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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:
key study
Study period:
From January 04,2010 to January 19,2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)
Deviations:
no
Qualifier:
according to
Guideline:
other: Official notice of J MHLW, METI and ME (21 November 2003): YAKUSHOKUHATSU No.1121002 SEIKYOKU No.2 KANPOKIHATSU No. 031121002 Official Notice of J MOL (8 February 1999)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Polynt Lot No. T208210033
- Manufacturing date: 11 Feb 2010
- Expiration date of the lot/batch: 11 Feb 2011

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Keep container tightly closed. Keep in a dry, cool and well ventilated place.
- Storage at testing facility 5 years

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
not specified
Species / strain / cell type:
E. coli WP2 uvr A pKM 101
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
5000 , 1500, 500, 150 , 50 15, 5 µg/plate
Vehicle / solvent:
It was found to be soluble at 154.17 mg/mL in dimethyl sulphoxide (DMSO). The highest concentration of HHPA tested in this study was 50 mg/mL in the chosen vehicle, which provided a final concentration of 5000 μg/plate.
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
without S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
without S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
without S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
without S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoantracene
Remarks:
with S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
with S9
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar

The strains of S. typhimurium were obtained from the National Collection of Type Cultures,London, England.
The strain of E. coli was obtained from the National Collections of Industrial and MarineBacteria, Aberdeen, Scotland.

Aliquots of 0.1 mL of the test substance solutions, positive control or negative control were placed in glass vessels. The negative control was the chosen vehicle, DMSO. S9 mix (0.5 mL) or 0.1 M pH 7.4 phosphate buffer (0.5 mL) was added, followed by 0.1 mL of a 10-hour bacterial culture and 2 mL of agar containing histidine (0.05 mM), biotin (0.05 mM) and tryptophan (0.05 mM). The mixture was thoroughly shaken and overlaid onto previously prepared Petri dishes containing 25 mL minimal agar. Each Petri dish was individually labelled with a unique code, identifying the contents of the dish. Three Petri dishes were used for each treatment. Plates were also prepared without the addition of bacteria in order to assess the sterility of the test substance, S9 mix and sodium phosphate buffer. All plates were incubated at approximately 37C for ca 72 hours. After this period, the appearance of the background bacterial lawn was examined and revertant colonies counted using an automated colony counter (Perceptive Instruments Sorcerer).

As a clear negative response was obtained in the first test, a variation to the test procedure was used for the second test. The variation used was the pre-incubation assay in which the tubes, which contained mixtures of bacteria, buffer or S9 mix and test dilution, were incubated at 37°C for 30 minutes with shaking before the addition of the agar overlay. The maximum concentration chosen was again 5000 µg/plate, but only five concentrations were used.
Evaluation criteria:
For a test to be considered valid, the mean of the vehicle control revertant colony numbers for each strain should lie within or close to the 99% confidence limits of the current historical control range of the laboratory unless otherwise justified by the Study Director. The historical range is maintained as a rolling record over a maximum of five years. Also, the positive control compounds must induce an increase in mean revertant colony numbers of at least twice (three times in the case of strains TA1535 and TA1537) the concurrent vehicle controls. Mean viable cell counts in the 10-hour bacterial cultures must be at least 109/mL.
Statistics:
The mean number and standard deviation of revertant colonies were calculated for all groups. The “fold-increases” relative to the vehicle controls were calculated in order to compare the means for all treatment groups with those obtained for the vehicle control groups.

Results and discussion

Test resultsopen allclose all
Key result
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:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid

Any other information on results incl. tables

The concurrent positive controls demonstrated the sensitivity of the assay and the metabolising activity of the liver preparations. The mean revertant colony counts for the vehicle controls were within or close to the 99% confidence limits of the current historical control range of the laboratory.

Applicant's summary and conclusion

Conclusions:
It is concluded that Hexahydrophthalic anhydride (HHPA) showed no evidence of mutagenic activity in this bacterial system under the test conditions employed.
Executive summary:

Gene mutation has been investigated in bacteria using strains of Salmonella typhimurium and Escherichia coli, in accordance with OECD/EU test methods. Five tester strains TA1535, TA1537, TA98, TA100 and WP2uvrA were used and experiments were performed both in the absence and presence of metabolic activation, using liver S9 fraction from rats pre-treated with phenobarbital and 5,6-benzoflavone. The substance, hexahydrophthalic anhydride (HHPA), did not induce reverse mutation in the tester strains, neither in the absence nor presence of S9 metabolism.