Additional background
    A2.1 Environmental regulation of organic volatile solvents
    A2.2 Residual solvents in pharmaceuticals
Appendix 3. Methods for establishing exposure limits
Part II: PDE for Tetrahydrofuran
Part III: PDE for N-Methylpyrrolidone (NMP
Part IV: PDE for Cumene
Part V: PDE for Triethylamine and PDE of Methylisobutylketone
Part VI: PDE for 2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and Tertiary-Butyl Alcohol

In the corrected version of the guideline, methyltetrahydrofuran was removed from Table 4 in chapter "4.4. Solvents for which no adequate toxicological data was found".

The corrected "ICH guideline Q3C (R8) on impurities: guideline for residual solvents" as well as all other valid "Quality (Q)-Guidelines" can be consulted on the ICH website.