Di-tert-dodecyl disulphide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

26th May 1983 and revised Draft document of December 1994 .

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Di-tert-dodecyl disulphide

EC Number:

248-468-7

EC Name:

Di-tert-dodecyl disulphide

Cas Number:

27458-90-8

Molecular formula:

C22H46S2 to C24H50S2

IUPAC Name:

2-ethyl-5,6,6-trimethyl-1-[(3,5,6,6-tetramethylheptyl)disulfanyl]heptane; 2-ethyl-5,6,6-trimethyl-1-[(5,6,6-trimethylheptyl)disulfanyl]heptane; 3-ethyl-1-[(2-ethyl-5,6,6-trimethylheptyl)disulfanyl]-5,6,6-trimethylheptane

Test material form:

liquid

Method

Target gene:

Histidine operon

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

liver micrasomal fraction (S9) of rats induced with Araclor 1254

Test concentrations with justification for top dose:

312.5, 625, 1250, 2500 and 5000 µg/plate

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

mitomycin C

other: 2-Anthramine

Details on test system and experimental conditions:

To assess the toxicity of the test substance to the bacteria, six doses (one plate/dose) were tested in the TA 98, TA 100 and TA 102 strains, with or without S9 mix.

The tests were peïf ormed according to:
. direct plate incorporation method (both tests without S9 mix, first test with S9 mix): 0.05 to 0.1 ml of the test substance solution, 0.5 ml of S9 mix when required and 0.1 ml of the strain were mixed with 2 ml of overlay agar containing traces of the relevant amino-acid and biotin and maintained at 45°C. After rapid homogenization, the mixture was spread out on a Petri plate containing minimum medium.
. preincubation rnethod (second test with S9 mix): 0.05 to 0.1 ml of the test substance solution, 0.5 ml of S9 mix and 0.1 ml of the strain were incubated for 60 minutes at 37°C prior adding the overlay agar and pouring onto the surface of a minimum agar plate.
After 48 to 72 hours of incubation at 37°C, revertants were scored with an automatic counter (Artek counter, model 880, O.S.I., 75015 Paris, France).

Evaluation criteria:

Biological relevance of the results was considered first. In addition, the following criteria may be used as an aid for determining a positive response:
. a dose-related increase in the number of revertants,
and/or
. a reproducible increase in the number of revertants (i.e. a doubling in at least one strain when compared to that of the controls) for at least one of the doses.

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

DI-tert-DODECYL DISULFIDE did not show mutagenic activity in this bacterial reverse mutation assay on Salmonella typhimurium.

Executive summary:

The potential of DI-tert-DODECYL DISULFIDE to induce a reverse mutation was evaluated in bacteria Salmonella typhimurium. A preliminary toxicity test was performed to define the doses to be used for the mutagenicity study. The test substance was then tested in two independent tests, with or without a metabolic activation system, the S9 mix, prepared from a liver micrasomal fraction (S9) of rats induced with Araclor 1254. The tests were perf ormed according to the direct plate incorporation method except the second test with S9 mix, according to the preincubation method (one hour, 37°C). Five strains of bacteria Salmonella typhimurium: TA 1535, TA 1537, TA 98, TA 100 and TA 102 were used. Each strain was exposed to five doses of the test substance (three plates/dose). After 48 to 72 hours of incubation at 37°C, the revertant colonies were scored. DI-tert-DODECYL DISULFIDE was dissolved in dimethylsulfoxide (DMSO). The number of revertants of the vehicle and positive controls was as specified in the acceptance criteria and within the range of the historical data. The top dose was selected according to the criteria specified in the international regulations. Since the test substance was non-toxic, freely soluble, the top dose was 5000 µg/plate. The selected range dose was: 312.5, 625, 1250, 2500 and 5000 µg/plate. The test substance did not induce any significant increase in the number of revertants, with or without S9 mix, in any of the five strains. Under these experimental conditions, DI-tert-DODECYL DISULFIDE did not show mutagenic activity in this bacterial reverse mutation assay on Salmonella typhimurium.