(3-chloropropyl)diethoxymethylsilane

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:

1995-05-03 to 1995-06-12

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate OECD test guideline, with acceptable restrictions. The restrictions were that the range of strains does not comply with the current guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

only 4 strains used

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Umwelt, Raumordnung und Landwirtschaft des Landes Nordrhein-Westfalen

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(3-chloropropyl)diethoxymethylsilane

EC Number:

236-828-6

EC Name:

(3-chloropropyl)diethoxymethylsilane

Cas Number:

13501-76-3

Molecular formula:

C8H19ClO2Si

IUPAC Name:

(3-chloropropyl)(diethoxymethyl)silane; (3-chloropropyl)diethoxymethylsilane; (4-chloro-1,1-diethoxybutyl)silane

Method

Target gene:

His operon

Species / strain

Species / strain / cell type:

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

Additional strain / cell type characteristics:

other: rfa, uvrB (TA 98 & TA 100: pKM 101)

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:

50, 160, 500, 1000 and 5000 µg/plate

Vehicle / solvent:

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

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

without metabolic activation: TA 98: 2.5 µg/plate in DMSO

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without metabolic activation: TA 100 & TA 1535: 2.5 µg/plate in aqua bidest

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

without metabolic activation: TA 1537: 25 µg/plate in DMSO

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with metabolic activation: All strains: 2.5 µg/plate in DMSO

Details on test system and experimental conditions:

METHOD OF APPLICATION:in agar (plate incorporation)

DURATION

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

NUMBER OF REPLICATIONS: 3 plates for each test concentration

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

Metabolic activation: Male Wistar rats recieved single i.p. injection of Aroclor 1254 ( 500 mg/kg body weight) in olive oil 5 days prior to the preparation of the S9 fraction. One part of S9 fraction was mixed with 9 parts of a cofactor solution resulting in the following mixture:
-10 % S9 fraction
-33 mM KCl
-8 mM MgCl2
-5 mM glucose-6-phosphate
-4 mM NADP, 100 mM Na2HPO4/NaH2PO4, pH 7.4.
0.5 ml of S9 mix were added to a total volume of 2.7 ml, giving a final concentration of approximately 1%

Evaluation criteria:

Solvent control data must be within range of historical data.

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 four non-toxic dose levels are required to evaluate assay data.

For a test substance to be considered positive, it must cause at least a doubling in the mean revertants per plate of at least one tester strain.
The increase must be accompanied by a dose response towards increasing concentrations of the test article.

Cytotoxicity is defined by a reduction in the number of revertant colonies and / or a clearing of the background lawn.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium, other: 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:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

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

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 2: Experiment 1 Preincubation 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)
Negative control**	29	41	No	146	135	No	11	14	No
0*	27	54	No	135	114	No	10	11	No
50	26	42	No	125	127	No	9	17	No
160	26	44	No	122	140	No	15	23	No
500	26	40	No	133	155	No	23	43	No
1600	25	41	No	160	154	No	64	93	No
5000	28	27	No	179	178	No	112	141	No
Positive control	129	553	No	412	1952	No	337	184	No

*solvent control with DMSO

**negative control with water

Table 2: Experiment 1 Preincubation Number of revertants per plate (mean of 3 plates)

	TA1537
Conc. (µg/plate)	— MA	+ MA	Cytotoxic (yes/no)
Negative control**	23	14	No
0*	18	12	No
50	21	14	No
160	14	13	No
500	14	12	No
1600	15	12	No
5000	13	13	No
Positive control	54	250	No

*solvent control with DMSO

**negative control with water

Table 3: Experiment 2 Plate incorporation 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)
Negative control**	21	43	No	129	138	No	8	12	No
0*	22	47	No	123	129	No	12	10	No
50	21	41	No	114	127	No	11	9	No
160	29	41	No	126	139	No	16	21	No
500	24	47	No	143	135	No	27	38	No
1600	28	42	No	167	149	No	64	83	No
5000	32	31	No	193	184	No	108	131	No
Positive control	112	1984	No	428	1711	No	275	198	No

*solvent control with DMSO

**negative control with water

Table 3: Experiment 2 Plate incorporation Number of revertants per plate (mean of 3 plates)

	TA1537
Conc. (µg/plate)	— MA	+ MA	Cytotoxic (yes/no)
Negative control**	14	20	No
0*	11	16	No
50	12	21	No
160	12	18	No
500	8	19	No
1600	9	15	No
5000	9	16	No
Positive control	80	120	No

*solvent control with DMSO

**negative control with water

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive with and without metabolic activation

In a bacterial reverse mutation assay according to OECD 471 and to GLP, (3-chloropropyl)diethoxymethylsilane induced a mutagenic effect in Salmonella typhimurium strains: TA 1535 with and without metabolic activation. Appropriate solvent and positive controls were used and gave expected results. The test substance is considered to be a direct-acting mutagen, inducing base pair mutations.