Reactionmass of octan-2-yl prop-2-enoate and octan-3-yl prop-2-enoate and octan-4-yl prop-2-enoate

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:

2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1997

Deviations:

no

Remarks:

No deviations ocurred that negatively impacted the integrity of the study.

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

1

Reference substance name:

Reactionmass of octan-2-yl prop-2-enoate and octan-3-yl prop-2-enoate and octan-4-yl prop-2-enoate

EC Number:

947-155-9

Molecular formula:

C11H20O2

IUPAC Name:

Reactionmass of octan-2-yl prop-2-enoate and octan-3-yl prop-2-enoate and octan-4-yl prop-2-enoate

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: 3M Company, Lot 11
- Purity, including information on contaminants, isomers, etc.: 99.7%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:
Kept in a room with controls set to maintain 19°C to 25°C

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing (e.g. warming, grinding):
The test article was suspended in 200 proof ethanol.

FORM AS APPLIED IN THE TEST (if different from that of starting material)
The test article was suspended in 200 proof ethanol.

Method

Target gene:

Tryptophan and histidine operons

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

The Aroclor 1254-induced rat liver S9 fraction (Lot No. 4048) was purchased from Molecular Toxicology, Inc. (Boone, NC). The metabolic activation mixture was prepared fresh on each day of testing and maintained on ice throughout the assay.
The S9 mixture (7.5% [v/v]) for metabolic activation consists of the following in a total volume of 10 mL:
0.75 mL of S9 fraction
0.20 mL of MgCl2 (0.4M) - KCl (1.65M)
0.05 mL of glucose-6-phosphate (1M)
0.40 mL of nicotinamide adenine dinucleotide phosphate (NADP) (0.1M)
5.00 mL of phosphate buffered saline
3.60 mL of sterile distilled deionized wate

Test concentrations with justification for top dose:

In the range-finding assay, MTDID 44428 was tested in single plates at 1, 5, 10, 50, 100, 500, 1000, and 5000 µg/plate with strains TA100 and WP2 uvrA using the plate incorporation method. Precipitates were not observed at any concentration in both strains with and without metabolic activation. Cytotoxicity (i.e., reduction in the background lawn and/or mean number of revertant colonies) was observed at ≥ 500 µg/plate in TA100 without metabolic activation and ≥ 1000 µg/plate in TA100 with metabolic activation.

In the mutagenicity assay, MTDID 44428 was tested 5, 10, 25, 50, 100, 250, 500, and 1000 µg/plate in strains TA1537, TA98, TA1535, and TA100, and 100, 250, 500, 1000, 2500, and 5000 µg/plate in strain WP2 uvrA, using the plate incorporation method.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: 200 proof ethanol

- Justification for choice of solvent/vehicle: Test article solubility and test system compatibility.

- Justification for percentage of solvent in the final culture medium: Per OECD 471 recommendation.

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

2-nitrofluorene

sodium azide

other: 2-aminoanthracene, ICR-191 Acridine

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: Triplicate
- Number of independent experiments : 2

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding (if applicable): 10^8 and 10^9 cells per mL of culture
- Test substance added in agar (plate incorporation)

TREATMENT AND HARVEST SCHEDULE:
- Preincubation period, if applicable: Stock cell solutions were incubated overnight prior to dosing to bring the cell density to the appropriate level needed for testing.
- Exposure duration/duration of treatment: 48 hours with the test article in agar.
- Harvest time after the end of treatment (sampling/recovery times): Plates were counted following a 48 hour exposure period.

FOR GENE MUTATION:
- Expression time (cells in growth medium between treatment and selection): 48 hours
- Selection time (if incubation with a selective agent): 48 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 48 hours
- Selective agent: Histidine and trypotophan-minimal agars.
- Number of cells seeded and method to enumerate numbers of viable and mutants cells: 10^8 and 10^9 cells per mL of culture

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method: Background growth inhibition

METHODS FOR MEASUREMENTS OF GENOTOXICIY :
The test substance was considered positive for mutagenicity if it induced an increase of revertants per plate with increasing concentration. The increases should be at least 2 times the vehicle control background frequency for strains with high spontaneous levels (i.e., TA100) and 3 times for those with low spontaneous levels (TA1537, TA98, TA1535, and WP2 uvrA). These increases should be seen in at least 2 or more successive concentrations or the response should be repeatable at a single concentration.

Rationale for test conditions:

Per OECD 471.

Evaluation criteria:

Criteria for a Positive Response:

The test substance was considered positive for mutagenicity if it induced an increase of revertants per plate with increasing concentration. The increases should be at least 2 times the vehicle control background frequency for strains with high spontaneous levels (i.e., TA100) and 3 times for those with low spontaneous levels (TA1537, TA98, TA1535, and WP2 uvrA). These increases should be seen in at least 2 or more successive concentrations or the response should be repeatable at a single concentration.

Criteria for a Negative Response:

The test substance was considered to be negative for inducing mutagenicity if it did not induce a response which fulfills the criteria for a positive response.

