4-(1,1,3,3-tetramethylbutyl)phenol

Endpoint summary

Additional information

In a reverse gene mutation assay in bacteria, strains TA 98, TA 100, TA 1535, TA 1537, TA 1538 of S. typhimurium were exposed to o-1,1,3,3-Tetramethylbutylphenol (95.6%) in DMSO at concentrations of 8, 40, 200, 1000, 5000 µg/plate in the presence and absence of mammalian metabolic activation in a pre-incubation assay. o-1,1,3,3-Tetramethylbutylphenol was tested up to a limit concentration of 5000 µg/plate. The positive controls induced the appropriate responses in the corresponding strains. There was no evidence of induced mutant colonies over background. This study is classified as acceptable. This study satisfies the requirement for Test Guideline EC 84/449/EEC B.14 for in vitro mutagenicity (bacterial reverse gene mutation) data.

In this study (AM-91/11) the ortho-isomer of the substance that is going to be registered was used. With regards to the mutagenic potential both isomers should be comparable. In addition the negative result is supported by a second Ames test listed in the Japanese Existing Chemicals Data Base conducted with para-tert-octylphenol.

 

In a mammalian cell cytogenetics assay, V79 cell cultures were exposed to 4-(1,1,3,3-Tetramethylbutyl)-phenol (98,1%) in ethanol at concentrations of 0 / 0.313 / 1.25 / 2.5 µg/ml with and without metabolic activation. 4-(1,1,3,3-Tetramethylbutyl)-phenol was tested up to precipitating concentrations. Positive controls induced the appropriate response. There was no evidence of Chromosome aberration induced over background. This study is classified as acceptable. This study satisfies the requirement for Test Guideline OECD 473 for in vitro cytogenetic mutagenicity data. 

The result is supported by a second CA test listed in the Japanese Existing Chemicals Data Base. 4-(1,1,3,3-Tetramethylbutyl)-phenol is not a clastogenic agent.

 

In a mammalian cell HRPT gene forward mutation assay, CHO cells cultured in vitro were exposed to 4-(1,1,3,3-Tetramethylbutyl)-phenol (98,1%) in ethanol at concentrations of 0 / 0.25 / 0.625 / 1.25 / 2.0 / 2.5 µg/mL in the presence and absence of mammalian metabolic activation (S9). 4-(1,1,3,3-Tetramethylbutyl)-phenol was tested up to insoluble concentrations. The highest concentration induced 10 +/-4 mutants/10^-6vs. 1 +/-2 mutants/10^-6in the negative control. The positive controls did induce the appropriate response. There was no evidence of induced mutant colonies over background. This study is classified as acceptable. This study satisfies the requirement for Test Guideline OECD 476 for in vitro mutagenicity (mammalian forward gene mutation) data.

 

The overall conclusion is that 4-(1,1,3,3-Tetramethylbutyl)-phenol can be considered as non-mutagenic.

Short description of key information:
The mutagenic potential of 4-(1,1,3,3-Tetramethylbutyl)-phenol was evaluated in two in vitro gene mutation study in bacteria (Ames test), two in vitro mammalian chromosome aberration tests and one mammalian cell gene mutation assay (HPRT). There was no incidence of mutagenic effects.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

4-(1,1,3,3-Tetramethylbutyl)-phenol was found not to be mutagenic in any test system. The test battery covers the requirements of the REACH regulation.