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Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
2010-04-09 to 2010-05-21
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP - Guideline study, tested with the source substance CAS 111-82-0. According to the ECHA guidance document ¿Practical guide 6: How to report read-across and categories (March 2010)¿, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Constituent 1
Reference substance name:
Methyl laurate
EC Number:
203-911-3
EC Name:
Methyl laurate
Cas Number:
111-82-0
IUPAC Name:
methyl laurate
Details on test material:
- Name of test material (as cited in study report): Methyl Laurate, Notox substance 202170/A
- Physical state: clear colourless liquid
- Analytical purity: 99.33%
- Lot/batch No.: SME02/1301/K
- Expiration date of the lot/batch: 1 February 2011
- Storage condition of test material: stable at RT in the dark under nitrogen

Method

Species / strain
Species / strain / cell type:
lymphocytes: cultured peripheral human lymphocytes
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9-mix
Test concentrations with justification for top dose:
3h treatment: 33, 100 and 200 µg/mL
24h treatment: 100, 120 and 140 µg/mL
48h treatment: 30, 120 and 140 µg/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Ethanol
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Ethanol
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
with rat liver S9-mix

Migrated to IUCLID6: 10 µg/mL
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Ethanol
True negative controls:
no
Positive controls:
yes
Positive control substance:
mitomycin C
Remarks:
without rat liver S9-mix

Migrated to IUCLID6: 0.5 µg/mL for a 3 h exposure period, 0.2 µg/mL for a 24 h exposure period and 0.1 µg/mL for a 48 h exposure period
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 3, 24 and 48h
- Fixation time (start of exposure up to fixation or harvest of cells): 3h treatment: 24 and 48h; 24h treatment: 24h; 48h treatment: 48h

SPINDLE INHIBITOR (cytogenetic assays): colchicine 0.5 µL/mL medium
STAIN (for cytogenetic assays): Giemsa 5% (v/v) in tap water

NUMBER OF REPLICATIONS: 2

NUMBER OF CELLS EVALUATED: 100 per culture

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index of 1000 cells

OTHER EXAMINATIONS:
- Determination of polyploidy: yes
Evaluation criteria:
A test substance was considered positive (clastogenic) in the chromosome aberration test if: a) It induced a dose-related statistically significant (Chi-square test, one-sided, p < 0.05) increase in the number of cells with chromosome aberrations. b) A statistically significant and biologically relevant increase in the frequencies of the number of cells with chromosome aberrations was observed in the absence of a clear dose-response relationship.
A test substance was considered negative (not clastogenic) in the chromosome aberration test if none of the tested concentrations induced a statistically significant (Chi-square test, one-sided, p < 0.05) increase in the number of cells with chromosome aberrations. The preceding criteria are not absolute and other modifying factors might enter into the final evaluation decision.
Statistics:
Chi-square test, one-sided, p < 0.05

Results and discussion

Test results
Species / strain:
lymphocytes: cultured human peripheral lymphocytes
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: At a concentration of 200 µg/mL methyl laurate precipitated in the culture medium
- Polyploidy did also not occur in a significant way also high controls showed positive results
RANGE-FINDING/SCREENING STUDIES: The highest concentration analysed was selected based on the solubility of the test substance in the culture medium (3 h and 24 h continuous exposure) or on toxicity, inhibition of the mitotic index of about 50% or greater (48 h continuous exposure).

Any other information on results incl. tables

 Table 1: Cytotoxic and Genotoxic observations

Test item

Concentration

Mitotic Index

Aberrant cells in %

 

in µg/mL

in %

with gaps

without gaps

Exposure period 3h, fixation time 24h, without S9 mix

Ethanol

1.0% (v/v)

100

1

1

MMC

0.5

64

58

58

Test substance

33

90

0

0

100

75

4

3

200

66

4

3

Exposure period 3h, fixation time 24h, with S9 mix

Ethanol

1.0% (v/v)

100

1

1

CP

0.5

54

42

42

Test substance

3

100

1

0

10

89

2

2

33

66

1

0

Exposure period 24h, fixation time 24h, without S9 mix

Ethanol

1.0% (v/v)

100

4

3

MMC

0.2

54

71

69

Test substance

3

99

0

0

10

80

5

4

33

42

5

4

Exposure period 48h, fixation time 48h, without S9 mix

Ethanol

1.0% (v/v)

100

2

1

MMC

0.1

102

60

59

Test substance

3

93

0

0

10

59

1

1

33

44

2

1

Exposure period 3h, fixation time 48h, with S9 mix

Ethanol

1.0% (v/v)

100

2

2

CP

10.0

--

52

51

Test substance

3

103

2

1

10

101

2

1

33

106

0

0

                    MMC: Mitomycin           CP: Cyclophosphamide

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative