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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:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
Data is from peer reviewed publication

Data source

Reference
Reference Type:
publication
Title:
Salmonella Mutagenicity Tests: II. Results From The Testing Of 270 Chemicals
Author:
Mortelmans,K, Haworth,S, Lawlor,T, Speck,W, Tainer,B And Zeiger,E
Year:
1986
Bibliographic source:
Environ. Mutagen. 8(Suppl. 7):1 -119, 1986

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
Gene mutation toxicity study was performed for Formamide to evaluate its mutagenic nature
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Ethanamide
Cas Number:
75-12-7
Molecular formula:
CH3NO
IUPAC Name:
Ethanamide
Details on test material:
- Name of test material: Formamide
- IUPAC name: Ethanamide
- Molecular formula: CH3NO
- Molecular weight: 45.0407 g/mol
- Substance type: Organic
Specific details on test material used for the study:
- IUPAC name: Ethanamide
- Molecular formula: CH3NO
- Molecular weight: 45.0407 g/mol
- Substance type: Organic
- Physical state: No data
- Purity: 98%
- Impurities (identity and concentrations): 2%

Method

Target gene:
Histidine
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not specified
Cytokinesis block (if used):
No data
Metabolic activation:
with and without
Metabolic activation system:
Male Sprague-Dawley rats and male Syrian hamsters were routinely used for the S9 preparation of the liver fractions
Test concentrations with justification for top dose:
Lab 1: 0, 33, 100, 333, 1000, 3333 or 10000 µg/plate
Lab 2: 0, 100, 333, 1000, 333 or 10000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Water
- Justification for choice of solvent/vehicle: The test chemical was soluble in water
Controls
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
yes
Remarks:
Water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
9-aminoacridine
sodium azide
other: 4-nitro-o-phenylenediamine (TA98; -S9), 2-aminoanthracene (all strains, +S9)
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 mins
- Exposure duration: 48 hr
- Expression time (cells in growth medium): 48 hr
- Selection time (if incubation with a selection agent): No data
- Fixation time (start of exposure up to fixation or harvest of cells): No data

SELECTION AGENT (mutation assays): No data
SPINDLE INHIBITOR (cytogenetic assays): No data
STAIN (for cytogenetic assays): No data

NUMBER OF REPLICATIONS: At least five dose levels of the chemicals were tested, with three plates per dose level.

NUMBER OF CELLS EVALUATED: No data

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: No data

OTHER EXAMINATIONS:
- Determination of polyploidy: No data
- Determination of endoreplication: No data
- Other: No data

OTHER: No data
Rationale for test conditions:
No data
Evaluation criteria:
1) mutagenic response: a dose-related, reproducible increase in the number of revertants over background, even if the increase was less than twofold;
2) nomutagenic response: when no increase in the number of revertants was elicited by the chemical;
3) questionable response: when there was an absence of a clear-cut dose-related increase in revertants; when the dose-related increases in the number of revertants were not reproducible;
or when the response was of insufficient magnitude to support a determination of mutagenicity
Statistics:
Mean and Standard error of mean

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA100, TA1535, TA1537, TA98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: No data
- Effects of osmolality: No data
- Evaporation from medium: No data
- Water solubility: No data
- Precipitation: No data
- Other confounding effects: No data

RANGE-FINDING/SCREENING STUDIES: The chemical was initially tested with strain TA100 in the presence and the absence of the metabolic activation systems, over a wide dose range with an upper limit of 10 mg/plate, or less when solubility problems were encountered. Toxicity was evidenced by one or more of the following phenomena: appearance of his+ pinpoint colonies, reduced numbers of revertant colonies per plate, or thinning or absence of the bacterial lawn. Nontoxic chemicals were tested in the initial experiment up to the 10 mg/plate dose level, or to a level determined by their solubility. Toxic chemicals were tested up to a high dose which exhibited some degree of toxicity.

