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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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline Study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
adopted 26 May 1983
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): p-Chlorobenzaldehyde
- Physical state: white to yellowish crystalline powder
- Molecular weight: 140.6
- Molecular formular: C7H5C10
- Analytical purity: 98.8 %
- Purity test date: 28.08.1990
- Product No.: 028924
- Sample No.: 050484/1990
- Expiration date of the lot/batch: until march 1991
- Storage condition of test material: refrigerator

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
microsomal enzyme systems (S-9 fraction) from Aroclor 1254-induced male Sprague-Dawley rat liver
Test concentrations with justification for top dose:
1st test: 0, 8, 40, 200, 1000, 5000
2nd test: 0, 125, 250, 500, 1000, 2000, 4000

Due to the substance's toxicity, doses ranging from 125 to 4000 µg per plate were chosen for the repeat test.
Vehicle / solvent:
- solvent used: Ethylene glycol dimethylether (EDGE) for the test substance and DMSO for positive controls
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
solvent control
True negative controls:
no
Remarks:
with and without S-9 mix
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
without S9-mix, TA 1535
Positive controls:
yes
Positive control substance:
other: Nitrofurantoin
Remarks:
without S9-mix, TA 100
Positive controls:
yes
Positive control substance:
other: 4-nitro-phenylendiamine
Remarks:
without S9-mix, TA 1537, TA 98
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
with S9-mix, TA 1535, TA 1537, TA 98 and TA 100
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Incubation duration: 48 h at 37°C

NUMBER OF REPLICATIONS: 4

DETERMINATION OF TOXICITY
The toxicity of the test item was assessed in three ways:
a) background growth on the plates for mutant determination
b) marked and dose-dependent reduction in the mutant count per plate compared to the negative control
c) determination of the titer
Evaluation criteria:
Characterization of a substance as positive requires:
- doubling of the spontaneous mutation rate (TA 1535, TA 100, TA 98); threefold increase for TA 1537
- dose-response relationship
- reproducibility of the results

Results and discussion

Test results
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:
> 250 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

p-Chlorobenzaldehyde showed no mutagenic response in any strain with or without S-9 mix.

The test substance showed to produce bacteriotoxic effects at doses above 250 µg/plate. Neverthelesse doses

up to 4000 µg/plate could be used for assessment.

Applicant's summary and conclusion

Executive summary:

In a reverse gene mutation assay the bacteria strains TA 1535, TA 1537, TA 98 and TA 100 of S. typhimurium  were exposed to p-Chlorobenzaldehyde (98.8 %) at concentrations of 0, 8, 40, 125, 200, 250, 500, 1000, 2000, 4000 or 5000 µg/plate (4 plates/dose) in the presence and absence of mammalian metabolic activation.

The test substance showed to produce bacteriotoxic effects at doses above 250 µg/plate. Neverthelesse doses up to 4000 µg/plate could be used for assessment.

The positive controls induced the appropriate responses in the corresponding strains.

There was no evidence mutagenic activty of p-Chlorobenzyaldehyde. No biologically relevant increase in the mutant count, in comparison with the negative controls, waqs observed. Therefore, p-Chlorobenzaldehyde was considered to be non-mutagenic with or without S9 mix.