Triethoxy(3-isocyanatopropyl)silane

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Gene mutation (Bacterial reverse mutation assay / Ames test): negative with and without activation in Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 and E.coli WP2 uvrA (similar to OECD TG 471) (BioReliance, 1999).

In vitro chromosomal aberration test: negative with metabolic activation and positive without metabolic activation (according to OECD TG 473) (Eurofins, 2019).

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999-03-11 to 1999-08-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

guideline not mentioned.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Aroclor induced rat liver S9

Test concentrations with justification for top dose:

Pre-experiment with and without metabolic activation:
6.7, 10, 33, 67, 100, 333, 667, 1000, 3333, 5000 µg/plate
Main experiment:
with metabolic activation:
25, 75, 200, 600, 1800, 5000 µg/plate
without metabolic activation:
7.5, 25, 75, 200, 600, 1800 µg/plate

Vehicle / solvent:

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

- Justification for choice of solvent/vehicle: Solubility properties and relative non-toxicity to bacteria

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

All salmonella strains + WP2 uvrA (with activation)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

TA 98 (without activation)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

TA 100, TA 1535 (without activation)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

TA 1537 (without activation)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

WP2 uvrA

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar preincubation

DURATION

- Preincubation period: 60 minutes

- Expression time (cells in growth medium): 48 - 72 hours

NUMBER OF REPLICATIONS: 3 plates for each test concentration

DETERMINATION OF CYTOTOXICITY
- Method: Background lawn assessment, revertant colony counts

METABOLIC ACTIVATION: S9 was prepared from male Sprague Dawley rates induced with a single ip dose of Aroclor 1254, 500 mg/kg bw, 5 days before sacrifice. Each preparation of S9 was assayed for ability to metabolise 2-aminoanthracene and 7,12-dimethylbenz(a)anthracene to forms mutagenic to TA 100. S9 mix contained 10% S9, 5mM glucose-6-phosphate, 4 mM NADP, 8 mM MgCl2, 33 mM KCl. 0.5 ml was added to 100 microlitre vehicle or test article and (after pre-incubation) 2.0 ml top agar. The final concentration of S9 was therefore approximately 2%.

Evaluation criteria:

Cytotoxicity is defined as a reduction in the number of colonies by >50% compared with the solvent control and/or at least a moderate reduction in
the background lawn (background code 3,4 or 5).

The mean of each positive control must exhibit at least a three-fold increase in the number of revertants over the mean value of the respective vehicle control.

A minimum of three non-toxic dose levels are required to evaluate assay data.

A dose level is considered toxic if one or both of the following are met: (1) A >50 % reduction in the mean number of revertants per plate as
compared to the mean vehicle control. This reduction must be accompanied by an abrupt dose-dependant drop in the revertant count. (2) A reduction in the background lawn.

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

600 - 1800 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1800 - 5000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

600 - 1800 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1800 - 5000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

600 - 1800 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1800 - 5000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

600 - 1800 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

600 - 5000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1800 - 5000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

600 - 5000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

COMPARISON WITH HISTORICAL CONTROL DATA: Results were within range of historical control data

Table 2: Dose range-finding study Number of revertants per plate (2 plates per strain)

	TA 100			WP2 uvrA
Concentration (μg/Plate)	Plate 1 + MA	Plate 2 - MA	Cytotoxic (Yes/No)	Plate 1 + MA	Plate 2 - MA	Cytotoxic (Yes/No)
0	133	98	No	16	23	No
6.7	128	110	No	13	8	No
10	123	95	No	28	17	No
33	134	98	No	13	9	No
67	150	84	No	19	19	No
100	147	111	No	17	15	No
333	146	107	No	11	20	No
667	134	104	No	22	26	No
1000	148	123	No	32	16	No
3333	146	116	No	15	18	No
5000	168	113	No	24	16	No

*solvent control with DMSO

Table 3: Experiment 1 Mutagenicity Assay Number of revertants per plate (mean of 3 plates)

