N-butyl acetate

Endpoint summary

Additional information

Mutagenic activity of n-butyl acetate (purity: 99.6%) was investigated in a bacterial reverse gene mutation assay according to Ames (1975), which was selected as key study. The test was performed using Salmonella typhimurium strains TA 1535, TA 1537, TA98, TA1538 and TA100 as well as Escherichia coli strain WP2uvrA with (polychlorinated biphenyl (KC 500) induced rat liver S9 mix) and without metabolic activation at substance concentrations of 0, 1, 5, 10, 50, 100, 500, 1000 and 5000 µg/plate using the preincubation method. The test item did not reveal any mutagenic activity under the conditions tested. The appropriate reference mutagens showed distinct positive mutagenic effects (Shimizu et al., 1985; RL2).

These findings of the key study were confirmed by several other studies:

In another AMES test, strains of S. typhimurium (TA 98, TA 100, TA 1535, TA 1537, TA 1538)  were exposed to n-butyl acetate at concentrations of 0.005, 0.01, 0.1, 1.0, 5.0, and 10.0 µl/plate (4.4, 8.83, 88.26, 441.3, 8826 µg/plate) in the presence and absence of mammalian metabolic activation (S9 mix from Aroclor 1254 induced rat liver) in a plate incorporation assay. N-butyl acetate did not increase the number of revertants in any of the test strains with or without metabolic activation (Jagannath, 1979; RL3; cf. IUCLID study record Celanese, 1979). Mutagenic activity of n-butyl acetate (purity: > 99%) was investigated in Salmonella typhimurium strains TA 1535, TA 1537, TA98, TA97 and TA100 with (Aroclor 1254-induced rat liver S9 mix or with Aroclor 1254-induced hamster liver S9 mix) and without metabolic activation at concentrations of 0, 33, 100, 333, 1000, 1666, 3333 and 10000 µg/plate using the preincubation method. The test item did not reveal any mutagenic activity under the conditions tested. The appropriate reference mutagens showed distinct positive mutagenic effects (Zeiger et al., 1992; RL3). Mutagenic activity of n-butyl acetate (purity: 99%) was investigated in S. typhimurium strains TA92, TA 94, TA 98, TA 100, TA 1535 and TA 1537 with (polychlorinated biphenyl (KC-400) induced rat liver S9 mix) and without metabolic activation at concentrations up to 10000 µg/plate using the preincubation method. The test item did not reveal any mutagenic activity under the conditions tested. According to the authors the appropriate reference mutagens showed distinct positive mutagenic effects (Ishidate et al., 1984 - Ames; RL3). Negative results with n-butyl acetate in the Ames Assay in the presence and absence of metabolic activation were also reported in a test for which only a summary report is available (Schöberl, 1988; RL4; cf. IUCLID study record Huels AG, 1988). In summary, all tests performed with n-butyl acetate in the reverse gene mutation assay in bacteria in the presence or absence of metabolic activation showed negative results indicating that n-butyl acetate is not mutagenic in the Ames Assay.

A gene mutation assay (HPRT test) was performed withbutan-1-ol in Chinese hamster lung fibroblasts (V79). The test item was dissolved in DMSO and added to the cell culture at concentration of 23.1, 46.3, 92.5, 185.0, 370.0 and 740.0 µg/mL in both experiments. Exposure duration was 4 h in the first experiment (in the presence and absence of a metabolic activating system) and 24 hours (in the absence of a metabolic activating system) or 4 hours (in the absence of a metabolic activating system) in the second experiment. No gene mutations at the HPRT locus in V79 cells were induced under the conditions tested (Harlan, 2010; RL2).

These results are supported by the finding that butan-1-ol did not induce relevant increases in TK mutations in a reliable mouse lymphoma assay (MLA) with L5178Y cells with or without metabolic activation in non-cytotoxic doses (6.25 and 5.0 µL/mL without and with metabolic activation, respectively; Celanese 1978, RL2).

For chromosomal aberration two studies are thought to be adequate to cover the endpoints requirements in a weight of evidence approach:

The potential of n-butyl acetate to induce chromosomal aberrations in vitro was investigated in Chinese hamster lung cells (CHL) which were exposed to up to 2000 µg n-butyl acetate (purity: 99%) /plate for 48 hours without metabolic activation. The test item did not induce polyploidy or structural aberrations under the conditions tested (Ishidate et al., 1984 – mammalian cells CA; WoE, RL3).

Butan-1-ol was evaluated in the in vitro mammalian cell micronucleus test (MNT) of its potential to induce chromosomal aberrations (Lasne et al. 1984, RL2). CHL V79 cells were treated with 50 µL/mL (=ca. 41 mg/mL) without metabolic activation and subsequently 4000 to 7000 cells were scored for micronuclei. Butan-1-ol did not cause an increase in micronuclei.

These findings are supported by an in vivo test for the induction of micronuclei performed in mice with the n-butyl acetate metabolite n-butanol: n-Butanol was tested for clastogenicity and for the ability to have spindle poison effects in NMRI mice using the micronucleus test method. For this purpose, the test substance, dissolved in olive oil, was administered once orally to male and female animals at dose levels of 500 mg/kg, 1000 mg/kg and 2000 mg/kg body weight in a volume of 10 mL/kg body weight in each case. Bone marrow of the animals was prepared 24 or 48 hours after administration of the test item. Single oral administration of n-butanol did not lead to any increase in the number of polychromatic erythrocytes containing either small or large micronuclei. The rate of micronuclei was always in the same range as that of the negative control in all dose groups and at all sacrifice intervals (Engelhardt and Hoffmann, 1998, cf. IUCLID study record BASF, 1998). Based on these data it is concluded that n-butyl acetate does not induce cytogenic effects in vitro and in vivo.

Induction of mitotic recombination in Saccharomyces cerevisiae (strain D61.M) was investigated with n-butyl acetate (purity at least 97%; test concentrations: 0.25, 0.32, 0.40%). The test item was not mutagenic in this assay, cytotoxicity was observed at all test concentrations, controls were in the normal range (Zimmermann et al., 1985; RL3).

As n-butyl acetate is rapidly and almost completely hydrolysed to butan-1-ol in vivo it seems to be scientifically justified to transfer the experimental findings with butan-1-ol on n-butyl acetate in a read across process (for further details see read-across report in IUCLID section 13). The negative findings with butan-1-ol in vitro (HPRT, MLA, MNT) and in vivo (MNT) are completely in line with the negative findings obtained with n-butyl acetate in several in vitro assays and support the conclusion that n-butyl acetate is not genotoxic and has not to be classified for genotoxicity.

Justification for selection of genetic toxicity endpoint
No study was selected since, all available data (covering the data requirements) were negative.

Short description of key information:
n-Butyl acetate is not mutagenic in the reverse bacterial mutation assay (Ames Assay) in the presence and absence of metabolic activation. n-Butyl acetate did not induce chromosomal aberrations in vitro. The n-butyl acetate metabolite butan-1-ol did not induce chromosomal aberrations in vitro or gene mutations at the HPRT locus of V79 cells in the presence or absence of a metabolic activating system nor did butan-1-ol induce micronuclei in mice in vivo at concentrations up to 2000 mg/kg n-butanol.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the negative results obtained in all tests for genotoxicity performed with n-butyl acetate in vitro and with its metabolite butan-1-ol in vivo and in vitro it is concluded that n-butyl acetate has not to be classified for genotoxicity according to Regulation (EC) No 1272/2008.