Silanediol, 1-methyl-1-(1-methylethoxy)-, 1,1-diacetate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 - 21 May 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

: lack of data on test substance, no purity given

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

442-070-9

EC Name:

-

Cas Number:

329039-38-5

Molecular formula:

Hill formula: C8 H16 O5 Si CAS formula: C8 H16 O5 Si

IUPAC Name:

(acetyloxy)(methyl)(propan-2-yloxy)silyl acetate

Details on test material:

- Name of test material (as cited in study report): Experimental Acetoxysilane Derivative
- Physical state: clear, colorless liquid
- Analytical purity: 85.8 %
- Impurities (identity and concentrations): 12.9 % Acetoxydiisopropoxymethtylsilane, 1.3 % hydrolisis product (siloxane)
- Purity test date: 04.10.2001
- Lot/batch No.: AA001
- Storage condition of test material: moved from room temperature on 30. April 2001 to 2-8 °C in an airlight container under nitrogen, protected from light and moisture

Method

Target gene:

Salmonella typhimurium: his operon
Escherichia coli: trp operon

Species / strain

Species / strain 1

Species / strain / cell type:

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

Additional strain / cell type characteristics:

other: rfa-; uvrB- (R+ for TA 98 and TA 100)

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

other: uvrA-

Metabolic activation:

with and without

Metabolic activation system:

cofactor supplemented post-mitochondrial fraction (S9 mix) prepared from the livers of rats treated with Aroclor 1254.

Test concentrations with justification for top dose:

First experiment: 2.5, 7.5, 25, 75, 200, 600, 1800 and 5000 µg/plate with and without metabolic activation
Second experiment: 75, 200, 600, 1800 and 5000 µg/plate with and without metabolic activation

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: A solubility test was conducted to select the vehicle. The test item was tested to determine the vehicle that permitted preparation of the highest soluble and workable stock concentration, up to 500 mg/mL.

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 1 µg/plate sodium azide (TA100 and 1535,-S9), 1 µg/plate 2-nitrofluorene (TA98,-S9), 75 µg/plate 9-aminoacridine (TA1537,-S9), 1 µg/plate methyl methane sulfonate (WP2 uvrA,-S9), 1 µg/plate 2-AA (TA98, 100, 1535, 1537, +S9) and 10 µg/plate 2-AA (WP2 uvrA)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 to 72 hours


NUMBER OF REPLICATIONS: duplicates in Experiment 1 (and 1.1) and triplicates in Experiment 2


DETERMINATION OF CYTOTOXICITY
- Method: bacterial background lawn

Evaluation criteria:

For each replicate plating, the mean and standard deviation of the number of revertants per plate were claculated and reported.
For the test item to be evaluated positive, it must cause a dose-related increase in the mean revertants per plate of at least one tester strain over a minimum of two increasing concentrations of the test item. Data sets for tester strains TA 1535 and TA 1537 were judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than three times the mean vehicle control value. Data sets for tester strains TA 98, TA 100 and WP2 uvrA were judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than two times the mean vehicle value.

Statistics:

Mean and standard deviation were calculated.

Results and discussion

Test results

Test results 1

Species / strain:

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

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

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

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: In the initial toxicity-mutation assay, the maximum dose tested was 5000 µg/plate. This dose was achieved using a concentration of 100 mg/mL and a 50 µL plating aliquot. Neither precipitate nor appreciable toxicity was observed in doses tested up to 5000 µg/plate.

COMPARISON WITH HISTORICAL CONTROL DATA: Yes

ADDITIONAL INFORMATION:
Due to the loss of plates to contamination in Experiment 1, tester strain TA 1535 without metabolic activation was retested (Experiment 1.1).

