Amides, C8-18 (even numbered) and C18-unsatd., N-(hydroxyethyl)

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:

February 17, 2014 to March 7, 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Amides, C8-18 (even numbered) and C18-unsatd., N-(hydroxyethyl)

EC Number:

931-330-1

Cas Number:

69227-24-3

Molecular formula:

The alkyl chain length of the amide ranges between 8 and 18 carbon atoms

IUPAC Name:

Amides, C8-18 (even numbered) and C18-unsatd., N-(hydroxyethyl)

Test material form:

solid: flakes

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:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Rat liver microsomal enzymes (S9 homogenate)

Test concentrations with justification for top dose:

Range finding test in strain TA100 and E.Coli WP2 uvrA with and without metabolic activation: Positive control; Solvent control; 3; 10; 33; 100; 333; 1000; 3330; 5000 ug/L

Experiment 1: Tester trains TA1535, TA1537, TA98 with and without metabolic activation: Positive control; Solvent control; 3; 10; 33; 100; 333; 1000 ug/L.

Experiment 2: Tester trains TA1535, TA1537, TA98, TA100: Positive control; Solvent control; 3; 10; 33; 100; 333; 1000 ug/L. Tester strain E.Coli WP2 uvrA: Positive control; Solvent control; 3; 10; 33; 100; 333; 1000; 3330 and 5000 ug/L

Vehicle / solvent:

Ethanol

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

Ethanol

Controls 2

Negative solvent / vehicle controls:

yes

Remarks:

Saline

Positive controls:

yes

Remarks:

without metabolic activation

Positive control substance:

sodium azide

Remarks:

TA1535; concentration/plate 5 µg

Controls 3

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Remarks:

without metabolic activation

Positive control substance:

other: ICR-191

Remarks:

TA1537; concentration/plate 2.5 µg

Controls 4

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Remarks:

without metabolic activation

Positive control substance:

2-nitrofluorene

Remarks:

TA98; concentration/plate 10 µg

Controls 5

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Remarks:

without metabolic activation

Positive control substance:

methylmethanesulfonate

Remarks:

TA100; concentration/plate 650 µg

Controls 6

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Remarks:

without metabolic activation

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

WP2 uvrA; concentration/plate 15 µg

Controls 7

Positive controls:

yes

Remarks:

with metabolic activation and solvent DMSO

Positive control substance:

other: 2-aminoanthracene

Remarks:

TA1535 2.5 µg S9-mix 5 and 10%; TA1537 2.5 µg S9-mix 5%; TA1537 5 µg S9-mix 10%; TA98 1 µg S9-mix 5 and10%; TA100 1 µg S9-mix 5% ; TA100 2 µg S9-mix 10% ; W2P uvrA 15 µg S9-mix 5 and 10%

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium; in agar (plate incorporation)
NUMBER OF REPLICATIONS: Triplicates
DETERMINATION OF CYTOTOXICITY: Reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies were examined.

Evaluation criteria:

A Salmonella typhimurium reverse mutation assay and/or Escherichia coli reverse mutation assay is considered acceptable if it meets the following criteria:

a)The negative control data (number of spontaneous revertants per plate) should be within the laboratory historical range for each tester strain

b)The positive control chemicals should produce responses in all tester strains, which are within the laboratory historical range documented for each positive control substance. Furthermore, the mean plate count should be at least three times the concurrent vehicle control group mean
c)The selected dose range should include a clearly toxic concentration or should exhibit limited solubility as demonstrated by the preliminary toxicity range-finding test or should extendto 5 mg/plate.

No formal hypothesis testing was done.

A test substance is considered negative (not mutagenic) in the test if:

a)The total number of revertants in tester strain TA100 is not greater than two (2) times the concurrent control, and the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2 uvrA is not greater than three (3) times the concurrent vehicle control.

b)The negative response should be reproducible in at least one independently repeated experiment.


A test substance is considered positive (mutagenic) in the test if:

a)The total number of revertants in tester strain TA100 is greater than two (2) times the concurrent control, or the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2 uvrA is greater than three (3) times the concurrent vehicle control.

b)In case a repeat experiment is performed when a positive response is observed in one of the tester strains, the positive response should be reproducible in at least one independently repeated experiment.

The preceding criteria were not absolute and other modifying factors might enter into the final evaluation decision.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

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: Cytotoxicity, as evidenced by a decrease in the number of revertants, was observed in tester strain TA98 in the presence of 5 and 10 %(v/v) S9-mix.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Dose range finding test/Experiment 1

The test substance was tested in the tester strains TA100 and WP2 uvrA with concentrations of 3, 10, 33, 100, 333, 1000, 3330 and 5000 µg/plate in the absence and presence of S9-mix. Based on the results of the dose range finding test, the test substance was tested in the first mutation assay at a concentration range of 3 to 666 µg/plate in the absence of S9-mix and at a concentration range of 10 to 1000 µg/plate in the presence of 5% (v/v) S9-mix in the tester strains TA1535, TA1537 and TA98.

