Class

Definition

Proposed action for control (details in Section 7 and 8)

1

Known mutagenic carcinogens

Control at or below compound-specific acceptable limit

2

Known mutagens with unknown carcinogenic potential (bacterial mutagenicity positive*, no rodent carcinogenicity data)

Control at or below acceptable limits (appropriate TTC)

3

Alerting structure, unrelated to the structure of the drug substance;

no mutagenicity data

Control at or below acceptable limits (appropriate TTC) or conduct bacterial mutagenicity assay;

If non-mutagenic = Class 5 If mutagenic = Class 2

4

Alerting structure, same alert in drug substance or compounds related to the drug substance (e.g., process intermediates) which have been tested and are non-mutagenic

Treat as non-mutagenic impurity

5

No structural alerts, or alerting structure with sufficient data to demonstrate lack of mutagenicity or carcinogenicity

Treat as non-mutagenic impurity