2-tert-butylcyclohexyl ethyl carbonate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames Test (OECD 471, GLP, K, rel. 1): non mutagenic up to 5000 µg/plate in S. typhimurium TA 1535, TA 1537, TA 98, TA 100 & E.coli WP2uvrA.
Ames Test (similar to OECD 471, GLP, K, rel. 1): non mutagenic up to 5000 µg/plate in S. typhimurium TA 1535, TA 1537, TA 98, TA 100 & E.coli WP2uvrA.
Micronucleus Test (OECD 487, GLP, K, rel. 1): non-clastogenic and non-aneugenic to human lymphocytes in vitro up to 96 µg/mL.

MLA-hprt (OECD 476, GLP, K, rel. 1): non mutagenic at the hprt locus of L5178Y mouse lymphoma cells up to toxic, or highly toxic concentrations.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Test n°	Test / Guideline Reliability	Focus	Strains tested	Metabolic activation	Test concentration	Statement
1  (Envigo, 2016)	Ames Test (OECD 471) K, rel. 1	Gene mutation	TA 1535, TA 1537, TA 98, TA 100 E.coli WP2 uvrA	-S9 +S9	Up to cytotoxic concentration	-S9 : non mutagenic +S9 : non mutagenic
2 (Japan Biological Science Centre Genetic Laboratory, 2003)	Japanese method similar to Ames Test (OECD 471) K, rel. 1	Gene mutation	TA 1535, TA 1537, TA 98, TA 100, E. coli WP2 uvrA	-S9 +S9	Up to cytotoxic concentration	-S9 : non mutagenic +S9 : non mutagenic
3 (Envigo, 2016)	MNT vitro (OECD 487) K, rel.1	Chromosomal aberration	Human lymphocytes	-S9 +S9	Up to cytotoxic concentration	-S9 and +S9 Not clastogenic -S9 and +S9 Not aneugenic
4 (Covance, 2016)	MLA hprt (OECD 476) K, rel. 1	Gene mutation	L5178Y mouse lymphoma cells	-S9 +S9	Up to toxic, or highly toxic concentrations	-S9 : non mutagenic +S9 : non mutagenic

Gene mutation Assay (Test No. 1, 2 and 4):

Two Bacterial Reverse mutation Assay (Ames test) were performed, according to, and similar to OECD test guideline No 471 with the substance, respectively.

In the first study (1), only in the pre-experiment/experiment I, reduced background growth was observed in the presence of S9 mix at 5000 µg/plate in strains TA 100 and WP2 uvrA. The test substance precipitated in the overlay agar in the test tubes in experiment I from 1000 to 5000 µg/plate in the presence of S9 mix. Precipitation of the test substance in the overlay agar on the incubated agar plates was observed at 5000 µg/plate in experiment I in strains TA 1535, TA 1537, and TA 98 in the presence of S9 mix. The undissolved particles had no influence on the data recording. Toxic effects, evident as a reduction in the number of revertants (below the indication factor of 0.5), occurred only in strain TA 100 in all experiments. No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with the test substance at any dose level, neither in the presence nor absence of metabolic activation (S9 mix).

 

In the second study (2), the test substance caused no visible reduction in the growth of the bacterial background lawn at any dose level. The test substance was, therefore, tested up to the maximum recommended dose level of 5000 μg/plate. No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test material, either with or without metabolic activation.

In an in vitro mammalian cell gene mutation test (4) performed according to OECD Guideline 476 and in compliance with GLP, L5178Y tk+/-(3.7.2C) mouse lymphoma cells were exposed to test substance for 3h with six concentrations from 15.63 to 500 µg/mL in the range-finder experiment, with and without S9, and with twelve concentrations from 2.5 to 100 µg/mL without S9 and from 30 to 300 µg/mL with S9 in the Mutation experiment. When tested up to toxic concentrations in the presence or absence of S-9 no statistically significant increases in mutant frequency, compared to the vehicle control MF, were observed following treatment with the test articleat any concentration analysed and there were no statistically significant linear trends, indicating a clear negative result.

It is concluded thatwith the test articledid not induce mutation at thehprtlocus of L5178Y mouse lymphoma cells when tested up to toxic concentrations for 3 hours in the presence or absence of a rat liver metabolic activation system (S-9).

Moreover, the results of a supporting study (Gloxhuber, 1978) are according to the key-studies results.

 

Chromosomal aberration (Test No. 3):

An in vitro micronucleus test was performed according to OECD Guideline 487 and in compliance with GLP, cultured peripheral human lymphocytes were exposed to test substance in the presence and absence of a metabolic activation system. The test substance was toxic to human lymphocytes. Depending on the preliminary study results, the test substance was therefore tested up to 64 or 96 µg/mL without or with metabolic activation, respectively.

The test substance did not induce any statistically significant increases in the frequency of cells with micronuclei, using a dose range that included a dose level that induced approximately 50% reduction in CBPI in the absence of S9-mix and was the lowest precipitating dose level in the presence of S9-mix.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Harmonized classification:

The substance has no harmonized classification for human health according to the Regulation (EC) No. 1272/2008.

Self classification:

Based on the available data, no additional classification is proposed regarding genetic toxicity according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP) and to the GHS.