Statistics:

For each concentration level and for each condition, the mean revertant count and standard deviation (SD) were determined.

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:

cytotoxicity

Remarks:

Cytotoxicity at 250 ug/plate and greater without metabolic activation and 1000 ug/plate with metabolic activation.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

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:

cytotoxicity

Remarks:

Cytotoxicity at 100 ug/plate and greater without metabolic activation and 500 ug/plate and greater with metabolic activation

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

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:

cytotoxicity

Remarks:

Cytotoxicity at 100 ug/plate and greater without metabolic activation and at 500 ug/plate and greater with metabolic activation.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

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:

cytotoxicity

Remarks:

Cytotoxicity at 500 ug/plate and greater without metabolic activation and 1000 ug/plate with metabolic activation.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

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 nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Data on pH: 4.4
- Data on osmolality: No data
- Possibility of evaporation from medium: Not expected based on analytical conducted on dosing solutions.
- Water solubility: the average measured water solubility of the 2-octyl acrylate isomer is 4.98 mg/L (RSD=21%), the average water solubility of the 3-octyl acrylate isomer is 5.24 mg/L (RSD=19%), and the average water solubility of the 4-octyl acrylate isomer is 4.35 mg/L (RSD=16%) at 24.2°C
- Precipitation and time of the determination: No precipitation was observed.

RANGE-FINDING/SCREENING STUDIES (if applicable): See "Test concentrations with justification for top dose" field.

STUDY RESULTS
- Concurrent vehicle negative and positive control data : Vehicle and positive controls performed as expected and were within historical ranges for the laboratory.

For all test methods and criteria for data analysis and interpretation:
- Concentration-response relationship where possible : No increase in revertant colonies was observed.
- Statistical analysis: For each concentration level and for each condition, the mean revertant count and standard deviation (SD) were determined.

Ames test:
- Signs of toxicity : Cytotoxicity was observed at ≥ 100 µg/plate in strains TA1537 and TA100 without metabolic activation; at ≥ 250 µg/plate in strain TA1335 without metabolic activation; and at ≥ 500 µg/plate in strains TA98 without metabolic activation and TA1537 and TA100 with metabolic activation. Cytotoxicity was also observed at 1000 µg/plate in strains TA98 and TA1535 with metabolic activation. No cytotoxicity was observed with strain WP2 uvrA with or without metabolic activation.
- Individual plate counts : See attached table.
- Mean number of revertant colonies per plate and standard deviation : See attached table.

Applicant's summary and conclusion

Conclusions:

MTDID 44428 is negative in the bacterial reverse mutation assay (Ames assay) in the presence and absence of metabolic activation (S9).

Executive summary:

MTDID 44428 was evaluated for mutagenic activity in the in vitro bacterial reverse mutation assay. Four tester strains of Salmonella typhimurium(TA1537, TA98, TA100, and TA1535) and Escherichia coli strain (WP2uvrA) were used for mutagenicity testing. The study was conducted according to OECD 471 in compliance with OECD GLP. MTDID 44428 was prepared as a stock formulation in 200 proof ethanol at concentrations up to 50 mg/mL for each assay. Mutagenicity testing was performed in triplicate at each concentration with and without an Aroclor 1254-induced rat liver S9 metabolic activation system. In the range-finding assay, MTDID 44428 was tested in single plates at 1, 5, 10, 50, 100, 500, 1000, and 5000 µg/plate with strains TA100 and WP2uvrA using the plate incorporation method. Precipitates were not observed at any concentration in both strains with and without metabolic activation. Cytotoxicity (i.e., reduction in the background lawn and/or mean number of revertant colonies) was observed at ≥ 500 µg/plate in TA100 without metabolic activation and ≥ 1000 µg/plate in TA100 with metabolic activation. In the mutagenicity assay, MTDID 44428 was tested 5, 10, 25, 50, 100, 250, 500, and 1000 µg/plate in strains TA1537, TA98, TA1535, and TA100, and 100, 250, 500, 1000, 2500, and 5000 µg/plate in strain WP2 uvrA, using the plate incorporation method. Precipitates were not observed at any concentration, in any strain with or without metabolic activation. Cytotoxicity was observed at ≥ 100 µg/plate in strains TA1537 and TA100 without metabolic activation; at ≥ 250 µg/plate in strain TA1535 without metabolic activation; and at ≥ 500 µg/plate in strains TA98 without metabolic activation and TA1537 and TA100 with metabolic activation. Cytotoxicity was also observed at 1000 µg/plate in strains TA98 and TA1535 with metabolic activation. No cytotoxicity was observed with strain WP2 uvrA with or without metabolic activation. In the mutagenicity assay, criteria for a negative response were met for all tester strains with and without metabolic activation. The data from the vehicle and positive controls demonstrated the validity and sensitivity of this test system for detecting chemical mutagens with and without metabolic activation. These data support the conclusion that MTDID 44428 is negative for mutagenic activity in the S. typhimurium strains TA1537, TA98, TA100, and TA1535 and in the E. coli strain WP2 uvrA, with and without metabolic activation, under the conditions of this assay.