Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

GENETIC TOXICITY IN VITRO

Dioctadecyldimethylammonium chloride (DODMAC, 90% in isopropanol/water) as well as the structural analogue Dihydrogenatedbenzylmethyl ammonium chloride (purity 96%) were investigated for genetic toxicity in three in vitro tests.

1- Gene mutation in bacteria:

One study on gene mutation in bacteria is available. The Hoechst study (Hoechst AG 1982) was reliable with some restrictions: study predates GLP requirements but the method used is similar to OECD guideline 471.

The Hoechst study (1982 ) was designed to evaluate in a bacterial reverse mutation assay (Ames test) the genotoxic properties of DODMAC (90% active in isopropanol/water) regarding point mutation.

The tester strains Salmonella typhimurium TA100, TA1535, TA1537, TA1538 and TA98, and Escherichia coli strain WP2uvrA were exposed to the test substance in the presence and absence of metabolic activation (S9 mix). In a preliminary toxicity study, the test substance was found to be very toxic to the bacteria at concentrations of 2500 µg/plate and above, therefore 1000 µg/plate was chosen as the top dose for S. typhimurium and 2500 µg/plate was chosen as the top dose for E. coli. The test substance did not cause a dose-related significant increase in the number of revertant colonies in any of the strains tested, both with and without metabolic activation. It was concluded that the test material was not mutagenic under the conditions of the study.

2- Chromosomal aberrations in mammalian cells:

One in vitro study on chromosome aberration is available.The Hoechst study (Hoechst AG 1989) performed according to OECD guideline 473 and Good Laboratory Practices was considered as reliable without restriction.

The potential genotoxic effect of DODMAC (90% active in isopropanol/water) was tested using Chinese Hamster lung fibroblasts (V79), both in the presence and absence of metabolic activation in the form of S-9 mix. The limit of solubility in culture medium was 200 µg/ml. Cytoxicity was observed 18 and 28 hours after treatment at 40 µg/ml without S9 but the test substance did not demonstrate an increase in the number of chromosome aberrations with or without metabolic activation compared to negative controls. Based on these results, it was concluded that the substance did not show any clastogenic activity in the in vitro mammalian chromosome aberration test with V79 chinese Hamster cells.

3- Gene mutation in mammalian cells:

The endpoint gene mutation in mammalian cells is covered by read across from a respective study conducted with the structurally closely related substance 'benzyl-di-C16-18-alkylmethylammonium chloride' as test item instead of the substance ' di-C16-18-alkyldimethylammonium chloride'. The former is produced by the reaction of the N-C16 -C18 dialkylmethylamine with benzyl choride while the latter is produced by reaction of the N-C16 -C18 dialkylamine with methylhalide. Therefore the reaction products are structurally closely related and the negative result concerning gene mutation in bacteria for 'benzyl-di-C16-18 -alkylmethylammonium chloride' can be extrapolated to 'di-C16-18 -alkyldimethylammonium chloride'.

In the study of Sarlang (2010), the potential of the substance to induce mutations at the TK locus, was investigated in L5178Y mouse lymphoma cells according to OECD guideline 476 and Good Laboratory Practice. The test substance was tested in two independent experiments, both with and without metabolic activation. Since the test item was toxic in the preliminary test, the choice of the highest dose-level for the main experiments was based on the level of toxicity. Cytotoxicity was observed following the 3-hour and the 24 -hour treatments both with and without metabolic activation but no noteworthy increase in the mutation frequency was noted in comparison to controls. Based on these results, it was concluded that the substance did not show any mutagenic activity in the in vitro mammalian cell gene mutation test with L5178Y TK+/- mouse lymphoma cells.

Based on all available results, there is no indication of a mutagenic potential for quaternary ammonium compound, di-C16 -18 -alkyldimethyl, chloride. Moreover, two evaluation reports on the structural closely related DidecylDimethylAmmonium Chloride (DDAC) have been recently published by the European Competent Authorities and conclude that the substance was of no concern for genetic toxicity (Document I- Draft Evaluation reports in the frame of the directive 98/8/EC concerning the placing of biocidal products on the market - DDAC CAS 7173 -51 -5- Product type 8 - RMS Italy, July 2007 and April 2010).


Short description of key information:
The genetic toxicity of quaternary ammonium compound, di-C16-18-alkyldimethyl, chloride was assessed using:

- One in vitro bacterial reverse mutation test. The study predates GLP requirements but the described method is similar to the OECD guideline 471 (Hoechst, 1982).

- An in vitro chromosomal aberration assay in V79 Chinese Hamster cells performed according to OECD guideline 473 and Good laboratory practices (Hoechst, 1989).

- An in vitro gene mutation assay in mouse lymphoma L5178Y cells performed according to OECD guideline 476 and Good laboratory practices with a structural analogue (Sarlang, 2010).

In all of those in vitro studies negative results were reported in the presence and absence of metabolic activation.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the results of available studies and according to the criteria laid down in EU regulation (EC) n° 1272/2008 (CLP) and the EU directive 67/548/EEC, quaternary ammonium compound, di-C16 -18 -alkyldimethyl, chloride should not be classified for genetic toxicity as all in vitro mutagenicity assays are negative.