reaction mass of 2,2,4,6,6-pentamethylheptane-4-thiol, 2,3,4,6,6-pentamethylheptane-3-thiol , 2,4,4,6,6-pentamethylheptane-2-thiol, 2,3,4,6,6-pentamethylheptane-2-thiol

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

Study period:

May, 27, 1988-July 1, 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with restrictions (analytical purity not reported; only 4 strains tested)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

analytical purity not reported; only 4 strains tested

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

2,2,4,6,6-pentamethylheptane-4-thiol

EC Number:

296-714-7

EC Name:

2,2,4,6,6-pentamethylheptane-4-thiol

Cas Number:

93002-38-1

Molecular formula:

C12H26S

IUPAC Name:

2,2,4,6,6-pentamethylheptane-4-thiol

Details on test material:

- Name of test material (as cited in study report): TDM (tertiar dodecylmercaptan)
- Physical state: clear colourless liquid
- Analytical purity: not reported
- Lot/batch No.: 27051988
- Storage condition of test material: at room temperature

Method

Target gene:

his operon

Species / strain

Species / strain / cell type:

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

Additional strain / cell type characteristics:

other: The strains are deep rough (i.e. partly deficient in lipopolysaccharide side chains of their cell walls) and UV repair ability is reduced.

Metabolic activation:

with and without

Metabolic activation system:

Mammalian metabolism is simulated by S9 mix, which is obtained from livers of at least six adult male Sprague Dawley rats, treated with Aroclor 1254 (500 mg/kg body weight, 5 days before the sacrifice) together with cofactors.

Test concentrations with justification for top dose:

The following doses were evaluated in the first test:
1. Negative control 0 µg/plate;
2. TDM 12500 µg/plate;
3. TDM 2500 µg/plate;
4. TDM 500 µg/plate;
5. TDM 100 µg/plate;
6. TDM 20 µg/plate.

Doses 3 to 6 were produced by progressively diluting the highest dose (2) at 1:5 with the solvent.
Due to the substance´s toxicity the doses chosen for the repeated tests ranged from 300 µg to 9600 µg per plate.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: ethanol for TDM; DMSO for positive controls

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

Migrated to IUCLID6: -S9, tested at 10 µg/plate; only TA 1535

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: nitrofurantoin (-S9, tested at 0.2 µg/plate; only TA100)

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-1,2-phenylene diamine (-S9, tested at 10 µg/plate, only TA 1537)

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-1,2-phenylene diamine (-S9, tested at 0.5 µg/plate, only TA 98)

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (+S9, tested at 3 µg/plate, all strains)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hours
- Selection time (if incubation with a selection agent): 48 hours

SELECTION AGENT (mutation assays): L-histidine

DETERMINATION OF CYTOTOXICITY
- Method: The toxicity of the substance was assessed in 3 ways. First, the background growth on the plates for the mutant determination was grossly appraised. Secondly, a toxic effect of the substance was assumed when the mutant count per plate was clearly lower than a negative control count in dose correlation. Thirdly, the titer was determined.

Evaluation criteria:

A reproducible and dose-related increase in mutant counts for at least one strain is considered positive. For TA 1535, TA 100, and TA 98 in principle a twofold increase compared to the corresponding negative controls should be reached, whereas for TA 1537 at least a threefold increase should be reached. Otherwise, the result is evaluated as negative.

Results and discussion

Test results

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:

There was an indication of a bacteriotoxic effect of TDM at all doses. The total bacteria counts consistently produced results smaller than the negative controls. In addition, an inhibition of growth was noted.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Any other information on results incl. tables

Maximum number of revertants (means ± SD):

Trial 1 (20 - 12500 µg/plate)
	Control		Test Substance (µg/plate)
Strain	-S9	+S9	-S9	+S9
TA1535	10	19	10 (2500)	16 (20)
TA100	53	79	57 (20)	74 (20)
TA1537	8	6	7 (100)	6 (20)
TA98	24	29	19 (100)	35 (2500)
Trial 2 ( 0- 9600 µg/plate)
TA1535	13	17	12 (300)	15 (300)
TA100	79	78	65 (300)	63 (600)
TA1537	8	8	8 (300; 9600)	6 (600, 2400)
TA98	16	34	22 (600)	32 (9600)

 

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative