Dichloro(3-chloropropyl)methylsilane

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Dichloro(3-chloropropyl)methylsilane

EC Number:

232-136-3

EC Name:

Dichloro(3-chloropropyl)methylsilane

Cas Number:

7787-93-1

Molecular formula:

C4H9Cl3Si

IUPAC Name:

dichloro(3-chloropropyl)methylsilane

Method

Target gene:

HPRT locus

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Metabolic activation system:

Aroclor induced rat liver S9

Test concentrations with justification for top dose:

Test 1 -S9 - 120, 300, 600, 900, 1200 µg/ml +S9 - 200, 500, 1000, 1500, 2000 µg/ml Test 2 -S9 60, 120, 300, 600, 800 µg/ml, +S9 100, 200, 500, 1000, 1500 µg/ml

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Acetone
- Justification for choice of solvent/vehicle: It is assumed by the reviewer that the choice of solvent was based on solubility properties and relative non-toxicity to CHO cells.

Controls

Controls 1

Untreated negative controls:

yes

Remarks:

HO medium + 1 % acetone

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-(20)-Methylcholanthrene (MCA) 10 µg/ml

Remarks:

with activation

Controls 2

Untreated negative controls:

yes

Remarks:

HO medium + 1 % acetone

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

ethylmethanesulphonate

Remarks:

without activation 300 µg/ml

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 4 hours
- Expression time (cells in growth medium): 6-7 days
- Selection time (if incubation with a selection agent): 6-7 / 9 days
- Fixation time (start of exposure up to fixation or harvest of cells): 6-7 days

SELECTION AGENT (mutation assays): H10 medium

NUMBER OF REPLICATIONS: 3 for each test concentration

NUMBER OF CELLS EVALUATED: 1,000,000 cells/flask

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency; relative total growth

Evaluation criteria:

The test substance is mutagenic if it causes a statistically significant, dose related increase in mutant frequency at concentrations of the test substance resulting in greater than 20 % cell survival. The mean mutant frequency in treated cultures should reach a value above the maximum spontaneous mutant frequency.

Statistics:

Statistical significance is determined by t-test

absolute cloning efficiency (in %) = mean # of colonies per dish x 100 / number of plated cells per dish

relative cloning efficiency (in %) = absolute C.E. of treated cells x 100 / absolute C.E. of solvent control

mutation frequency = counted colonies (mean of 5 flasks) / absolute cloning efficiency (in %)

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 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

Any other information on results incl. tables

Table 2:Results of Mammalian Mutagenicity assay (Test 1) with CHO cells

Concentrationµg/ml	Mutant* Frequency	Mutant* Frequency	% Relative cloning eff.	% Relative cloning eff.	Cytotoxicity (yes/no)
-	— MA	+ MA	— MA	+ MA	-
0	1	3	94 / 103	98 / 107	No
0(1 % Acetone)	4	6	100	100	No
60	-	-	-	-	No
100	-	-	-	-	No
120	5	-	88 / 108	-	No
200	-	0	-	97 / 107	No
300	-	-	0	-	No
500	-	11 **	-	88 / 101	No
600	0	-	87 / 107	-	No
800	-	-	-	-	No
900	2	-	4 / 104	-	No
1000	-	7	-	73 / 101	No
1200	-	-	0	-	No
1500	-	0	-	32 / 94	No
2000	-	-	-	1	No
Positive Control	325 ###	52###	94 / 100	107 / 103	No

* x 10⁶

** statistically significant

### highly significant, no statistics performed

Solvent control with Acetone

Table 3:Results of Mammalian Mutagenicity assay (Test 2) with CHO cells

Concentrationµg/ml	Mutant* Frequency	Mutant* Frequency	% Relative cloning eff.	% Relative cloning eff.	Cytotoxicity (yes/no)
-	— MA	+ MA	— MA	+ MA	-
0	3	0	98 / 104	109 / 116	No
0(1 % Acetone)	3	5	100 / 100	100 / 100	No
60	4	-	102 / 106	-	No
100	-	2	-	104 / 103	No
120	6	-	94 / 99	-	No
200	-	0	-	105 / 128	No
300	-	-	0	-	No
500	-	0	-	71 / 124	No
600	3	-	98 / 103	-	No
800	3	-	93 / 102	-	No
900	-	-	-	-	No
1000	-	1	-	56 / 119	No
1200	-	-	-	-	No
1500	-	2	-	7 / 107	No
2000	-	-	-	-	No
Positive Control	306###	124###	84 / 102	110 / 95	No

* x 10⁶

** statistically significant

### highly significant, no statistics performed

Solvent control with Acetone

Applicant's summary and conclusion

Conclusions:

The substance was tested in an in vitro mutagenicity assay in CHO cells, under GLP and following OECD 476. The test substance is non-mutagenic in Chinese Hamster Ovary cells under the conditions of the test.