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The OECD 471 Ames test, a bacterial reverse mutation assay, is the most commonly requested genotoxicity study in regulatory testing frameworks and has been used for decades. The test investigates the ability of test substances to cause specific mutations in Salmonella or E. coli strains that allow them to then grow on selective agar plates. Used to detect DNA reactive mutagens, which have the potential to be highly potent in vivo, Ames positive results are taken very seriously when assessing safety.
Scantox has conducted these studies to GLP since 2014, and our senior study director has been working on Ames tests for over 40 years, meaning we have exceptional experience in this area.
| OECD 471 Ames Test Strains | TA98, TA100, TA1535, TA1537, TA102, TA97, TA97a, uvrA/pKM101, WP2 pKM101, WP2 uvrA |
| Metabolic activation | Typically induced rat liver S9, though other sources are available |
| Test Format | Plate incorporation, pre-incubation |
| Typical test item requirements | 1.5g |
| Formulation Analysis | Available upon request |
| Endpoint | Mutagenicity |
GLP OECD 471 Ames Test with Enhanced Conditions
The standard test conditions recommended in the Ames OECD 471 guideline are reported to have reduced sensitivity when assessing some N-nitrosamines or N-nitrosamine drug substance-related impurities (NDSRIs). To reliably detect the mutagenic potential of N-nitrosamines and NDSRIs, the FDA recommends that a negative result in a standard bacterial reverse mutation assay be followed by a second Ames test with enhanced testing conditions.
Scantox has optimized the OECD 471 Ames Test with Enhanced Conditions, which involved the generation of historical control data for rat and hamster S9 at 30% concentration and the full validation of two N-nitrosamines as additional positive controls.
| Study Format | Single Mutagenicity test |
| Tester Strains | TA98, TA100, TA1535, TA1537 and WP2 uvrA pKM101. |
| Test Method | The pre-incubation method, with 30 minutes pre-incubation time. |
| Metabolic Activation | Without S9; with rat S9 (30%); with hamster S9 (30%). S9 will be PB-NF induced. |
| Solvent | Water or lowest possible dosing volume of organic solvent. |
| Additional Positive Controls | N-nitroso-dimethylamine (NDMA) and 1-Cyclopentyl-4-nitrosopiperazine |