Precipitate

Dose range finding test: Precipitation of the test substance on the plates was observed at the start and at the end of the incubation period at concentrations of 3330 and 5000 µg/plate. First mutation experiment: Precipitation of the test substance on the plates was observed at the start of the incubation period at concentrations of 666 and 1000 µg/plate and no precipitate was observed at the end of the incubation period. Except in tester strain TA98 where no precipitate was observed at the start or at the end of the incubation period.

Toxicity

To determine the toxicity of the test substance, the reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies were examined.   In tester strain WP2 uvrA, the bacterial background lawn was not reduced at any of the concentrations tested. No biologically relevant decrease in the number of revertants was observed up to the dose level of 3330 μg/plate. Since the test substance precipitated heavily on the plates at the test substance concentration of 5000 μg/plate, the number of revertants of this dose level could not be determined. The reduction of the bacterial background lawn and the reduction in the number of revertants in the other tester strains are presented in Table 1.

Table1: Toxicity of Amides, C8-18(even numbered) and C18 unsatd., N-(hydroxyethyl) in the dose range finding/first experiment

(Reduction of the bacterial background lawn and in the number of revertant colonies)

Strain	Without S9-mix		With S9-mix
Dose          Bacterial              Revertant                 (μg/plate)    background lawn  colonies			Dose       Bacterial                Revertant (µg/plate) background lawn  colonies
TA1535		333          moderate                  -^2 666          extreme          microcolonies	333          slight                         -^1  666          slight                         -^2 1000        moderate                   -^2
TA1537		333          moderate                  -^1 666          extreme          microcolonies	333          slight                         -^1  666          slight                         -^2 1000        moderate             extreme
TA98		666           normal               extreme	1000         normal                       -^2
TA100		333         slight                 moderate 1000         extreme          microcolonies 3330         absent              complete 5000         absent                      -^3	1000         moderate          extreme 3330         absent             complete 5000         absent                      -^3

-¹  No reduction in the number of revertant colonies

-²  Reduction in the number of revertant colonies, but not less than the minimal value of the historical control data range.

-³  Due to the amount of precipitate no colony determination was possible

Experiment 2

To obtain more information about the possible mutagenicity of the test substance, a second mutation experiment was performed in the absence of S9-mix and in the presence of 10% (v/v) S9-mix. Based on the results of the first mutation assay, the following dose range was selected for the second mutation assay: TA1535, TA1537, TA98, TA100: Without S9-mix: 3, 10, 33, 100, 333 and 666 μg/plate and with S9-mix: 10, 33, 100, 333, and 1000 μg/plate WP2 uvrA: Without and with S9-mix: 10, 33, 100, 333, 1000 and 3300 µg/plate.

Precipitate

Precipitation of the test substance on the plates was only observed in tester strain WP2 uvrA at the start of the incubation period at concentrations of 1000 and 3330 µg/plate in the absence of S9-mix and at 3330 µg/plate in the presence of S9-mix. At the end of the incubation period, precipitation on the plates was only observed at 3330 µg/plate in the absence of S9-mix.

Toxicity

In tester strain WP2 uvrA, no reduction of the bacterial background lawn and no biologically relevant decrease in the number of revertants were observed. The reduction of the bacterial background lawn and the reduction in the number of revertants in the other tester strains is presented in Table 2.

Table2: Toxicity of the test substance in second experiment (Reduction of the bacterial background lawn and in the number of revertant colonies)

Strain	Without S9-mix		With S9-mix
Dose          Bacterial              Revertant                 (μg/plate)    background lawn  colonies			Dose       Bacterial                Revertant (µg/plate) background lawn  colonies
TA1535		333          moderate                  -^2 666          extreme             absent	1000        moderate                   -^1
TA1537		333          slight                  moderate 666          extreme           microcolonies	1000        normal                       -^2
TA98		666           moderate          extreme	1000         normal             moderate
TA100		100          slight                 moderate  333         moderate           extreme 1000         extreme          microcolonies	333         normal             moderate  666         moderate         extreme 1000         moderate         extreme

-¹  No reduction in the number of revertant colonies

-²  Reduction in the number of revertant colonies, but not less than the minimal value of the historical control data range.

Experiment 3

In the first experiment in tester strain TA98 and in the second experiment in the tester strains TA1537 and WP2 uvrA no toxicity or precipitate on the plates was observed in the presence of S9-mix. Therefore a third mutation experiment was performed with these strains and tester strain TA98 in the presence of S9-mix at a concentration range of 333 to 5000 µg/plate.