COMPARISON WITH HISTORICAL CONTROL DATA: No data
Remarks on result:
other: No mutagenic potential

Any other information on results incl. tables

Table: Mutation data for the test chemical Formamide

LAB 1:

Dose (µg/plate)

TA100

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

85

2.1

107

11.0

110

23.7

33

76

3.4

 

 

 

 

100

73

0.7

115

14.4

110

14.7

333

75

2.1

108

10.6

140

11.1

1000

77

4.0

106

9.9

131

8.1

3333

72

1.5

117

1.5

144

11.1

10000

 

 

107

4.0

120

9.2

Positive control

1499

90.4

2677

145.0

2356

381.3

 

Dose (µg/plate)

TA1535

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

7

1.5

7

1.2

8

0.7

33

3

0.6

 

 

 

 

100

5

2.2

5

1.5

5

0.3

333

3

0.3

5

1.2

4

1.5

1000

4

1.2

5

0.6

3

1.5

3333

2

0.7

7

1.2

4

0.7

10000

 

 

11

2.9

5

0.3

Positive control

601

18.5

87

15.4

77

39.2

 

Dose (µg/plate)

TA1537

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

5

0.7

8

1.7

10

2.6

33

6

0.3

 

 

 

 

100

4

1.0

4

0.9

4

1.2

333

5

1.5

7

0.7

6

0.7

1000

4

1.0

3

0.0

3

0.9

3333

5

2.3

7

1.8

7

1.7

10000

 

 

5

0.7

3

0.3

Positive control

777

33.2

95

31.9

145

12.2

 

Dose (µg/plate)

TA98

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

14

1.0

17

2.7

15

1.5

33

13

1.2

 

 

 

 

100

14

2.2

16

1.5

21

3.1

333

16

1.5

13

0.7

23

2.4

1000

17

1.7

117

1.7

12

0.7

3333

16

2.0

22

1.5

13

1.5

10000

 

 

17

1.9

21

1.5

Positive control

692

56.0

2121

298.9

898

47.1

 

LAB 2:

Dose (µg/plate)

TA100

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

137

6.4

107

5.7

125

3.1

100

137

6.1

94

4.0

117

6.7

333

145

11.7

99

5.8

114

8.7

1000

136

5.8

133

6.7

116

5.2

3333

131

4.6

107

8.7

118

6.5

10000

143

7.8

107

14.7

114

6.7

Positive control

1265

37.3

865

14.6

1402

15.0

 

Dose (µg/plate)

TA1535

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

31

1.8

17

2.7

11

1.0

100

35

2.6

11

1.5

16

0.7

333

40

3.4

13

1.3

12

2.2

1000

36

2.1

14

1.9

12

1.6

3333

35

4.3

10

2.0

12

1.9

10000

33

4.7

11

3.2

13

2.2

Positive control

958

11.9

126

11.2

135

7.2

 

Dose (µg/plate)

TA1537

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

10

0.9

12

2.1

13

1.3

100

7

2.0

15

1.5

7

1.7

333

9

0.3

11

1.8

9

1.7

1000

8

1.2

10

0.3

9

4.4

3333

9

1.2

11

2.5

10

0.9

10000

7

0.7

8

0.7

8

0.6

Positive control

198

11.4

92

2.8

173

8.1

 

Dose (µg/plate)

TA98

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

18

2.7

36

2.9

40

2.7

100

20

3.5

36

5.7

37

1.9

333

20

1.7

34

1.0

30

3.0

1000

14

0.6

36

4.0

33

1.7

3333

21

3.1

35

2.6

32

2.9

10000

16

2.6

36

1.9

33

3.7

Positive control

1801

97.8

961

53.3

1598

53.8

 

Applicant's summary and conclusion

Conclusions:
Formamide did not induce mutation in the Salmonella typhimurium strain TA100, TA1535, TA1537, TA98 both in the presence and absence of S9 metabolic activation system and hence the chemical is not likely to classify as a gene mutant in vitro.
Executive summary:

Gene mutation toxicity study was performed for formamide to evaluate its mutagenic nature. The study was performed as per the preincubation protocol using Salmonella typhimurium strain TA100, TA1535, TA1537, TA98 both in the presence and absence of S9 metabolic activation system at doses of 0, 33, 100, 333, 1000, 3333 or 10000µg/plate in lab 1 and 0, 100, 333, 1000, 3333 or 10000µg/plate in lab 2. Water was used as the vehicle. The plates were incubated for 48 hrs after 20 mins preincubation before the evaluation of the revertant colonies could be made. Formamide did notinduce mutation in the Salmonella typhimurium strain TA100, TA1535, TA1537, TA98 both in the presence and absence of S9 metabolic activation system and hence the chemical is not likely to classify as a gene mutant in vitro.