Trimethyl citrate

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:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Trimethyl citrate

EC Number:

216-449-2

EC Name:

Trimethyl citrate

Cas Number:

1587-20-8

Molecular formula:

C9H14O7

IUPAC Name:

1,2,3-trimethyl 2-hydroxypropane-1,2,3-tricarboxylate

Specific details on test material used for the study:

6.1 Test Item
Designation in Test Facility: 17100206G
Date of Receipt: 02. Oct. 2017
Condition at Receipt Room temperature, in proper conditions
6.1.1 Specification
The following information concerning identity and composition of the test item was provid-ed by the sponsor.
Name Trimethyl citrate
Batch no. 20170901
Appearance white crystalline powder
Composition Trimethyl citrate
Purity 99.4%
Homogeneity homogeneous
Expiry date 01. Sep. 2019
Storage Room Temperature: (20 ± 5°C)

The following additional information is relevant to the conduct of the study, according to
OECD 471:
CAS No. 1587-20-8
EINECS-No. 216-449-2
Stability H2O: unknown; EtOH: unknown; Aceton: unknown; CH3CN: unknown; DMSO: unknown
Solubility H2O: unknown; EtOH: unknown; Aceton: unknown; CH3CN: unknown; DMSO: unknown

It was provided by the sponsor as well.

6.1.2 Storage
The test item was stored in the test facility in a closed vessel at room temperature (20±5°C).

Method

Target gene:

hisD6610
hisD3052
hisG46
hisG428
uvrB
rfa
pKM101
pAQ1

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 102

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 100

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 98

Species / strain 5

Species / strain / cell type:

S. typhimurium TA 97

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

In a non-GLP pre-test, the solubility of the test item was tested in a concentration of 50 g/L in demineralized water, dimethyl sulfoxide (DMSO) and acetone.
The solid test item is sufficiently soluble in DMSO.
Based on the non-GLP pre-test, DMSO was chosen as vehicle, because the test item was sufficiently soluble, and this solvent does not have any effects on the viability of the bacteria or the number of spontaneous revertants in the tested concentrations.
On the day of the start of the first and the second experiment, a stock solution containing 50 g/L of the test item in DMSO was prepared. The test item solution was not sterile filtrat-ed before use.
The stock solution was used to prepare the geometric series of the concentrations to be tested. The following nominal concentrations were prepared for the first experiment:
5000 µg/plate, 1500 µg/plate, 500 µg/plate, 150 µg/plate and 50 µg/plate.

The following nominal concentrations were prepared for the second experiment:
5000 µg/plate, 2500 µg/plate, 1250 µg/plate, 625 µg/plate, 313 µg/plate, 156 µg/plate and 78 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:

sodium azide

benzo(a)pyrene

other: 4-Nitro-1,2-phenylene Diamine; 2-Amino-Anthracene

Details on test system and experimental conditions:

All Salmonella typhimurium strains were obtained from TRINOVA BioChem GmbH (batch: TA97a: 4997D, TA98: 5011D, TA100: 4996D, TA102: 4982D, TA1535: 5012D) and were stored as lyophilizates in the refrigerator at 2-8 °C.
The lyophilizates were used to prepare permanent cultures which were filled into vials and stored at < - 75 °C.

Eight hours before the start of each experiment, an aliquot of a permanent culture per strain to be used was taken from the deep freezer to inoculate a culture vessel containing nutrient broth. After incubation overnight for eight hours at 37 ± 1 °C, the cultures were used in the experiment. During the test, the cultures were stored at room temperature as to prevent changes in the titre.

Evaluation criteria:

The colonies were counted visually and the numbers were recorded. A validated spread-sheet software (Microsoft Excel®) was used to calculate mean values and standard devia-tions of each treatment, solvent control and positive control.
The mean values and standard deviations of each threefold determination was calculated as well as the increase factor f(l) of revertant induction (mean revertants divided by mean spontaneous revertants) of the test item solutions and the positive controls. Additionally, the absolute number of revertants (Rev. Abs.) (mean revertants minus mean spontaneous revertants) was given.
A substance is considered to have mutagenic potential, if a reproducible increase of re-vertant colonies per plate exceeding an increase factor of 2 in at least one strain can be observed. A concentration-related increase over the range tested is also taken as a sign of mutagenic activity.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

Signs of toxicity were observed in the treatment with and without metabolic activation to-wards the bacteria strain TA98 in the highest concentration (5000 µg/plate)

Vehicle controls validity:

valid

Untreated 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:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 6

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

The test item Trimethyl citrate showed no increase in the number of revertants in all bacte-ria strains in both experiments.
All negative and all 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.

Applicant's summary and conclusion

Conclusions:

Based on the results of this study it is concluded that Trimethyl citrate is not muta-genic in the Salmonella typhimurium test strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in the present study.