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The mutagenic potential of the read-across substance C12-16 ADBAC was investigated in an Ames test usingSalmonella typhimuriumstrains TA1535, TA1537, TA102, TA98 and TA100. 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. The test substance was found to be non-mutagenic under the conditions of this study (Thompson PW, 2001).

C12-16 ADBAC was examined for mutagenic activity in another Ames test using the histidine-requiringS. typhimurium mutant strains TA 1535, TA 1537, TA 1538, TA 98 and TA 100, and a liver microsome fraction of Aroclor-induced rats for metabolic activation (S9-mix). The substance was tested at doses of 0, 0.31, 0.93, 2.78, 8.33 and 25 µg/plate. Based on preliminary toxicity test in TA 98, 25 µg/plate was chosen as the highest dose level. The test was carried out twice. The substance was considered to be non-mutagenic in the presence and absence of exogenous metabolic activation (Wilmer JWGM and Vogel N, 1986).

A guideline equivalent study was conducted to evaluate the potential of C12-16 ADBAC to induce mutations at the HGPRT locus in Chinese hamster ovary (CHO) cells. After a preliminary toxicity test, 0, 5, 10, 12.5, 15, 17.5 and 20 nL/mL (without metabolic activation) and 0, 15, 30, 45, 60, 75 and 90 nL/mL (with metabolic activation) were selected for the experiment. The entire experiment was repeated to confirm the results of the first experiment. Five hour exposure was used both with and without S9-mix. The test substance did not induce dose-related increase in the mutant frequency at the HGPRT locus at any dose level, either with or without metabolic activation. Exposure to the highest concentrations tested resulted in significant (initial) toxicity for the CHO cells; this indicates that the test was carried out with appropriate concentrations of the test substance. Exposure to positive control substances gave the expected increases in the mutation frequency. The toxicity of the test substance for CHO cells was clearly reduced in the presence of metabolic activation. Under the study conditions, test substance did not show mutagenic activity at the HGPRT locus in CHO cells (Davis PB, 1986).

A study was conducted to determine the mutagenic potential of C12-16 ADBAC at the HGPRT locus in Chinese hamster ovary (CHO) according to a method comparable to OPPTS 870.5300. A preliminary cytotoxicity test showed the test substance to be slightly more toxic without S9 metabolic activation than with activation. The test substance was toxic at 20 µg/mL and higher without activation and toxic at 40 µg/mL and higher with activation. Dose levels selected for the first trial of the mutation assays covered non-toxic 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 10-6with S9 mix and 0 to 15 x 10-6without S9 mix). Based on the results, C12-16 ADBAC was not found to induce any forward mutations at the HGPRT locus in CHO cells under the S9 metabolic activation and non-activation conditions of the assay (Young RR, 1989).

A guideline compliant study was conducted to determine the genotoxic potential of C12-16 ADBAC by the induction of chromosomal aberrations 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. In experiment 1, a 4 hour exposure with and without metabolic activation was followed by a 20 hour expression period. In experiment 2, the 4 hour exposure with metabolic activation was repeated while in the absence of metabolic activation the exposure time was increased to 24 hours. 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 lymphocytesin vitrounder 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 test conditions, C12-16 ADBAC was found to be non-clastogenic to human lymphocytesin vitro(Durward R, 2001).

A guideline study was conducted to determine the clastogenic potential of C12-16 ADBAC in Chinese hamster ovary cells. After a preliminary cytotoxicity test, 0, 0, 36, 1, 09, 3, 27 and 9.80 µg/mL (without S9-mix) and 0, 6.13, 12.25, 24.5, 49.0 and 98.0 µg/mL (with S9-mix) of the test substance were selected for the study. Exposure times were 21 hours for the experiments without metabolic activation and 3 hours for the experiments with metabolic activation, with harvesting times of 12 and 21 hours, respectively. The preliminary toxicity test showed that in the absence of S9-mix, the substance was toxic in concentrations of 15.68 µg/mL and above; in the presence of S9-mix, the substance was very toxic at 78.4 µg/mL and above at both harvesting times. Test substance did not induce a statistically significant increase in the number of cells with structural chromosome aberrations (breaks, exchanges and multiple aberrations) at any of the concentrations used, either in the absence or in the presence of the S-9 mix. Under the experimental conditions, C12-16 ADBAC was not clastogenic in CHO cells with or without metabolic activation (Wilmer JWGM and Vogel N, 1986).


Justification for selection of genetic toxicity endpoint
No study was selected, since all the available in vitro studies conducted with structurally similar substance were negative

Short description of key information:
The read-across substance C12-16 ADBAC was not mutagenic in bacterial reverse mutation assays or in the HGPRT locus in Chinese hamster ovary cells, either in the presence or absence of metabolic activation. The number of chromosomal aberrations was not increased by C12-16 ADBAC in the Chinese hamster ovary cells or human lymphocytes. Based on the above information and the read-across approach, C12-14 ADBAC is expected to be non-genotoxic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available data for the read-across substance C12-16 ADBAC, no classification is required for genotoxicity of C12-14 ADBAC according to DSD (67/548/EEC) and CLP (EC 1272/2008) criteria.