USP: Possibility to Comment on the "Residual Solvents" Chapter

As recently reported, 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) has been updated and can be consulted on the ICH website under the heading "Quality Guidelines". As a result, the USP chapter "<467> Residual Solvents" has now been revised and posted for comment on the USP Pharmacopeial Forum website. Comments and suggestions on this draft can be submitted until 31 March 2023.

In addition to formal changes, the main adjustments and additions were made to the following sections and the associated tables, figures and appendices:

• 4.2 Class 2-Solvents to Be Limited
• 4.3 Class 3-Solvents with Low Toxic Potential
• 8.1 Chromatographic Systems
• 8.2 Screening of Water-Soluble Articles
• 8.3 Screening of Water-Insoluble Articles 
• 8.5 Quantitative Tests-Procedure C
• 9. Analytical Procedures for Class 3 Residual Solvents
• Appendix 1: Residual Solvents Included in this General Chapter
• USP Reference Standards <11>

The changes in these sections and appendices resulted from the inclusion and integration of two Class 2 substances, "cyclopentyl methyl ether" and "tertiary butyl alcohol" and a Class 3 substance called "2-methyltetrahydrofuran" (see, for example, Table 3 and Table 4). This also had the effect of updating the texts in sections 8 and 9. Similarly, adjustments have been made to the list of reference substances that follows on from the annexes to chapter <467>.

You can consult and comment on the draft chapter "<467> Residual Solvents" after completing a one-time registration on the Pharmacopeial Forum website.