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Summary Ames Test Results – Experiment 1

With or without S9-Mix	Test substance concentration (μg/plate)	Mean number of revertant colonies per plate (average of triplicate)
		Base-pair substitution type		Frameshift type		Base-pair substitution and other
		TA 1535	TA 100	TA 1537	TA 98	WP2 uvrA
-	Vehicle control	16±7	115±35	4±1	12±1	10±0
-	2.5	12±9	139±19	7±5	8±0	13±1
-	7.5	10±--	139±6	5±1	12±0	12±2
-	25	11±3	114±43	7±4	10±1	10±0
-	75	--	97±21	8±4	9±4	10±2
-	200	5±--	115±11	8±4	12±6	9±3
-	600	5±1	128±8	5±3	11±1	7±3
-	1800	5±1	107±15	4±3	8±4	8±0
-	5000	10±1	70±6	3±2	15±9	8±1
Positive controls - S9	Name	NaN3	NaN3	9-AA	2-NF	MMS
	Concentrations (μg/plate)	1.0	1.0	75	1.0	10.
	Number of colonies/plate	344±18	481±66	250±9	113±19	65±10
		TA 1535	TA 100	TA 1537	TA 98	WP2 uvrA
+	Vehicle control	9±2	140±20	5±0	13±4	11±1
+	2.5	13±5	130±37	7±2	10±3	11±4
+	7.5	7±3	133±18	5±1	12±6	10±1
+	25	11±1	135±16	6±1	16±3	9±3
+	75	11±5	122±5	6±3	15±4	10±1
+	200	9±1	113±13	6±1	16±3	9±1
+	600	14±6	145±12	7±1	15±4	10±1
+	1800	13±4	118±7	5±2	12±7	11±2
+	5000	11±6	126±1	5±1	12±1	9±0
Positive controls + S9	Name	2-AA	2-AA	2-AA	2-AA	2-AA
	Concentrations (μg/plate)	1.0	1.0	1.0	1.0	10
	Number of colonies/plate	134±10	1099±644	91±9	578±255	110±8

Table 2: Summary Ames Test Results - Experiment 1.1

With or without S9-Mix	Test substance concentration (μg/plate)	Mean number of revertant colonies per plate (average of triplicate)
		Base-pair substitution type		Frameshift type		Base-pair substitution and other
		TA 1535
-	Vehicle control	10±6
-	2.5	11±1
-	7.5	13±1
-	25	13±4
-	75	16±7
-	200	12±4
-	600	17±1
-	1800	16±2
-	5000	18±4
Positive controls - S9	Name	NaN3
	Concentrations (μg/plate)	1.0
	Number of colonies/plate	300±9

Table 3: Summary Ames Test Results - Experiment 2

With or without S9-Mix	Test substance concentration (μg/plate)	Mean number of revertant colonies per plate (average of triplicate)
		Base-pair substitution type		Frameshift type		Base-pair substitution and other
		TA 1535	TA 100	TA 1537	TA 98	WP2 uvrA
-	Vehicle control	12±3	197±13	7±2	12±3	13±3
-	75	16±4	171±13	10±2	12±1	9±1
-	200	14±7	220±11	11±5	15±3	15±3
-	600	18±3	145±24	8±1	15±4	10±2
-	1800	14±3	142±6	8±4	15±4	9±4
-	5000	15±4	209±42	10±3	14±2	11±2
Positive controls - S9	Name	NaN3	NaN3	9-AA	2-NF	MMS
	Concentrations (μg/plate)	1.0	1.0	75	1.0	10.
	Number of colonies/plate	365±4	592±3	935±19	185±36	81±12
		TA 1535	TA 100	TA 1537	TA 98	WP2 uvrA
+	Vehicle control	8±2	201±11	9±5	15±3	11±3
+	75	10±2	197±10	7±0	16±3	11±3
+	200	13±2	260±9	11±1	16±3	12±1
+	600	12±2	228±22	6±2	12±2	9±2
+	1800	12±4	181±22	8±2	14±4	14±2
+	5000	10±3	185±20	11±1	13±6	11±3
Positive controls + S9	Name	2-AA	2-AA	2-AA	2-AA	2-AA
	Concentrations (μg/plate)	1.0	1.0	1.0	1.0	10
	Number of colonies/plate	246±31	1745±208	370±51	1465±127	80±11

NaN3 = sodium azide

2-AA = 2-aminoanthracene

9-AA = 9-aminoacridine

2-NF = 2-nitrofluorene

MMS = methyl methane sulfonate

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Executive summary:

Methyldiacetoxyisopropoxy silane was tested in an Ames test using Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100 and the Escherichia coli strain WP2 uvrA . The substance was tested up to 5000 µg/plate with and without metabolic activation. No toxic effects occurred in all test groups, with and without S9 mix. Under the experimental conditions the test item did not induce mutations by base pair changes or frameshifts in the genome of the strains used.