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Key value for chemical safety assessment

Additional information

Valid in vitro data to assess the genetic toxicity of N,N-Dimethyldecanamide are available.

In vitro tests with pure N,N-Dimethyldecanamide:

The test substance N,N-Dimethyldecanamide was tested in a salmonella typhimurium reverse mutation assay (TA1535,TA1537,TA98,TA100and TA102) according to OECD 471 guideline (Cognis 1999; Hans-Eric Wollny) with and without metabolic activation. The test item was tested at the following concentrations:(TA98,TA100): 3; 10; 33; 100; 333; and 1000 µg/plate and(TA1535,TA1537,TA102): 33; 66; 100; 333; 666; and 1000 µg/plate.Toxic effects, evident as a reduction in the number of revertants, occurred between 333 and 1000µg/plate depending on strain and activation. No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with N,N-Dimethyldecan-1 -amide at any dose level, neither in the presence nor absence of metabolic activation (S9 mix).In conclusion the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.

In vitro tests with mixtures of N,N-Dimethylamides:

A mixture of N,N-dimethyldecanamide and N,N-Dimethyloctanamide (with traces of N,N-dimethyl-dodecanamide and ~5% N,N-dimethyl-hexanamide) was tested in an in vitro mammalian chromosome abberation test (CHO cells) and in an V79-HGPRT Forward Mutation Assay (V79 cells). It is concluded that, caused by a high amount of N,N-Dimethyl-decanamide in the mixture and the fact that the residual contains homologues with a lower and higher molecular weight (mainly N,N-Dimethyloctanamide) which can be assumed to have an similar toxicological behaviour as the mixture, the mixture has an similar behaviour in the different cell tests like pure N,N-Dimethyldecanamide. Therefore the following study results will be used for assessing the genetoxic behaviour of N,N-Dimethyldecanamide.

The genotoxic potential of a C8/C10 dimethylamide mixture was tested in an in vitro mammalian chromosome abberation test according to OECD 473 (Bayer 1995; R. Gahlmann). Therefore Chinese hamster ovary cells were treated with the substance at the concentrations of 10, 40 and 160 µg/ml medium without S9 mix and at the concentrations of 7.2, 36 and 180 µg/ml with S9 mix. The test substance induced cyto toxic effects in cells exposed to the highest doses with and without metabolic activation at the early harvest time of 8 hours after the beginning of the treatment. The mitotic indices were markedly reduced to 66.7 and 43.2 % relative to control cells. With one exception (which was considered as uncritical, see study summary), no statistically significant or biologically relevant increases of numbers of metaphases with aberrations were detected 8, 24 or 30 hours after the beginning of the four hour treatment with the test substance with and without S9 mix. Therefore the C8/C10 mixture not considered to be clastogenic for mammalian cells with and without metabolic activation

A further study was accomplished to observe the genotoxic potential of C8/C10 FADMA (Bayer, 1994, Brendler-Schwaab S.). Therefore the test material was assayed for mutagenic activity at the HGPRT locus in V79 cells from 25 to 250 µg/ml both, with and without metabolic activation according to OECD guideline 476. Under both treatment conditions, cyto toxic effects were induced. The vehicle control mutant frequencies were all in the normal range of background frequencies for the assay. In contrast, the positive controls and DMBA induced a distinct mutagenic effect in mutant frequency, which was significantly increased over the negative controls demonstrating the sensitivity of the test system and the ability to detect known mutagens. The test substance was considered to be non mutagenic in the V79-HGPRT Forward Mutation Assay both with and without metabolic activation.

Assessment of genetic toxicity

In summary there were no hints for gene mutation or cytogenicity from the pure N,N-Dimethyldecanamide

or from the C8/C10 dimethylamide mixture in the different in vitro genotoxicity tests. Following the mutagenicity testing stragegy no in vivo experiment is proposed due to this result.

Key study assignment:

For each specific in vitro endpoint is only one reliability study with the substance identity identical to submission (highst priority) or read across substance (second priority) available.Therefore all studies were integrated as key studies.

Short description of key information:
- Salmonella typhimurium reverse mutation assay (N,N-Dimethyldecanamide; TA1535,TA1537,TA98,TA100and TA102), OECD 471:
non-mutagenic (with and without metabolic activation) (Cognis 1999; Hans-Eric Wollny)
- V79-HGPRT (mixture of N,N-Dimethyldecanamide and N,N-Dimethyloctanamide; V79), OECD 476: non mutagenic (with and without metabolic activation) (Bayer, 1994, Brendler-Schwaab S.)
- Chromosome abberation test (mixture of N,N-Dimethyldecanamide and N,N-Dimethyloctanamide; CHO cells), OECD 473:
not clastogen (with and without metabolic activation) (Bayer 1995; R. Gahlmann)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

In vitro genotoxicity test and in vitro mutagenicity test does not reveal a positive result.

Due to criteria of GHS (Regulation (EU) 1272/2008) for germ cell mutagens ("The classification in Category 2 is based on: positive evidence obtained from experiments in mammals and/or in some cases from in vitro experiments, obtained from: somatic cell mutagenicity tests in vivo, in mammals; or other in vivo somatic cell genotoxicity tests which are supported by positive results from in vitro mutagenicity assays....") the substance is not to classify as germ cell mutagen. Also according to EU-criteria DSD (67/548/EEC) the available information does not lead to a classification.

Labelling genotoxicity/mutagenicity:

GHS: no classification

DSD: no classification