Miristalkonium chloride

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Based on the results of an in vitro Ames test, mammalian cytogenicity and mammalian gene mutation assays with read across substance, the test substance, C14 ADBAC, can be considered to be non-genotoxic.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Study 1: A study was conducted to determine the in vitro genetic toxicity of the read across substance, C12 -16 ADBAC, according to OECD Guideline 471, EU Method B13/14 and US EPA OPPTS 850.5100 (Ames test), in compliance with GLP. The mutagenic potential was investigated in Salmonella typhimurium strains A1535, TA1537, TA102, TA98 and TA100 with and without metabolic activation. Six dose levels of the test substance for each bacterial strain were tested in triplicate with and without a metabolic activation system. The dose range was determined in a preliminary toxicity assay and was 0.15 to 50 µg/plate in the first experiment. The experiment was repeated on a separate day using the same dose range, fresh cultures of the bacterial strains and fresh test substance formulations. Additional dose levels were included in both experiments to allow for test substance-induced toxicity and to ensure there were a minimum of four non-toxic doses plated out. The vehicle (sterile distilled water) control plates produced counts of revertant colonies within the normal range. All the positive control chemicals used in the test produced marked increases in the frequency of revertant colonies, both with and without the S9 -mix. No test substance precipitate was observed on the plates at any of the doses tested in either the presence or absence of S9-mix. No significant increase in the frequency of revertant colonies was recorded for any of the bacterial strains with any dose of the test substance, either with or without metabolic activation. Under the study conditions, the test substance was found to be non-mutagenic with and without metabolic activation (Thompson, 2001). Based on the results of the read across substance, the test substance, C14 ADBAC, is considered to be non-mutagenic in bacteria, with and without metabolic activation.

Study 2: A study was conducted to determine the in vitro genetic toxicity of the read across substance, C12 -16 ADBAC (active ingredient: >93%), according to OECD Guideline 473 and EU Method B.10 (chromosome aberration test), in compliance with GLP. This experiment was performed in human lymphocyte cells. Duplicate cell cultures of human lymphocytes, treated with the test substance, were evaluated for chromosome aberrations at three dose levels, together with vehicle and positive controls (mitomycin-C (without S9) and cyclophosphamide (with S9)). Four treatment conditions were used for the study. Experiment 1 and 4 h exposure with and without metabolic activation was followed by a 20 h expression period. In Experiment 2, the 4 h exposure with metabolic activation was repeated while in the absence of metabolic activation the exposure time was increased to 24 h. The doses studied were 0, 4, 8, 16, 20 µg/mL (with and without activation) in Experiment 1 and 0, 4, 8, 12, 16, 24 µg/mL (with and without activation) in Experiment 2. The test substance was considered negative for chromosomal aberrations in human lymphocytes in vitro under the S9 metabolic activation and non-activation conditions of the assay. There was no indication of chromosomal ploidy changes in cultures exposed to the test substance in either the presence or absence of S9 mix. Mutant frequencies of all cultures treated with the test substance were within the acceptable range for background mutant frequencies. Under the conditions of the study, the test substance is not considered to be non-clastogenic to human lymphocytes with and without metabolic activation (Durward, 2001). Based on the results of the read across study, the test substance, C14 ADBAC, is considered to be non-clastogenic in mammlian cells with and without metabolic activation.

Study 3: A study was conducted to determine the in vitro genetic toxicity of the read across substance, C12-16 ADBAC (active ingredient: 81.09%), according to a method similar to US EPA OPPTS 870.5300, in compliance with GLP. The study was performed on the HGPRT locus in Chinese hamster ovary (CHO) cells at test substance concentrations ranging from 0 to100 µg/mL. Preliminary cytotoxicity test showed the test substance to be slightly more toxic without S9 metabolic activation than with activation. The test substance was completely toxic at 20 µg/mL and higher without activation and completely toxic at 40 µg/mL and higher with activation. Dose levels selected for the first trial of the mutation assays covered nontoxic and highly toxic doses. Two independent non-activation and S9 metabolic activation assays were performed. Mutant frequencies of all cultures treated with the test substance were within the acceptable range for background mutant frequencies (0 to 13.5 x 10-6 with S9 mix and 0 to 15 x 10-6 without S9 mix). Under study conditions, C12 -16 ADBAC was not considered to induce any forward mutations at the HGPRT locus in CHO cells with and without metabolic activation (Young, 1989). Based on the results of the read across substance study, the test substance, C14 ADBAC, is considered not to induce mutation in the mammalian cells with and without metabolic activation.

Justification for classification or non-classification

Based on the negative in vitro gentoxicity results from read across studies, it can be concluded that C14 ADBAC does not require classification for genotoxicity according to CLP criteria (Regulation EC 1272/2008).