Hydrolysis product of chloro(dimethyl)octadecylsilane and silica gel

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)

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)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

1

Reference substance name:

Hydrolysis product of chloro(dimethyl)octadecylsilane and silica gel

EC Number:

615-738-4

Cas Number:

72245-35-3

Molecular formula:

SiC20H43

IUPAC Name:

Hydrolysis product of chloro(dimethyl)octadecylsilane and silica gel

Method

Target gene:

bacterial

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:

S9 mix

Test concentrations with justification for top dose:

neat extract

Vehicle / solvent:

ddH2O and DMSO

Controls

Controls 1

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

other: 2-Aminoanthracene,

Remarks:

with S9 mix

Controls 2

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

2-nitrofluorene

sodium azide

other: Nitrofurantoine, 4-Nitro-1,2-phenilendiammine

Remarks:

without S9 mix

Details on test system and experimental conditions:

In this study the plate incorporation method was applied. The study was divided into 2 main phases:
In phase A, Salmonella typhimurium TA100 was exposed to the neat extract of the test substance prepared in DMSO and in ddH2O (2 different extracts). As cytotoxicity may vary in the presence of metabolic activation systems, the test was carried out in presence and in absence of S9 (-S9; +S9).
In phase B, the 4 bacteria strains were exposed to the neat extract of the test substance prepared in DMSO and ddH2O, in presence and in absence of a metabolic activation system (-S9; +S9).

Evaluation criteria:

Results of preliminary cytotoxicity test
The presence of the background is a confirmation of a correct bacterial growth (PASS), meaning absence of citotoxicity. On the contrary, when bacterial background is absent or dotted (FAIL), it means that cytotoxicity occurred.
Results of Ames Test
Acceptability criteria for positive controls: in order to be considered mutagenic, positive controls have to show an increase factor ≥ 2 for TA98, TA100 and WP2 strains, and ≥ 3 for TA1535 and TA1537.
Acceptance criteria for negative controls: negative controls should show a number of revertant colonies between 15 and 40 for TA98, TA1537 and TA1535 and between 80 and 180 for TA100 and WP2.

Results and discussion

Test results

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

under the test conditions applied, the test item is considered not to be mutagenic.