3-[3,3,3-trimethyl-1,1-bis[(trimethylsilyl)oxy]disiloxanyl]propyl methacrylate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The restrictions were that the number of cells evaluated does not comply with the current guideline. It was conducted in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

yes

Remarks:

The number of cells analysed does not comply with the current guideline

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

3-[3,3,3-trimethyl-1,1-bis[(trimethylsilyl)oxy]disiloxanyl]propyl methacrylate

EC Number:

241-165-0

EC Name:

3-[3,3,3-trimethyl-1,1-bis[(trimethylsilyl)oxy]disiloxanyl]propyl methacrylate

Cas Number:

17096-07-0

Molecular formula:

C16H38O5Si4

IUPAC Name:

3-{2,2,6,6-tetramethyl-4-[(trimethylsilyl)oxy]-3,5-dioxa-2,4,6-trisilaheptan-4-yl}propyl 2-methylprop-2-enoate

Test material form:

other: liquid

Method

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Details on mammalian cell type (if applicable):

- Type and identity of media: Ham's F12 medium
- Properly maintained: yes

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced S9 mix in rat liver

Test concentrations with justification for top dose:

5000, 2500, 1250, 625, 312.5, 156.3, 78.1, 39.1, 19.5, and 9.8 µg/ml

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: none given in the study report

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

without metabolic activation

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Dimethylnitrosamine

Remarks:

with metabolic activation

Details on test system and experimental conditions:

ACTIVATION: 1ml of S9 mix consisted of the following co-factors: S9 0.4 ml, MgCl2 33 µmol, KCL 8 µmol, Glucose-6-phosphate 5 µmol, NADH 4 µmol, NADPH 4 µmol, buffer pH 7.4 100 µmol. The final concentration of S9 was 4%.
METHOD OF APPLICATION: suspensions of test substance in medium

DURATION

- Exposure duration:
without metabolic activation: 12 or 24 hours
with metabolic activation: 3 hours
- Expression time (cells in growth medium):
with metabolic activation: 9 or 21 hours (3-hour treatment)
- Fixation time (start of exposure up to fixation or harvest of cells): 24 hours

SPINDLE INHIBITOR (cytogenetic assays): Colcemid solution (0.1 µh/ml) added 2 hours before the end of the incubation period
STAIN (for cytogenetic assays): 2% solution of Giemsa

NUMBER OF REPLICATIONS: duplicate cultures

NUMBER OF CELLS EVALUATED: 100 cells per culture

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index

OTHER EXAMINATIONS:
- Determination of polyploidy: yes

Evaluation criteria:

The main criterion to designate a positive result is a statistically significant, dose-related increase in the number of structural chromosome aberrations.

Statistics:

t-test

Results and discussion

Test results

Key result

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY: No test substance induced polyploidy was observed.

Any other information on results incl. tables

Table 1. Results on chromosome aberration test, without and with metabolic activation

Treatment	Treatment time	Treatment concentration µg/ml	Number of cells observed	Excluding gaps	Including gaps
				Number of cells with aberrations
Without metabolic activation
DMSO	12 hours	-	100	4	8
			100	2	6
			200	6 (3.0 %)	14 (7.0 %)
	24 hours	-	100	2	3
			100	6	7
			200	8 (4.0 %)	10 (5.0 %)
Test substance SK 5001P	12 hours	625.0	100	3	9
			100	11	15
			200	14 (7.0 %)	24 (12.0 %)
		1250.0	100	1	4
			100	1	3
			200	2 (1.0 %)	7 (3.5 %)
		2500.0	100	2	4
			100	1	4
			200	3 (1.5 %)	8 (4.0 %)
		5000.0	100	2	4
			100	1	4
			200	3 (1.5 %)	8 (4.0 %)
	24 hours	625.0	100	0	3
			100	0	3
			200	0 (0.0 %)	6 (3.0 %)
		1250.0	100	3	5
			100	3	7
			200	6 (3.0 %)	12 (6.0 %)
		2500.0	100	1	3
			100	4	8
			200	5 (2.5 %)	11 (5.5 %)
		5000.0	100	3	3
			100	2	11
			200	5 (2.5 %)	14 (7.0 %)
Positive control (MMC)	12 hours	0.05	100	40	51
			100	45	50
			200	85 (42.5 %)	101 (50.5 %)
	24 hours	0.05	100	81	86
			100	86	86
			200	167 (83.5 %)	172 (86.0 %)
With metabolic activation
DMSO	3 hour treatment, 9 hours recovery time	-	100	2	7
			100	3	7
			200	5 (2.5 %)	14 (7.0 %)
Treatment Substance SK 5001P		625.0	100	4	8
			100	3	8
			200	7 (3.5 %)	16 (8.0 %)
		1250.0	100	4	9
			100	0	2
			200	4 (2.0 %)	11 (5.5 %)
		2500.0	100	1	5
			100	5	9
			200	6 (3.0 %)	14 (7.0 %)
		5000.0	100	0	6
			100	4	11
			200	4 (2.0 %)	17 (8.5 %)
Positive control (DMN)		2000.0	100	26	30
			100	24	28
			200	50 (25.0 %)	58 (24.0 %)
DMSO	3 hours treatment, 21 hours recovery time	-	100	2	4
			100	6	15
			200	8 (4.0 %)	19 (9.5 %)
Treatment Substance SK 5001P		625.0	100	2	5
			100	2	7
			200	4 (2.0 %)	12 (6.0 %)
		1250.0	100	2	5
			100	0	3
			200	2 (1.0 %)	8 (4.0 %)
		2500.0	100	0	6
			100	1	7
			200	1 (0.5 %)	13 (6.5 %)
		5000.0	100	2	4
			100	6	9
			200	8 (4.0 %)	13 (6.5 %)
Positive control (DMN)		2000.0	100	31	36
			100	36	39
			200	67 (33.5 %)	75 (37.5 %)

Table 2. Mitotic index in Chinese hamster ovary cells treated with SK 5001P

Treatment	Concentration µg/ ml	Mitotic index (%)
		12 h	24 h
Without metabolic activation	Control (DMSO)	2.5	2.1
	625.0	0.7	2.0
	1250.0	0.6	0.9
	2500.0	0.6	1.4
	5000.0	1.3	1.0
With metabolic activation	Control (DMSO)	13.6	6.2
	625.0	11.4	3.3
	1250.0	14.2	6.3
	2500.0	11.4	4.7
	5000.0	13.7	5.4

MMC - mitomycin C

DMN - Dimethylnitrosamine

Applicant's summary and conclusion

Conclusions:

3-[3,3,3-Trimethyl-1,1-bis[(trimethylsilyl)oxy]disiloxanyl]propyl methacrylate has been tested in a valid study according to a protocol similar to OECD 473 and under GLP, up to limit concentrations. No increase in the number of cells with aberrations was observed either with or without metabolic activation in Chinese hamster Ovary cells. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for the induction of chromosome aberrations under the conditions of this study.