Dimethyl(octyl)amine

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

The study was performed according to the AMES test methodologies but predated the current OECD 471 guideline

Principles of method if other than guideline:

This report describes experiments performed to assess the mutagenic activity of Farmin DM08P in two histidine-dependent strains of Salmonella typhimurium using the procedures developed by Ames et al (1975) and later refined by Maron and Ames (1983).

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Dimethyl(octyl)amine

EC Number:

230-939-3

EC Name:

Dimethyl(octyl)amine

Cas Number:

7378-99-6

Molecular formula:

C10H23N

IUPAC Name:

dimethyl(octyl)amine

Details on test material:

Name: AD 1
Chemical Name: N, N-Dimethyloctylamine
CAS No.: 7378-99-6
Batch No.: 13602808
Expiry Date: not applicable
Physical State at Room Temperature: liquid
Colour: clear
Volatility: volatile
Density: 0.765
Molecular Weight: 157.3
Active Components: > 95%
Structure Formula of
Active Component: C8H17-N-(CH3)2
Storage Conditions: at room temperature

Specific details on test material used for the study:

300 g sample of Fannin DM08P, of lot No. 1318, a clear courless liquid, was received from Kao Corporation on 21 November 1995. It was stored at ambient temperature until required.

Method

Target gene:

rfa wall mutation, uvrB and pKM101 in Salmonella typhimurium. Tester strains TA98, TA100,

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 98

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 100

Metabolic activation:

with and without

Metabolic activation system:

Young male CD rats, ca. 200 g BW, were obtained from Charles River Breeding Laboratories (U.K.), Margate, Kent. Aroclor 1254 (500 mg/kg bodyweight in corn oil) was administered as a single intraperitoneal injection to induce microsomal enzyme activity.

Test concentrations with justification for top dose:

The maximum concentration of test material employed was selected with the aid of a preliminary toxicity test with strain TA 98.
Visible thinning of the background lawn ofnon-revertant cells was obtained following exposure to the test item at 5000 μg per plate only. This wastherefore selected as the top exposure level for use in the main tests.
Maximum dose to be plated in the presence of metabolic activation =5,000 ug per plate for both TA98 and TA100.

Vehicle / solvent:

ethanol

Controls

Untreated negative controls:

yes

Remarks:

negative control plates confirmed the characteristically low spontaneous reversion rates of the tester strains

Negative solvent / vehicle controls:

yes

Remarks:

absence of effects of spontaneous reversionon rates when ethanol included

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

2-nitrofluorene

sodium azide

benzo(a)pyrene

Details on test system and experimental conditions:

A solution of Farmin DM08P was prepared in ethanol at 50 mg/ml, and four half-log dilutions were prepared from this solution. Aliquots (0.1 ml) of each concentration of Farmin DM08P were placed in sterile tubes. Molten, histidine-deficient top-agar (2 ml), maintained at 45°C, and bacterial culture (0.1 ml) were then added. The tubes were mixed by inversion and 0.5 ml rat liver microsomal preparation (S-9 mix) or O.IM phosphate buffer was added where appropriate. The tubes were again inverted to mix thoroughly and the contents poured onto plates containing solidified minimal medium (20 ml).
Further plates were prepared without the inclusion of the test organisms to verify the sterility of the S-9 mix and the test material. A control series of plates was prepared to confirm the inability of ethanol (0.1 ml) to induce reversion in the bacterial strains, and to provide a measure of the spontaneous mutation rates. Aliquots (0.1 ml) of a 10^·6 dilution of the overnight cultures were spread on
the surface of plates of complete medium to measure the viability and celldensity of each culture. All plates were prepared in duplicate, allowed to solidify and incubated at 37°C for 2 days. After incubation, numbers ofrevertant colonies were counted, either manually or with an automated colony counter. Total colonies on nutrient plates were counted in the same way. Growth of the background lawn of non-revertant cells on minimal plates was verified.
All plates and tubes were identified by the use of numbers indelibly marked on the plates and test tube racks.

Evaluation criteria:

The plates were incubated at 3 7°C for 2 days and were then examined for the presence of a background lawn of non-revertant colonies; toxicity of the test material is shown by absence or thinning of the background lawn. The level oftest material chosen as the top level for pour-plate tests is normally the lowest level causing visible thinning of the lawn. (In the absence of such thinning, a top level of 5 mg/plate would be selected).

Statistics:

For all replicate platings, the mean number of revertants per plate was calculated

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

The test material, Farmin DM08P, did not exhibit any mutagenic activity under the conditions of test.

Executive summary:

The material Farmin DM08P was examined for mutagenic activity in two histidinedependent auxotrophs of Salmonella typhimurium, strains TA 98 and TA 100, using pour-plate assays.

The studies, which were conducted in the presence and absence of an activating system derived from rat liver (S-9 mix), employed a range of levels of Farmin DM08P from 50 to 5000 μg per plate, selected following a preliminary toxicity test in strain TA 98. The tests included solvent (ethanol) controls with and without S-9 mix.

No increases in reversion to prototrophy were obtained with either of the bacterial strains at the Farmin DM08P levels tested, either in the presence or absence of S-9 mix.

Inhibition of bacterial growth, observed as slight thinning of the background lawn of non-revertant cells and reduction in revertant colony numbers, occurred in both strains following exposure to Farmin DM08P at 5000 μg per plate.

Marked increases in the number of revertant colonies were induced by the known mutagens benzo[a]pyrene, 2-nitrofluorene and sodium azide when examined under similar conditions.

It was concluded that Farmin DM08P did not exhibit any mutagenic activity under the conditions of test.