	TA98			TA100			TA1535
Conc. (µg/plate)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	16	27	No	134	161	No	11	12	No
100	21	30	No	131	156	No	11	11	No
333	11	24	No	134	163	No	10	14	No
1000	20	24	No	129	164	No	12	13	No
3333	20	32	No	141	167	No	9	11	No
5000	15	28	No	126	172	No	10	15	No
Positive control	367	873	No	720	1035	No	637	129	No

*solvent control with DMSO

Table 3: Experiment 1 Mutagenicity Assay Number of revertants per plate (mean of 3 plates)

	TA1537			WP2uvrA
Conc. (µg/plate)	— MA	+  MA	Cytotoxic (yes/no)	— MA	+  MA	Cytotoxic (yes/no)
0*	5	12	No	17	19	No
100	4	8	No	14	18	No
333	6	8	No	17	13	No
1000	4	9	No	10	16	No
3333	6	8	Yes	16	15	No
5000	6	6	Yes	17	14	No
Positive control	1070	119	No	292	108	No

*solvent control with DMSO

Table 4: Experiment 2 Mutagenicity Assay Number of revertants per plate (mean of 3 plates)

	TA98			TA100			TA1535
Conc. (µg/plate)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	26	44	No	106	129	No	10	12	No
33	26	39	No	121	131	No	11	11	No
100	24	46	No	136	153	No	9	16	No
333	26	35	No	117	142	No	11	14	No
1000	25	39	No	119	166	No	11	11	No
5000	19	38	No	138	167	No	11	10	No
Positive control	292	901	No	534	945	No	446	106	No

*solvent control with DMSO

Table 4: Experiment 2 Mutagenicity Assay Number of revertants per plate (mean of 3 plates)

	TA1537			WP2 uvrA
Conc. (µg/plate)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	6	5	No	21	14	No
33	5	6	No	16	14	No
100	5	7	No	21	15	No
333	4	6	No	18	15	No
1000	5	9	No	19	18	No
5000	3	7	Yes	22	15	No
Positive control	598	97	No	430	118	No

*solvent control with DMSO

Conclusions:

Triethoxy(3-isocyanatopropyl)silane has been tested according to a protocol that is similar to OECD 471 and in compliance with GLP in Salmonella typhimurium strains TA 98, TA 100, TA 1535 and TA 1537 and E. coli WP2 uvrA. No test substance induced increase in the number of revertants was observed in the presence or absence of metabolic activation when tested up to cytotoxic concentrations. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17th August 2017 to 07th December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosomal Aberration Test)

Version / remarks:

2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Details on mammalian cell type (if applicable):

CELLS USED
- Type and source of cells: Chinese hamster V79 cells from the cell bank of Eurofins Munich
- Suitability of cells: V79 cells in vitro are widely used to examine the ability of chemicals to induce cytogenetic changes and thus identify potential carcinogens or mutagens. These cells are chosen because of their relatively small number of chromosomes, their high proliferation rate and a high plating efficiency of untreated cells.

For cell lines:
- Absence of Mycoplasma contamination: yes
- Methods for maintenance in cell culture: The V79 cells (ATCC, CCL-93) were stored over liquid nitrogen (vapour phase) in the cell bank of Eurofins Munich, as large stock cultures allowing the repeated use of the same cell culture batch in experiments.
- Cell cycle length, doubling time or proliferation index : 12 - 14 h
- Modal number of chromosomes: (diploid number, 2n = 22
- Periodically checked for karyotype stability: yes
- Periodically ‘cleansed’ of spontaneous mutants: yes

MEDIA USED
- Type and composition of media, CO2 concentration, humidity level, temperature, if applicable: For the experiment thawed cultures were set up in 75 cm2 cell culture plastic flasks at 37 °C in a 5% carbon dioxide atmosphere (95% air). 5 x 105 cells per flask were seeded in 15 mL of MEM (minimum essential medium) supplemented with 10% FBS (fetal bovine serum) and subcultures were made 3-4 days after seeding.

Cytokinesis block (if used):

Colcemid (0.2 μg/mL culture medium) was added to the cultures around 17.5 h after the start of the treatment. About 2.5 h later preparation was started.

