ICH Q3C Revisited Part II: Safety Assessments for Three Acetal Residual Solvents

In ICH Q3C, first released in 1997, nine residual solvents are described as "solvents for which no adequate toxicological data was found". Nearly thirty years later the same nine solvents lie "abandoned" in ICH Q3C (R9) in spite of the fact that, in most cases, sufficient toxicological data are now available to support an adequate risk assessment. The solvents in question represent several chemical types: three are acetals, two are haloacids, two are hydrocarbons, plus one ketone and one ether. This article concerns the three acetals which are all considered to be of low toxicity.