Tris(trimethylsilyl) phosphate

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:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted: July 21, 1997 (OECD, 1997) corrected on 26 June 2020

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Tris(trimethylsilyl) phosphate

EC Number:

234-028-1

EC Name:

Tris(trimethylsilyl) phosphate

Cas Number:

10497-05-9

Molecular formula:

C9H27O4PSi3

IUPAC Name:

tritrimethylsilyl phosphate

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: Provided by sponsor, Batch No.: N200611031

- Purity:99.28%



STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Refrigeration (+2 to +8ºC)

Method

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:

Type and composition of metabolic activation system:
- source of S9 ：
The S9 homogenate is prepared from male Wistar rats induced with a single intraperitoneal injection of Aroclor 1254 (0.5 mL to 0.7 mL/rat ready to use solution), 5 days prior to sacrifice.

- method of preparation of S9 mix ：
The S9 homogenate will be thawed immediately before use and mixed with the co-factor solution containing 4 mM NADP, 5 mM Glucose-6-phosphate, 8 mM MgCl2 and 33 mM KCl in PBS to achieve a final concentration of 10% S9 (v/v) fraction in the activation mixture.

- concentration or volume of S9 mix and S9 in the final culture medium
a final concentration of 10% S9 (v/v) fraction in the activation mixture.

Test concentrations with justification for top dose:

In the preliminary toxicity test, Salmonella typhimurium, TA 100 was exposed to test item at 50, 100, 200, 400, 800, 1600, 3200 and 5000 µg/plate along with DMSO control using direct plate incorporation method.
The results of this preliminary toxicity test are presented in Table 1.
The test item did not precipitate on the basal agar plates up to 5000 µg/plate.
The test item did not show toxicity at any of the tested doses either in the presence or in the absence of metabolic activation as the intensity of the bacterial background lawn as well as the mean number of revertant colonies were comparable to the vehicle control plates.
Based on these observations, it is decided to test the OECD 471-recommended highest test dose of 5000 µg/plate in the mutation assay.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: [DMSO]

- Justification for choice of solvent/vehicle:
Since DMSO is one of the organic solvents which is most compatible with the positive controls used, with good reproducibility and reliability

- Justification for percentage of solvent in the final culture medium:

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

2-nitrofluorene

sodium azide

other: 2-Aminoanthracene

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration：Three replicates
- Number of independent experiments ：1

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding (if applicable): 1-2 x 109 cells/mL.
- Test substance added in medium; in agar (plate incorporation)
TREATMENT AND HARVEST SCHEDULE:
- Preincubation period, if applicable: approximately 20 to 30 minutes at 37 ± 1 ºC
- Exposure duration/duration of treatment: incubated at 37 ± 1 °C for 48 to 72 hours



FOR GENE MUTATION:
- Expression time (cells in growth medium between treatment and selection): 48 to 72 hours.


- Number of cells seeded and method to enumerate numbers of viable and mutants cells: Viable counts for the different bacterial strains on nutrient agar plates will be counted manually.

Evaluation criteria:

The conditions necessary for determining a positive result are, there should be a dose related increase in the mean revertants per plate of at least one tester strain over a minimum of two increasing doses of the test item either in the presence or absence of the metabolic activation system.
The test will be judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than 2 times the mean vehicle control value for the strains TA98, TA100 and WP2uvrA (pKM101) or equal to or greater than 3 times the mean vehicle control value for the strains TA1535 and TA1537.
An equivocal response is a biologically relevant increase in a revertant count that partially meets the criteria for evaluation as positive. This could be a dose responsive increase that does not achieve the respective threshold cited above or a non-dose responsive increase that is equal to or greater than the respective threshold cited. A response will be evaluated as negative, if it is neither positive nor equivocal.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1535

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

Test results 2

Species / strain:

S. typhimurium TA 1537

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

Test results 3

Species / strain:

S. typhimurium TA 98

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

Test results 4

Species / strain:

S. typhimurium TA 100

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

Test results 5

Species / strain:

E. coli WP2 uvr A pKM 101

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

Remarks on result:

not determinable

Applicant's summary and conclusion

Conclusions:

It is concluded that the test item, TRIS (TRIMETHYLSILYL) PHOSPHATE is not mutagenic in this Bacterial Reverse Mutation Assay up to the highest OECD 471-recommended dose of 5000 µg/plate, under the conditions of testing employed.

Executive summary:

In a reverse gene mutation assay in bacteria (G20741), strains TA98, TA100, TA1535 and TA1537 of S. typhimurium and strain Escherichia coli: WP2uvrA (pKM101) were exposed to Tris(trimethylsilyl) phosphate(99.28%),  at concentrations of 50,158 , 500,  1581 and 5000 µg/plate in the presence and absence of mammalian metabolic activation using the pre-incubation method. 

The test item did not show toxicity to the tester strain at any of the tested doses as the intensity of the bacterial background lawn and the mean number of revertant colonies was comparable to the vehicle control plates. The test item did not precipitate on the basal agar plates at any of the tested doses up to 5000 µg/plate. The positive controls induced  the appropriate responses in the corresponding strains. There was no evidence  of induced mutant colonies over background.Based on these observations, is concluded that the test item, Tris(trimethylsilyl) phosphate is not mutagenic in this Bacterial Reverse Mutation Assay up to the highest OECD 471-recommended dose of 5000 µg/plate, under the conditions of testing employed.

 

This study is classified as acceptable .  This study satisfies  the requirement for Test Guideline  OPPTS 870.5100¹; OECD 471 for in vitro mutagenicity (bacterial reverse gene mutation) data.