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Toxicological information

Genetic toxicity: in vitro

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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restrictions. Restrictions: no details about the purity of the test substance.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
2001
Reference Type:
publication
Title:
Toxicity assessment of thiodiglycol
Author:
Reddy G, Major MA, Leach GJ
Year:
2005
Bibliographic source:
Int J Toxicol 24:435–442

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Principles of method if other than guideline:
adopted 1997
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Lot No. 05701EQ;
Date received: February 28, 2001
(further data available from the sponsor)

Method

Target gene:
His-
and in E. coli Trp-
Species / strain
Species / strain / cell type:
other: Salmonella typhimurium TA98, TA100, TA1535, TA1537 and E. coli WP2uvrA
Metabolic activation:
with and without
Metabolic activation system:
S9 fraction from liver homogenates of rats (induced with i.p. 500 mg/kg Aroclor 1254) plus cofactors
Test concentrations with justification for top dose:
0, 33, 100, 333, 1000, 3330, 5000 µg/plate
Vehicle / solvent:
water (Quality Biological Lot No. 708589)
Controls
Untreated negative controls:
other: sterility control
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: see freetext
Details on test system and experimental conditions:
Positive control:
with MA: 2.5 µg/plate benzo(a)pyrene for TA98, 2,5 µg/plate 2-aminoanthracene for TA100, TA1535, TA1537 and 25 µg/plate 2-amino-anthracene for WP2uvrA; without MA: 1.0 µg/plate 2-nitrofluorene for TA98, 2 µg/plate sodium azid for TA100 and TA 1535, 2 µg/plate ICR-191 for TA1537, 1 µg/plate 4-nitroquinoline-N-oxide for WP2uvrA.

SYSTEM OF TESTING
- 2 independent trials; in the 1st and 2nd trial the plate incorporation method was used; 3 plates per concentration; S9-mix and dilutions prepared immediately prior to use

- Cytotoxicity:
A preliminary toxicity test was performed to define the concentrations to be used for the mutagenicity study. TA100 and E. coli WP2uvrA exposed to 10 dose levels between 6.67 and 5000 µg/plate with and without MA; cytotoxicity evaluated by scoring the decrease in revertants and/or a thinning or disappearance of the bacterial background lawn (no cytotoxic effects detected); in the main study cytotoxicity scored in the same manner.
Evaluation criteria:
- tester strain integrity and strain culture density demonstrated
- negative and positive controls within the range of historical controls
- positive controls exhibited at least 3-fold increase in revertants over vehicle control
- positive: in TA98, TA100, and WP2uvrA at least 2-fold increase in revertants accompanied by a dose response to increasing concentrations;
- same with TA1535 and TA1537 but increase in revertants at least 3-fold
Statistics:
Means +- standard deviation (SD) calculated

Results and discussion

Test results
Species / strain:
bacteria, other: Salmonella typhimurium TA98, TA100, TA1535, TA1537 and E. coli WP2uvrA
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
Positive controls validity:
valid
Additional information on results:
TEST SUBSTANCE HANDLING
- up to the high dose level the TS formed a transparent colorless solution without precipitates
CYTOTOXICITY IN PRELIMINARY TEST
- no cytotoxic effects detected at any dose level
GENOTOXIC EFFECTS IN THE MAIN STUDY
- thiodiglycol did not induce any significant increase in the number of revertants, with or without S9 mix, in any of the 5 strains tested (see Table below)
- Negative (compared to historical controls) and positive controls were valid .
- no cytotoxicity detected at any dose level
Remarks on result:
other: other:
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Mutagenic activity of thiodiglycol in the Ames test

Mean number of revertants/plate +- standard deviation

Dose level in µg/plate

TA 98

TA 100

TA1535

TA1537

WP2uvrA

Plate incorporation test I without S9-mix

Range in historical Vehicle controls

6 - 32

57 - 145

3 - 23

1 - 21

6 - 30

0

18+-5

105+-15

14+-5

7+-2

17+-1

33.3

23+-1

95+-18

17+-3

5+-2

20+-4

100

22+-7

107+-18

14+-7

6+-5

22+-4

333

25+-4

85+-7

13+-2

8+-4

21+-3

1000

22+-2

89+-8

12+-3

9+-1

25+-4

3330

22+-5

101+-6

11+-1

6+-3

23+-7

5000

18+-3

89+-8

10+-2

5+-4

23+-5

Positive control

209+-27

1420+-52

1075+-22

864+-16

142+-13

-

Plate incorporation test I with S9-mix

Range in historical Vehicle controls

7 - 48

62 - 164

4 - 27

2 - 26

6 - 48

0

27+-5

127+-9

14+-6

11+-2

19+-5

33.3

31+-3

122+-14

15+-4

10+-2

24+-5

100

31+-3

135+-6

12+-2

14+-3

25+-4

333

23+-4

123+-7

14+-4

12+-3

27+-2

1000

26+-3

119+-9

15+-3

12+-4

24+-3

3330

34+-6

117+-9

23+-9

9+-3

29+-1

5000

24+-6

115+-5

12+-2

8+-2

26+-6

Positive control

297+-12

899+-79

155+-12

100+-7

472+-52

-

Plate incorporation test II without S9-mix

Range in historical Vehicle controls

6 - 32

57 - 145

3 - 23

1 - 21

6 - 30

0

30+-8

110+-5

16+-5

10+-5

26+-9

33.3

33+-6

107+-3

16+-2

11+-3

40+-7

100

30+-4

107+-10

15+-4

9+-1

35+-6

333

37+-8

112+-5

16+-2

13+-6

30+-2

1000

33+-17

105+-6

17+-8

14+-3

29+-4

3330

32+-7

113+-21

16+-9

9+-3

28+-2

5000

33+-10

113+-13

11+-5

11+-4

26+-5

Positive control

297+-37

1557+-66

1257+-27

710+-77

150+-17

-

Standard plate test II with S9-mix

Range in historical Vehicle controls

7 - 48

62 - 164

4 - 27

2 - 26

6 - 48

0

46+-1

127+-14

16+-3

12+-3

23+-5

33.3

56+-10

137+-6

15+-3

17+-5

29+-1

100

50+-4

128+-20

19+-8

17+-5

26+-5

333

54+-5

127+-10

14+-2

17+-6

31+-5

1000

44+-1

131+-14

16+-7

8+-3

26+-2

3330

54+-5

131+-12

18+-5

19+-2

33+-5

5000

54+-3

145+-6

17+-2

10+-6

19+-2

Positive control

420+-33

968+-40

161+-14

123+-8

516+-59

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test substance did not cause an increase in the mean number of revertants per plate with any of the tester strains in the presence or absence of a metabolic activation system at dose levels up to 5 mg/plate.
Executive summary:

Guideline study with acceptable restrictions (no details about the purity of the TS).

S. typhimurium strains TA98, TA100, TA1535 and TA1537 and E. coli strain WP2uvrA were exposed in the presence and absence of S9 -mix to 33.3, 100, 333, 1000 , 3330 and 5000 μg per plate along with concurrent vehicle and positive controls, using three plates per dose. No increase in revertants was found even at the recommended max. dose of 5000 µg/plate (see OECD 471). No cytotoxic effects were detected. The results of the initial mutagenicity assay were confirmed in an independent 2nd trial.

Conclusion: The test substance did not cause an increase in the mean number of revertants per plate with any of the tester strains in the presence or absence of a metabolic activation system at dose levels up to 5 mg/plate.