N-butyl acetate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A mouse ear swelling test (MEST) was performed with n-butyl acetate in female CF-1 mice (at least 10 animals in the test group and 5 animals in the control group). Induction was performed with the pure test substance and challenge with a 50% dilution in 70% ethanol. The test item was not sensitising in this test (Gad et al., 1986).

A guinea pig maximization test (GPMT) was performed with n-butyl acetate in Hartley guinea pigs (15 animals in the test group and 6 animals in the control group; no information on sex). Intradermal induction was performed with a 50% solution of the test substance in ethanol. Topical induction and challenge were performed with the pure test item. n-Butyl acetate was not sensitising in this test (Gad et al., 1986).

A Buehler test was performed with n-butyl acetate in male and female Hartley guinea pigs (10 animals/dose group). The test item (test concentrations not presented) was not sensitising in this test (Gad et al., 1986).

Reports of the GPMT and Buehler test have been judged not to be reliable due to insufficient documentation of the study details and results (RL3). Data presentation of the MEST was sufficiently and reliable. But, the MEST is only a screening assay and a reliable MEST does not fulfill the information requirements of REACH. Therefore, this test was also judged not to be reliable and evaluation of the endpoint skin sensitisation is performed in a weight of evidence approach:

Concurrently, all available animal tests on skin sensitisation gave negative results. Additionally, negative results were obtained in a human repeated insult patch test with 50 individuals (nine 24-hour applications with 0.2 ml of the test substance over three weeks; challenge 10 to 14 days after the final induction application). None of the participants showed a sensitising reaction to n-butyl acetate (Gad et al., 1986; RL3). The study was judged not to be reliable (RL3) due to insufficient reporting. Three maximization tests in humans performed with n-butyl acetate or nail polish containing n-butyl acetate (~25%) also reported negative results for skin sensitisation (Anon., 1989; RL4). As these data were only available from secondary sources, reliability could not be assigned. A single case from a male worker in a pharmaceutical factory, who showed a positive reaction in a patch test with 5% n-butyl acetate in olive was reported (Roed-Petersen, 1980; RL3). This report was judged not to be reliable (RL3) due to insufficient reporting. Based on these primarily negative findings (from reliable animals studies and from human volunteer studies, with the exception of only one positive finding in a case study) it is concluded that n-butyl acetate has not to be classified as a skin sensitiser.

Migrated from Short description of key information:
Animal experiments (Gad et al., 1986; RL3; mouse, guinea pig) and investigations with humans (Gad et al., 1986; RL3; Roed-Petersen, 1980; RL3; Anon., 1989; RL4) revealed that n-butyl acetate is not sensitising to skin.

Justification for selection of skin sensitisation endpoint:
No single study was selected as endpoints conclusion was reached in a weighth-of-evidence approach based on the results obtained in various tests published by the same author (Klimisch score 3, due to minor details missing in reporting, but overall adequate to cover the endpoints requirements).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Migrated from Short description of key information:
There are no data on sensitization by inhalation.

Justification for classification or non-classification

n-Butyl acetate was not a skin sensitiser in a mouse ear swelling test, a guinea pig maximisation test, a Buehler test and in several investigations with humans. Therefore, n-butyl acetate has not to be classified according to Regulation (EC) No 1272/2008.

There are no data on sensitization by inhalation.