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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
Study period:
01 Mar 2005 - 10 Oct 2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent

Method

Species / strain
Species / strain:
other: all strains
Metabolic activation:
with and without
Metabolic activation system:
S9 (male Wistar rats induced with 500 mg/kg bw Aroclor 1254 5 days prior to sacrifice
Test concentrations with justification for top dose:
0, 16, 50, 158, 500, 1581 and 5000 ug/plate
Vehicle:
- Vehicle(s)/solvent(s) used: DMSO
- Justification: the test substance is sufficiently soluble in the vehicle
Controls
Negative controls:
no
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Without S9-mix: sodium azide, mitomycin C, cumene hydroperoxide, nitrofurantoin, 4-Nitro-1,2-phenylene diamine; with S9-mix: 2-Aminoanthracene
Details on test system and conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION

Plate incorporation test:
- Exposure duration: 48 hrs

Preincubation test:
- Preincubation period: 20 min
- Exposure duration: 48 hrs

NUMBER OF REPLICATIONS: Two tests, each using three plates per strain per dose


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth by colony count
Evaluation criteria:
A reproducible and dose-related increase in mutant counts of at least one strain is considered to be a positive result. For TA 1535, TA 100 and TA 98 this increase should be about twice that of negative controls, whereas for TA1537, at least a threefold increase should be reached. For TA 102 an increase of about 100 mutants should be reached. Otherwise, the result is evaluated as negative. However, these guidelines may be overruled by good scientific judgment.

Results and discussion

Test results
Species / strain:
other: all strains
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no, but tested up to limit concentrations
Remarks:
Substance precipitation started at 1581 µg/plate, but assessment was deemed possible up to 5000 µg/plate.
Vehicle controls valid:
yes
Negative controls valid:
not examined
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: At 1581 ug/plate and above the substance precipitated. Evaluation was still possible up to and including 5000 ug/plate.

RANGE-FINDING/SCREENING STUDIES: The data from the range-finding study was used as there was no cytotoxicity up to the limit value of 5000 ug/plate and the precipitation did not affect the results. No additional study was performed.

COMPARISON WITH HISTORICAL CONTROL DATA: No "untreated" negative control was set up for the used solvent, since sufficient evidence was available in the literature (e.g. Maron and Ames, 1983) and from historical data.

ADDITIONAL INFORMATION ON CYTOTOXICITY: No cytotoxicity was observed up to the maximum dose of 5000 ug/plate

Any other information on results incl. tables

Table: Maximum number of revertants (means) of all concentrations tested (one result per strain, with the plate concentration between brackets):

 

Control

Test substance (µg/plate)

Strain

-S9

+S9

-S9

+S9

TA 1535

11

12

11 (5000)

12 (500)

TA100

155

193

166 (16)

200 (16)

TA1537

6

10

5 (50)

8 (16)

TA 98

19

34

22 (50)

36 (16)

TA 102

214

250

238 (50)

273 (158)

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative