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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-03-04 to 2002-09-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 102
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver S9
Test concentrations with justification for top dose:
31.6-3160 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO

- Justification for choice of solvent/vehicle: Solvent is not harmful to bacteria
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535, TA 100 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
TA 98 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
TA 102 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
TA 98, TA 102, TA 1537 (with activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
TA 1537 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-anthracene amide
Remarks:
TA 98, TA 102, TA 1537 (with activation)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar, standard plate incorporation method, preincubation method

DURATION
- Preincubation period: 60 minutes
- Exposure duration: 48 hours

SELECTION AGENT (mutation assays): histidine deficient agar

NUMBER OF REPLICATIONS: cells were plated in triplicate; the experiment was repeated using the pre-incubation method.

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

ACTIVATION:
Aroclor induced rat liver S9 (protein content 32.92 mg/ml, cytochrome P-450: 0.32 nmol/mg) was added to S9 mix so that the mix contained 5% S9. glucose-6-phophate and NADP were added as co-factors. 0.5 ml S9 mix was added to 2 ml of top agar to a total volume of 2.7 ml. Final concentration S9 in agar was therefore approximately 1%.



Evaluation criteria:
The number of revertants is significantly increased compared with the solvent control to at least 2 fold of the solvent control for TA98, TA100 and TA102 and 3 fold of the solvent control for TA 1535 and TA1537 in both independent experiments. Positive results have to be reproducible and the histidine independence of the revertants has to be confirmed by streaking random samples on histidine free agar plates.
Statistics:
MANN and WHITNEY and Spearman's rank correlation used.

Results and discussion

Test resultsopen allclose all
Key result
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:
cytotoxicity
Remarks:
3160 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
3160 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
See tables 2-4.

COMPARISON WITH HISTORICAL CONTROL DATA: Controls were within range of historical controls


Any other information on results incl. tables

Table 2: Dose range-finding study Number of revertants per plate (2 plates)

 

TA100

Conc.
(µg/plate)

Plate 1

Plate 2

Cytotoxic
(yes/no)

0*

133

142

No

0.316

122

143

No

1

141

145

No

3.16

149

136

No

10

120

129

No

31.6

105

128

No

100

108

106

No

316

103

111

No

1000

134

133

No

3160

104

112

Yes

5000

131

109

Yes

*solvent control with DMSO

Table 3: Experiment 1 Plate incorporation Number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA102

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

28.3

29.3

No

163

146.7

No

288

286.3

No

31.6

32

30.3

No

142.7

158.7

No

281

284.7

No

100

28.3

36.7

No

153

147.7

No

290.7

279.3

No

316

33.7

34

No

147.7

162.7

No

276.3

299.7

No

1000

34

38

No

158.3

146.3

No

297.3

292.7

No

3160

39.3

35

Yes

164

156.7

Yes

295.7

273.3

Yes

Positive control

1003

994

No

1312.3

1298.7

No

1313.7

1305

No

*solvent control with DMSO

Table 3: Experiment 1 Plate incorporation Number of revertants per plate (mean of 3 plates)

 

TA1535

TA1537

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

12

12.7

No

4.7

6

No

31.6

13.7

11.7

No

3

7

No

100

11.7

13

No

5.3

6.3

No

316

12.3

12

No

5

7.7

No

1000

11

12

No

7

8

No

3160

11.7

11

Yes

8.3

9

Yes

Positive control

773.3

780

No

780

783.7

No

*solvent control with DMSO

Table 4: Experiment 2 Preincubation Number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA102

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

33

41.3

No

117.7

141.7

No

274.3

298.7

No

31.6

45

43.7

No

115

138.7

No

278.3

272.7

No

100

37.7

42

No

132

138

No

274.3

279.7

No

316

36.3

38.7

No

133.7

141.7

No

298.7

265

No

1000

34

44.3

No

120.3

145

No

268.3

278

No

3160

0

0

yes

0

0

yes

0

0

yes

Positive control

1070

1059

No

1199.7

1211

No

1176.7

1214

No

*solvent control with DMSO

Table 4: Experiment 2 Preincubation Number of revertants per plate (mean of 3 plates)

 

TA1535

TA1537

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

11.7

11.3

No

3

3

No

31.6

12

10.7

No

2.3

4

No

100

11

11.3

No

3.3

3

No

316

11

12

No

3

4

No

1000

11

12

No

3

3.7

No

3160

0

0

yes

0

0

yes

Positive control

646.3

624.3

No

640.7

637.7

No

*solvent control with DMSO

Applicant's summary and conclusion

Conclusions:
Trichloro(propyl)silane has been tested for mutagenicity to bacteria according to OECD TG 471 and under GLP conditions in Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537. No evidence of an increase in the number of revertants was observed for the test substance when tested up to cytotoxic concentrations with and without metabolic activation in any of the test strains in either the initial plate incorporation assay or the subsequent pre-incubation test. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of test.