1,1,3,3-tetramethylbutyl hydroperoxide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well-conducted study performed prior to GLP regulations. Documentation is less complete than current practice but sufficient for the study to be used and rated. Test method used is similar to current guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

1977

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

no

Remarks:

Study performed prior to GLP regulations

Type of assay:

bacterial forward mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

1,1,3,3-tetramethylbutyl hydroperoxide

EC Number:

227-369-2

EC Name:

1,1,3,3-tetramethylbutyl hydroperoxide

Cas Number:

5809-08-5

Molecular formula:

C8H18O2

IUPAC Name:

2,4,4-trimethylpentane-2-peroxol

Test material form:

other: clear, colorless liquid

Method

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S-9 induced with Aroclor 1245

Test concentrations with justification for top dose:

0, 0.8, 4, 20, 100, 500 µg/plate

Vehicle / solvent:

acetone

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

methylmethanesulfonate

other: N-methyl-N-nitro-N-nitrosoguanidine, 4-aminobiphenyl

Details on test system and experimental conditions:

The Salmonella typhimurillin mutants used in this study, viz. S. typh. TA 1535, TA 1531, TA 1538, TA 98 and TA 100, a gift or Dr. B.N. Ames, Berkeley,California, USA, are stored as frozen cultures at - 80 °C. To obtain fresh cultures for mutagenesis testing, nutrient broth is inoculated with the frozen culture and grown up overnight with shaking at 37 °C. The reversion properties of each strain are regularly checked, using the mutagens: MMS; MNNG; 9-AA and 4-ABP. In addition, the strains are checked for histidine requirement, for sensitivity to crystal violet, deoxycholate and for resistance to ampicillin.

The procedures used in this mutagenic assay are described in detail by Ames et al. (1975). Briefly, the procedure was as follows: to 2.5 ml molten soft agar vere added 0.1 ml of a fully grown culture of one of the tester strains, 0.1 ml of an appropriate dilution/suspension of the test compound and the liver microsome system if indicated. The ingredients were thoroughly mixed and immediately poured onto minimal glucose agar plates. After the top agar had been allowed to harden, the plates vere incubated at 37 °C for three days. Then the colonies (revertants vhich are histidine-independent) were counted, and the background lawn of bacterial growth examined. Based on the results of preliminary toxicity tests, the test materials were examined at levels up to 1000 µg/plate except for TMPH which was tested at levels up to 500 µg/plate. All determinations were carried out in triplicate and appropriate controls were included in each assay.

Results and discussion

Test results

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 100 and 500 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

not specified

Additional information on results:

Background lawn of bacterial growth less dense than in control plates.

Remarks on result:

other: all strains/cell types tested

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with and without metabolic activation

Not mutagenic

Executive summary:

The mutagenic activity of THPH was examined in the Salmonella/ microsome mutagenicity test, using a set of five histidine requiring mutants of Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 98 and TA 100) and liver homogenate of Aroclor induced rats.

Incorporation of TMPH up to non-inhibitory levels did not induce an increase of the reversion rate to his+ prototrophy with any of the five tester strains. At higher levels, chemical toxicity interfered with the mutagenicity testing. It was concluded that the present results did not reveal any mutagenic activity of TMPH in the Salmonella/microsome mutagenicity test.