Metabolic activation:

with and without

Metabolic activation system:

Type and composition of metabolic activation system:
- source of S9 : phenobarbital (80 mg/kg bw) and β-naphthoflavone (100 mg/kg bw) induced male Wistar rat liver S9
- method of preparation of S9 mix: An appropriate quantity of the S9 supernatant was thawed and mixed with S9 cofactor solution to result in a final protein concentration of 0.75 mg/mL in the cultures. Cofactors were added to the S9 mix to reach the following concentrations: 8 mM MgCl2, 33 mM KCl, 5 mM Glucose-6-phosphate, 5 mM NADP in 100 mM sodium-phosphate-buffer pH 7.4. During the experiment the S9 mix was stored on ice.
- concentration or volume of S9 mix and S9 in the final culture medium: The final percentage of S9 mix in cell culture medium is 5% (v/v).
- quality controls of S9 (e.g., enzymatic activity, sterility, metabolic capability): Biological activity in the Salmonella typhimurium assay using 2-aminoanthracene; the mouse lymphoma assay using benzo[a]pyrene; the chromosome aberration assay using cyclophosphamide. Sterility Test.

Test concentrations with justification for top dose:

without metabolic activation: 5, 10 and 20 μg/mL
with metabolic activation: 30, 40 and 70 μg/mL
The concentrations were selected on the basis of the data and the toxicity and precipitation observed the pre-experiment and taking into account the recommendations of the guidelines.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: A solubility test was performed with different solvents and vehicles up to the maximum recommended concentration of 2 mg/mL. Based on the results of the solubility test and due to sensitivity of the test item to hydrolysis, anhydrous DMSO was used as solvent. Different test item stock solutions were prepared in DMSO and added to the cells into the cell culture medium directly without prior dilution. The solvent was compatible with the survival of the cells and with the S9 activity.
- Justification for percentage of solvent in the final culture medium: 1% DMSO; v/v final concentration

Untreated negative controls:

yes

Remarks:

treatment medium

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

ethylmethanesulphonate

Remarks:

without metabolic activation

Untreated negative controls:

yes

Remarks:

treatment medium

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

with metabolic activation

Details on test system and experimental conditions:

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

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding (if applicable): About 1 x 10⁴ cells/mL were seeded into cell culture flasks with complete culture medium.
- Test substance added in medium

TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: 4 hours with and without metabolic activation
- Harvest time after the end of treatment (sampling/recovery times): The metaphases were prepared 21 h after start of treatment with the test item.

FOR CHROMOSOME ABERRATION AND MICRONUCLEUS:
- Spindle inhibitor (cytogenetic assays): Colcemid (0.2 μg/mL culture medium) was added to the cultures around 17.5 h after the start of the treatment. About 2.5 h later preparation was started.
- Methods of slide preparation and staining technique used including the stain used (for cytogenetic assays): At preparation the cells were trypsinised and resuspended in about 9 mL complete culture medium. An aliquot of each culture was removed to determine the cell count by a cell counter (AL-Systems).Then cultures were transferred into tubes and incubated with hypotonic solution (0.4% KCl) for 15-20 min. After hypotonic treatment the cells were fixed at least two times with methanol/glacial acetic acid (3:1) and spread onto glass microscope slides. After the fixation steps the slides were dried and stained with Giemsa. The slides were coverslipped using 2-3 drops of Eukitt(R). Afterwards they were air dried.
- Number of cells spread and analysed per concentration (number of replicate cultures and total number of cells scored): 150 Metaphases per culture were scored for structural chromosomal aberrations, except for the concentration 20 μg/mL in the experiment without metabolic activation. At least 300 well spread metaphases (containing 22 ± 1 centromeres) per concentration and validity controls were scored for cytogenetic damage.
- Criteria for scoring chromosome aberrations (selection of analysable cells and aberration identification): If observed, structural chromosomal aberrations, including breaks, fragments, deletions, exchanges and chromosomal disintegration were recorded. Gaps were recorded as well but not included in the calculation of the aberration rates. The definition of a gap is as follows: an achromatic region (occurring in one or both chromatids) independent of its width. The remaining visible chromosome regions should not be dislocated either longitudinally or laterally.
- Determination of polyploidy: Yes
- Determination of endoreplication: No

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method, e.g.: relative increase in cell count (RICC)
- Any supplementary information relevant to cytotoxicity:

METHODS FOR MEASUREMENT OF GENOTOXICITY: Number of chromosome aberrations

Rationale for test conditions:

Based on pre-test.

