Diethoxy(dimethyl)silane

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1977 - 1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The study was conducted according to a Litton Bionetics Inc. method but full details are not available

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

no analytical purity stated; only single cultures tested, tester strains TA 102 or E. coli WP2 were not used in the study as required in the appropriate OECD test guideline

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Diethoxy(dimethyl)silane

EC Number:

201-127-6

EC Name:

Diethoxy(dimethyl)silane

Cas Number:

78-62-6

Molecular formula:

C6H16O2Si

IUPAC Name:

diethoxydimethylsilane

Details on test material:

- Name of test material (as cited in study report): Dimethyldiethoxysilane
- Physical state: colourless liquid

Method

Target gene:

his operon

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Species / strain 3

Species / strain / cell type:

E. coli, other: W3110/polA+

Species / strain 4

Species / strain / cell type:

E. coli, other: P3478/polA-

Species / strain 5

Species / strain / cell type:

yeast, other: Saccharomyces cerevisiae (D4)

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced rat liver S9-mix

Test concentrations with justification for top dose:

Main experiment:
- 0.001, 0.01, 0.1, 1, 5 µL/plate (with and without metabolic activation)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Solubility properties and relative non-toxicity to bacteria

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: -S9-mix: MNNG: 10 µg/plate (TA 1535, TA 100, D4), QM: 10 µg/plate (TA 1537), NF: 100 µg/plate (TA 1538, TA 98); +S9-mix: ANTH: 100 µg/plate (TA 1535, TA 100), AMQ: 100 µg/plate (TA 1537), AAF: 100 µg/plate (TA 1538, TA 98), DMNA: 100 µM/plate (D4)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Expression time (cells in growth medium): 48 h (Ames test), 24 h (DNA repair test)

NUMBER OF REPLICATIONS: single culture/test concentration

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:

A result is positive if the number of revertants is significantly increased compared with the solvent control to at least 2-fold of the solvent control for TA 100, TA 1535, TA 1537 and TA 1538, and 2-3 times the solvent control for TA 98 and D4.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium, other: TA 1535, TA1537, TA98, and TA100

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 applicable

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

≥1 µl/plate -S9-mix

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 3

Species / strain:

yeast, other: Saccharomyces cerevisiae (D4)

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 applicable

Positive controls validity:

valid

Test results 4

Species / strain:

E. coli, other: W3110/po1A+

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 applicable

Positive controls validity:

valid

Test results 5

Species / strain:

E. coli, other: P3478/po1A-

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 applicable

Positive controls validity:

valid

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Marked cytotoxicity was observed in tester strain TA 1538 in the absence of metabolic activation at concentration ≥1 µl/plate. No relevant cytotoxicity was observed for the other tester strains at any concentration either in the presence or in the absence of metabolic activation.

Any other information on results incl. tables

Table 1: Experiment 1 Plate incorporation Number of revertants per plate

	TA98			TA100			TA1535
Conc. µg/plate	— MA	+  MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)	—  MA	+ MA	Cytotoxic (yes/no)
0*	36	44	No	92	134	No	28	14	No
0.001	30	55	No	76	117	No	17	18	No
0.01	26	52	No	88	155	No	16	21	No
0.1	25	43	No	81	142	No	15	15	No
1	34	53	No	84	126	No	16	13	No
5	26	58	No	75	125	No	12	12	No
Positive control	>1000	>1000	No	610	811	No	>1000	299	No

*solvent control with DMSO

Table 2: Experiment 1 Plate incorporation Number of revertants per plate

	TA 1537			TA 1538			D4
Conc. µg/plate	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)	—  MA	+ MA	Cytotoxic (yes/no)
0*	14	15	No	28	31	No	44	154	No
0.001	30	14	No	15	31	No	48	222	No
0.01	19	26	No	26	31	No	42	64	No
0.1	22	19	No	23	29	No	46	202	No
1	14	18	No	14	30	No	43	234	No
5	10	13	No	15	35	No	50	228	No
Positive control	>1000	392	No	701	>1000	No	746	242	No

*solvent control with DMSO

Applicant's summary and conclusion

Conclusions:

No mutagenic effect was observed for the test substance tested up to cytotoxic concentration in any of the test strains in two independent experiments without and with metabolic activation. The test substance is non-mutagenic in test strains used.