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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:
19 November 2002 to 16 December 2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study (OECD, EU), to GLP, on the dihydrate

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report date:
2003

Materials and methods

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

Test material

Constituent 1
Reference substance name:
Reference substance 001
Cas Number:
32916-07-7
Details on test material:
- Name of test material (as cited in study report): Palladium(II)nitrate dihydrate
- Substance type: orange-brown powder
- Physical state: solid
- Analytical purity: 40.1% (+/- 0.1%) palladium
- Impurities (identity and concentrations): calcium, copper, iron, magnesium, lead  10 μg/g; silver, gold, iridium, platinum, rhodium, ruthenium  20 μg/g; silicon  30 μg/g
- Composition of test material, percentage of components: - Isomers composition:
- Purity test date: 21 October 2002
- Lot/batch No.: 2403/02-02
- Expiration date of the lot/batch: 21 October 2003
- Stability under test conditions: no data
- Storage condition of test material: room temperature in the dark; stable
- Other: [Please note that the dihydrate has a different CAS RN (32916-07-7) to the anhydrous form (10102-05-3)]

Method

Target gene:
Histidine for S. typhimurium strains; tryptophan for E.coli WP2 uvrA
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 applicable
Species / strain / cell type:
E. coli WP2 uvr A
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9, microsomal fraction derived from Aroclor 1254-induced rat liver. The S9 mix contained 5% (v/v) S9 fraction in the first two studies and 10% (v/v) in the two further studies.
Test concentrations with justification for top dose:
Experiment 1: 3, 10, 33, 100, 333, 1000, 3300 and 5000 μg/plate for TA100 and WP2 uvrA.
Experiment 2: 3, 10, 33, 100, 333 and 666 μg/plate for TA15335, TA1537 and TA98.
Experiment 3: 3, 10, 33, 100 and 250 μg/plate for TA15335, TA1537 and TA98. 3, 10, 33, 100, 333 and 666 μg/plate for TA100 and WP2 uvrA.
Experiment 4: 10, 33, 100, 333 and 666 μg/plate for TA1535 and TA98 with S9 only (since not enough cytotoxicity was seen in experiment 3)
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: soluble after vortexing
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
650 μg/plate for TA100 without S9
Positive control substance:
sodium azide
Remarks:
5 μg/plate for TA1535 without S9
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
10 μg/plate for WP2 uvrA without S9
Positive control substance:
9-aminoacridine
Remarks:
60 μg/plate for TA1537 without S9
Positive control substance:
other: daunomycin
Remarks:
4 μg/plate for TA98 without S9
Positive control substance:
other: 2-aminoanthracene
Remarks:
With 5% S9: 1 μg/plate for TA1535, TA98 and TA100; 2.5 μg/plate for TA1537; 5 μg/plate for WP2 uvrA. With 10% S9: 2.5 μg/plate for TA1535, TA1537, TA98 and TA100; 10 μg/plate for WP2 uvrA
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hr

NUMBER OF REPLICATIONS: plates prepared in triplicate.
Each strain was tested in two independent studies; a further study was performed with TA1535 and TA98 (with S9 only), since insufficient cytotoxicity was observed in one study where the highest dose was 250 μg/plate.

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

OTHER:

Evaluation criteria:
The test substance was considered to be mutagenic if the number of revertant colonies was at least twice that of the spontaneous revertants and reproducible in at least one independently repeated experiment. However any mean plate count of less than 20 revertants was considered to be not significant.

Results and discussion

Test resultsopen allclose all
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:
yes: TA1537, TA100. no: TA1535, TA98
Vehicle controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium, other: TA 1535; TA 98
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: slight precipitation was seen at 3330 and 5000 μg/plate
- Other confounding effects:

RANGE-FINDING/SCREENING STUDIES: yes

COMPARISON WITH HISTORICAL CONTROL DATA: yes and acceptable minimum and maximum numbers of spontaneous revertants and revertants induced by the positive controls given in the report

ADDITIONAL INFORMATION ON CYTOTOXICITY:

Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

In the study with TA1535 and TA98 with S9, a footnote to the table says the vehicle control used was DMSO, but there is no explanation of why and its use is not mentioned in the text.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

In an OECD Test Guideline 471 study, to GLP, palladium dinitrate dihydrate failed to induce an increase in mutation frequency in four Salmonella typhimurium strains (TA1535, TA1537, TA98 and TA100) and Escherichia coli strain WP2 uvr A, either with or without S9, when tested at up to the limits of cytotoxicity.
Executive summary:

The mutagenic potential of palladium dinitrate dihydrate was assessed in a reverse mutagenicity assay, conducted according to OECD Test Guideline 471 and to GLP. The test substance was assessed in four Salmonella typhimurium strains (TA1535, TA1537, TA98 and TA100) and in Escherichia coli WP2 uvrA, in an attempt to detect both base-pair substitution and frameshift mutations.

In a study with strains TA100 and WP2 uvrA (which also served as a range-finding study), without or with 5% S9 fraction in the S9 mix, the test substance precipitated at dose levels of 3330 and 5000 μg/plate. Cytotoxicity was seen at concentrations of 1000 μg/plate and above with TA100, and at 333 or 1000 μg/plate without and with S9, respectively, with WP2 uvrA. When tested with TA1535, TA1537 and TA98, without or with 5% S9 fraction in the S9 mix, at concentrations of up to 666 μg/plate cytotoxicity was seen at levels of 333 μg/plate and above. In a study in which the S9 mix contained 10% S9, cytotoxicity was observed in all the test strains, both with and without metabolic activation, apart from TA1535 and TA98 in the presence of S9 only. Since the highest dose used for these latter strains was only 250 μg/plate, a further experiment was performed in which the top dose was 666 μg/plate; toxicity was observed for both strains.

Palladium dinitrate dihydrate did not cause an increase in mutation in these studies, either with or without S9. In contrast, the known mutagens used as positive controls showed the expected mutagenic activity