Dibutyl ether

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Remarks:

Standard Guideline study according to GLP: The test has been performed according to the old OECD TG 471 (1983) requiring the four Salmonella typhimurium strains used. The adopted OECD TG 471 (1997) requires the additional use of E. coli WP2 strains or Salmonella thyphimurium TA102 to detect certain oxidising mutagens, cross-linking agents and hydrazines. However, dibutyl ether is not a highly reactive agent and is therefore not expected to be a cross-linking agent, has no oxidising properties and is no hydrazine. Thus a GLP test according to OECD TG 471 (1983) without E. coli WP2 strains or Salmonella typhimurium TA102 is considered as sufficient to evaluate the mutagenic activity of dibutyl ether in this bacterial test system.

Data source

Reference

Reference Type:

publication

Title:

Salmonella mutagenicity test: V. Results from testing of 311 chemicals

Author:

Zeiger, E., Anderson, B., Haworth, S., Lawlor, T., Mortelmans, K.

Year:

1992

Bibliographic source:

Environ. Molecular Mutagen., 19, Suppl. 21, 2-141

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

Principles of method if other than guideline:

Method: other: according to Haworth et al. (1983) with minor variations

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyl ether

EC Number:

205-575-3

EC Name:

Dibutyl ether

Cas Number:

142-96-1

Molecular formula:

C8H18O

IUPAC Name:

1-butoxybutane

Details on test material:

dibutyl ether (purity > 99 %)

Method

Target gene:

not applicable

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Details on mammalian cell type (if applicable):

no data

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

3.3-667 µg/plate

Vehicle / solvent:

95% ethanol

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: sodium azide, 9-aminoacridine, 4-nitro-o-phenylenediamine, 2-aminoanthracene

Details on test system and experimental conditions:

The Ames test was performed as preincubation test in the absence of exogenous metabolic activation and in the presence of liver S-9 fractions of Aroclor 1254-induced male Sprague-Dawley rats and male Syrian hamsters. An initial toxicity assay to determine the appropriate concentration range for the mutagenicity assay was run. Toxic concentrations were defined as those that produced a decrease in the number of the his+ colonies, or a clearing in the density of the background lawn, or both. In the mutagenicity assay 5 concentrations per test variation were tested in triplicate, and repeat experiments were performed at least one weak following the initial trial. Concurrent solvent (95% ethanol) and positive controls were run with each trial. Positive control substances were in the trials without metabolic activation sodium azide for TA1535 and TA100, 9-aminoacridine for TA97, and 4-nitro-o-phenylenediamine for TA98, and in the trials with metabolic activation 2-aminoanthracene for all strains.

Evaluation criteria:

A chemical was designated nonmutagenic only after it had been tested in all strains without activation, and with 10% and 30% rat and hamster S-9. A chemical was judged mutagenic or weakly mutagenic if it produced a reproducible, dose-related response over the solvent control, under a single metabolic activation condition, in replicate trials.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

E. coli WP2 uvr A

Remarks:

The adopted OECD TG 471 (1997) requires the additional use of E. coli WP2 strains or Salmonella thyphimurium TA102 to detect certain oxidising mutagens, cross-linking agents and hydrazines. However, dibutyl ether is not a highly reactive agent and is ther

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Untreated negative controls validity:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

not applicable

Test results 2

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: >/= 100 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: >/= 100 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: >/= 100 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: >/= 100 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

No test was conducted with E. Coli WP2

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative

Dibutyl ether did not produce an dose-dependent increase of the number of his+ revertants/plate in the Salmonella typhimurium strains used neither in the absence nor in the presence of a metabolic activation system. Dose selection appears to be in a suitable range, because a bacteriotoxic effect was observed at the highest dose or the two highest doses tested (without metabolic activation 100 and/or 200 µg/plate with all strains; with metabolic activation depending on bacterial strain, kind and amount of liver S-9 fractions 100, 333, 334, 666 and/or 667 µg/plate). In each test well proven positive controls produced mutagenic effects demonstrating the functionally of the test system.

Executive summary:

In this study, the Ames test was performed as preincubation test in the absence of exogenous metabolic activation and in the presence of liver S-9 fractions of Aroclor 1254-induced male Sprague-Dawley rats and male Syrian hamsters. An initial toxicity assay to determine the appropriate concentration range for the mutagenicity assay was run. Toxic concentrations were defined as those that produced a decrease in the number of the his+ colonies, or a clearing in the density of the background lawn, or both. In the mutagenicity assay 5 concentrations per test variation were tested in triplicate, and repeat experiments were performed at least one weak following the initial trial. Concurrent solvent (95% ethanol) and positive controls were run with each trial. Positive control substances were in the trials without metabolic activation sodium azide for TA1535 and TA100, 9-aminoacridine for TA97, and 4-nitro-o-phenylenediamine for TA98, and in the trials with metabolic activation 2-aminoanthracene for all strains.

 

Dibutyl ether did not produce an dose-dependent increase of the number of his+ revertants/plate in the Salmonella typhimurium strains used neither in the absence nor in the presence of a metabolic activation system. Dose selection appears to be in a suitable range, because a bacteriotoxic effect was observed at the highest dose or the two highest doses tested (without metabolic activation 100 and/or 200 µg/plate with all strains; with metabolic activation depending on bacterial strain, kind and amount of liver S-9 fractions 100, 333, 334, 666 and/or 667 µg/plate). In each test well proven positive controls produced mutagenic effects demonstrating the functionally of the test system