Precipitate

Precipitation of the test substance on the plates was observed at the start and at the end of the incubation period at concentrations of 3330 and 5000 µg/plate.

Toxicity

Due to precipitate of the test substance on the plates the bacterial background could not be determined at the dose levels of 3330 and 5000 μg/plate, except at tester strain WP2 uvrA. Cytotoxicity, as evidenced by a decrease in the number of revertants, was observed in tester strain TA98 in the presence of 5 and 10 %(v/v) S9-mix. Mutagenicity In the third mutation assay, no increase in the number of revertants was observed upon treatment with the test substance under all conditions tested.

Applicant's summary and conclusion

Conclusions:

Under the study conditions, the test substance was not mutagenic in the Salmonella typhimurium and Escherichia coli reverse mutation assay.

Executive summary:

A study was conducted to evaluate the in vitro genetic toxicity of the test substance, C8-18 and C18-unsatd. MEA, according to OECD Guideline 471, in compliance with GLP. The substance was tested in the Salmonella typhimurium reverse mutation assay with four histidine-requiring strains of Salmonella typhimurium (TA1535, TA1537, TA98 and TA100) and in the Escherichia coli reverse mutation assay with a tryptophan-requiring strain of Escherichia coli (WP2 uvrA). The test was performed in two independent experiments in the presence and absence of S9-mix (rat liver S9-mix induced by Aroclor). An additional experiment was performed with the strains TA1537, TA98 and WP2 uvrA in the presence of S9-mix. In the dose range finding test, the substance was tested up to concentrations of 5000 μg/plate in the absence and presence of S9-mix in the strains TA100 and WP2 uvrA. The substance precipitated on the plates at dose levels of 3330 and 5000 μg/plate. In tester strain TA100, toxicity was observed at dose levels of 333 μg/plate and upwards in the absence of S9-mix and at dose levels of 1000 μg/plate and upwards in the presence of S9-mix. In tester strain WP2 uvrA, the bacterial background lawn was not reduced at any of the concentrations tested. No biologically relevant decrease in the number of revertants was observed up to the dose level of 3330 μg/plate. Since the test substance precipitated heavily on the plates at the test substance concentration of 5000 μg/plate, the number of revertant colonies of this dose level could not be determined. Based on the results of the dose range finding test, the substance was tested in the first mutation assay at a concentration range of 3 to 666 μg/plate in the absence of S9-mix and at a concentration range of 10 to 1000 μg/plate in the presence of 5% (v/v) S9-mix in tester strains TA1535, TA1537 and TA98. The test substance did not precipitate on the plates at this dose level. Toxicity was observed in all tester strains, except in TA98 in the presence of S9-mix. In an independent repeat of the assay with additional parameters, the substance was tested at a concentration range of 3 to 666 μg/plate in the absence of S9-mix and at a concentration range of 10 to 1000 μg/plate in the presence of 10% (v/v) S9-mix in tester strains TA1535, TA1537, TA98 and TA100 and at 10 to 3330 μg/plate in tester strain WP2 uvrA in the absence and presence of 10% (v/v) S9-mix. Precipitate on the plates was only observed at the dose level of 3330 μg/plate in the absence of S9-mix. Toxicity was observed in all tester strains, except in TA1537 and TA98 in the presence of S9-mix and in WP2 uvrA in the absence and presence of S9-mix. Since in the first experiment in tester strain TA98 and in the second experiment in the tester strains TA1537, TA98 and WP2 uvrA no toxicity or precipitate on the plates was observed, a third mutation experiment was performed with these strains in the presence of S9-mix (5% %(v/v) S9-mix and 10 %(v/v) S9-mix, for experiment 1 and 2, respectively). The substance was tested up to 5000 μg/plate. The test substance precipitated on the plates at dose levels of 3330 and 5000 μg/plate. Due to the precipitate of the test substance on the plates the bacterial background could not be determined at the dose levels of 3330 and 5000 μg/plate, except at tester strain WP2 uvrA. Cytotoxicity, as evidenced by a decrease in the number of revertants, was observed in tester strain TA98 in the presence of 5 and 10 %(v/v) S9-mix. The substance did not induce a significant dose-related increase in the number of revertant (His+) colonies in each of the four tester strains (TA1535, TA1537, TA98 and TA100) and in the number of revertant (Trp+) colonies in tester strain WP2 uvrA both in the absence and presence of S9-metabolic activation. These results were confirmed in an independently repeated experiment. In this study, the negative and strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly. Under the study conditions, the test substance was not mutagenic in the Salmonella typhimurium and Escherichia coli reverse mutation assay (Verspeek-Rip, 2014).