Evaluation criteria:

Providing that all acceptability criteria are fulfilled, a test chemical is considered to be clearly positive if, in any of the experimental conditions examined:
a) at least one of the test concentrations exhibits a statistically significant increase compared to the concurrent negative control,
b) the increase is dose-dependent when evaluated with an appropriate trend test,
c) any of the results are outside the distribution of the historical negative control data
When all of these criteria are met, the test chemical is then considered able to induce chromosomal aberrations in cultured mammalian cells in this test system.

Statistics:

Statistical significance at the 5% level (p < 0.05) was evaluated by the Fischer´s exact test. The p value was used as a limit in judging for significance levels in comparison with the corresponding solvent control. Aberrant cells without gaps were only used for the calculation. Gaps are recorded separately and reported but generally not included in the total aberration frequency calculation according to the guideline.

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 40 μg/mL and higher

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

without

Genotoxicity:

positive

Remarks:

Statistically significantly increased number of aberrant cells at 10 μg/mL and higher

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 10 μg/mL and higher

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Data on pH: The pH value was within the physiological range (7.0 ± 0.4) during the preparation of the test material.
- Data on osmolality: 456 mOsmol/kg was measured at the test item concentration of 100 μg/mL during the preparation of the test material.
- Possibility of evaporation from medium:
- Water solubility:
- Precipitation and time of the determination: No precipitation of the test item was noted at all concentrations evaluated in the main experiment without and with metabolic activation.
- Definition of acceptable cells for analysis:
- Other confounding effects:

RANGE-FINDING/SCREENING STUDIES (if applicable): A pre-experiment was conducted under identical conditions as described for the main experiment. The following concentrations were tested without and with S9 mix: 2, 5, 10, 20, 50, 100, 200, 500, 1000 and 2000 μg/mL. Cytotoxicity was characterised by the relative increase in cell count (RICC) in comparison to the controls.Precipitation occurred down to a concentration of 50 μg/mL (pre-experiment).

STUDY RESULTS
- Concurrent vehicle negative and positive control data : EMS (600 μg/mL) and CPA (1.11 μg/mL) were used as positive controls and induced distinct and biologically relevant increases in cells with structural chromosomal aberrations, thus proving the ability of the test system to indicate potential clastogenic effects. The negative and solvent controls did not induce any chromosomal aberrations.

For all test methods and criteria for data analysis and interpretation:
- Concentration-response relationship where possible : yes
- Statistical analysis: yes

Chromosome aberration test (CA) in mammalian cells:
- Results from cytotoxicity measurements:
o For cell lines: In the main experiment without metabolic activation, cytotoxic effects of the test item were noted at concentrations of 10 μg/mL and higher. With metabolic activation, cytotoxic effects of the test item were observed at concentrations of 40 μg/mL and higher.
- Genotoxicity results (for both cell lines and lymphocytes)
o Definition for chromosome aberrations, including gaps : structural chromosomal aberrations include breaks, fragments, deletions, exchanges and chromosomal disintegration. The definition of a gap is: an achromatic region (occurring in one or both chromatids) independent of its width. The remaining visible chromosome regions should not be dislocated either longitudinally or laterally.
o 150 Metaphases per culture were scored for structural chromosomal aberrations, except for the concentration 20 μg/mL in the experiment without metabolic activation. In the main experiment, an increase of aberrant cells was noted at concentrations of 10 μg/mL and higher without metabolic activation and at a concentration of 70 μg/mL with metabolic activation.
o Changes in ploidy (polyploidy cells and cells with endoreduplicated chromosomes) if seen : An increase in polyploidy was noted only in one of the duplicate cultures of the main experiment without metabolic activation in the concentrations 10 μg/mL and 20 μg/mL. No biologically relevant increase in the frequencies of polyploid cells was found after treatment with the test item in the experiment with metabolic activation.

