3-chloropropyltrimethoxysilane

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium, other: TA98, TA100, TA1535, TA1537, TA1538, TA102

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

0.5 ml Aroclor 1254 induced rat liver S9

Test concentrations with justification for top dose:

100, 333, 1000, 3333 and 5000 µg/plate

Vehicle / solvent:

- Vehicle: DMSO at 50 µl

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with activation, all strains except TA 102

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other:  sterigmatocystin

Remarks:

TA 102 with activation

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

TA 98 and TA 1537 without activation

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

TA 100 and TA 1535 without activation

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

cumene hydroperoxide

Remarks:

TA 102 without activation

Controls 6

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

E coli without activation

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48-72 hours
- Expression time (cells in growth medium): 48-72 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 48-72 hours

NUMBER OF REPLICATIONS: triplicate plates

DETERMINATION OF CYTOTOXICITY
- Method: other: condition of background lawn

Evaluation criteria:

All cultures must demonstrate the characteristic mean number of spontaneous revertants in the vehicle control as shown below:  

TA98          10 - 50
TA100         80 - 240
TA1535         5 - 45
TA1537         3 - 21
TA1538         5 - 35
TA102        200- 380
WP2uvrA     10 - 60

For the test article to be evaluated positive, it must cause a dose-related increase in the mean revertants per plate of at least one tester strain with a minimum of two increasing concentrations of test article. Data sets for strains TA1535, TA1537 and TA1538 will be judged positive if the increase in mean revertants at the peak of the dose response is equal to greater than three times the mean vehicle control value. Data sets for strains TA98, TA100, and WP2uvrA will be 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 control value.

Statistics:

None

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

none

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium, other: TA100 and TA1535

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

bacteria, other: Salmonella typhimurium TA1537, TA1538, TA102; Escherichia coli/WP2uvrA

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

No precipitate or bacterial toxicity was observed in this assay. 
A positive response was observed with bacterial tester strain TA-98 in the absence of metabolic activation and tester strains TA-100 and TA-1535 with and without metabolic activation. The authors concluded that under these experimental conditions, the test material caused mutagenicity in three bacterial tester strains.
Cytotoxic concentration: 
*   With metabolic activation:  No toxicity observed at the  maximum dose of 5000 ug/plate
*   Without metabolic activation: No toxicity observed at the  maximum dose of 5000 ug/plate
Genotoxic effects (e.g. positive, negative, unconfirmed, dose-response, equivocal): 
*   With metabolic activation: Positive in TA-100 and TA-1535
*   Without metabolic activation: Positive in TA-98, TA-100 and TA-1535

Remarks on result:

other: all strains/cell types tested

Any other information on results incl. tables

Table 1: Dose range-finding study

	TA 100			E.coli WP2 uvrA
Conc. (µl/ml)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0	122	129	no	13	15	no
6.7	140	163	no	16	23	no
10	121	140	no	11	15	no
33	142	129	no	17	14	no
67	143	118	no	26	18	no
100	144	119	no	20	21	no
333	151	129	no	20	23	no
667	148	158	no	26	10	no
1000	209	196	no	25	18	no
3333	298	275	no	22	20	no
5000	308	446	no	23	27	no

*solvent control with DMSO

 

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

	TA 98			TA 100			TA 1535
Conc. (µl/ml)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0*	19	NT	no	115	169	no	9	12	no
100	12	NT	no	137	168	no	18	13	no
333	24	NT	no	148	166	no	21	16	no
1000	30	NT	no	136	206	no	61	41	no
3333	34	NT	no	232	271	no	138	165	no
5000	43	NT	no	246	356	no	190	248	no
Positive control	262	NT	no	494	1023	no	428	176	no

*solvent control with DMSO

NT: not tested

 

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

	TA 1537			TA 1538			TA 102			E.coli WP2 uvrA
Conc. (µl/ml)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0*	7	7	no	6	23	no	263	359	no	17	21	no
100	6	7	no	4	16	no	30	348	no	18	12	no
333	6	12	no	6	18	no	309	358	no	14	22	no
1000	9	9	no	6	20	no	295	414	no	20	22	no
3333	6	9	no	9	22	no	314	409	no	25	27	no
5000	9	8	no	11	18	no	329	404	no	23	25	no
Positive control	1052	129	no	321	944	no	1300	2312	no	132	570	no

*solvent control with DMSO

Applicant's summary and conclusion

Conclusions:

(3-Chloropropyl)trimethoxysilane has been tested for mutagenicity in a valid gene mutation study in bacterial strains S. typhimurium TA-98,TA-100,TA-1535,TA-1537,TA-1538, TA-102 and E. coli WP2 uvr A with and without metabolic activation, conducted according to a protocol similar to OECD Test Guideline 471 and in compliance with GLP. An dose-dependent increase in the number of revertants was observed in S. typhimurium strains TA100 and TA1535 with and without metabolic activation, and in strain TA98 in the absence of metabolic activation. It is concluded that (3-chloropropyl)trimethoxysilane is positive for mutagenicity in bacteria under the conditions of this test.