HISTORICAL CONTROL DATA (with ranges, means and standard deviation, and 95% control limits for the distribution as well as the number of data)
- Positive historical control data: See table 1
- Negative (solvent/vehicle) historical control data: See table 1

Table 1: Summary: Main Experiment , without and with metabolic activation

Dose group	Concentration [µg/mL]	RICC [%]	Mean aberrant cells	Mean aberrant cells	Historical Laboratory Negative Control Range	Precipitation	Statistical significance
			Incl. gaps	Excl. gaps
	Without S9 mix, 4 h treatment, 21 h preparation interval				-0.28% - 3.70% aberrant cells excl. gaps
C	0	103	2.7	2.0		-	-
S	0	100	3.0	2.0		-	-
2	5	104	0.3	0.3		-	-
3	10	66	9.3	6.0		-	+
4	20	50	11.7	10.3		-	+
EMS	600	93	9.3	7.7		-	+
	With S9 mix, 4 h treatment, 21 h preparation interval				-0.23% - 3.95% aberrant cells excl. gaps
C	0	101	2.0	1.7		-	-
S	0	100	2.7	1.7		-	-
4	30	85	2.7	1.3		-	-
5	40	73	2.7	2.3		-	-
7	70	41	4.7	4.3		-	-
CPA	1.11	80	10.3	9.7		-	+

C: Negative Control (Culture Medium)

S: Solvent Control (DMSO)

EMS: Ethylmethanesulfonate

CPA: Cyclophosphamide

RICC: Relative Increase in Cell Count, calculated by the increase in cell number of the test groups compared to the solvent control groups. The cell count was determined by a cell counter per culture for each test group.

a: - without precipitation, + with precipitation

b: statistical significant increase compared to solvent controls (Fisher’s exact test, p< 0.05), +: significant; -not significant

Conclusions:

Triethoxy(3-isocyanatopropyl)silane has been tested for ability to cause chromosome aberrations in Chinese hamster V79 cells according to OECD Test Guideline 473 and in compliance with GLP (Eurofins, 2019). No increase in the number of cells with aberrations was observed with metabolic activation in Chinese hamster V79 cells. A statistically significant increase in the number of aberrant cells was observed when tested without metabolic activation. Appropriate solvent, negative (treatment medium) and positive controls were included and gave expected results. It is concluded that the test substance is positive for the induction of chromosome aberrations under the conditions of this study.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (positive)

Genetic toxicity in vivo

Description of key information

There are no in vivo genetic toxicity tests for triethoxy(3-isocyanatopropyl)silane. As the result of the in vitro cytogenicity study according to the OECD Test Guideline 473 is a clear positive without metabolic activation, with an increase in the number of aberrations relative to control which is statistically significant and dose-dependent, an in vivo comet assay will be conducted after approval by ECHA.

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Triethoxy(3-isocyanatopropyl)silane has been tested according to a protocol that is similar to OECD 471 and under GLP in Salmonella typhimurium strains TA 98, TA 100, TA 1535 and TA 1537 and E. coli WP2 uvrA (BioReliance, 1999). No test substance induced increase in the number of revertants was observed in the presence or absence of metabolic activation when tested up to cytotoxic concentrations. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.

Triethoxy(3-isocyanatopropyl)silane has been tested for ability to cause chromosome aberrations in Chinese hamster V79 cells according to OECD Test Guideline 473 and in compliance with GLP (Eurofins, 2019). No increase in the number of cells with aberrations was observed with metabolic activation in Chinese hamster V79 cells. Statistically significant increase in the number of aberrant cells was observed when tested without metabolic activation. Appropriate solvent, negative (treatment medium) and positive controls were included and gave expected results. It is concluded that the test substance is positive for the induction of chromosome aberrations under the conditions of this study.

Data for the hydrolysis product, 3-aminopropyl(triethoxy)silane (CAS 919-30-2), have been added to the dataset as supporting information for completeness, but are not used in the assessment as the parent substance has reliable data and a testing proposal for a comet assay to investigate the genetic toxicity potential further.

Justification for classification or non-classification

Insufficient information is available to conclude on the classification for mutagenicity of triethoxy(3-isocyanatopropyl)silane according to Regulation (EC) No.1272/2008.