Gadoliniumsulfite trihydrate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 February 2003 - 27 May 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Gadoliniumsulfite trihydrate

EC Number:

456-900-2

EC Name:

Gadoliniumsulfite trihydrate

Cas Number:

51285-81-5

Molecular formula:

Gd2(SO3)3*3H2O

IUPAC Name:

digadolinium(3+) trihydrate trisulfite

Test material form:

solid: particulate/powder

Details on test material:

Off white, crystalline powder
Batch number FSG 3896 or 02-FW-095

Method

Target gene:

TA 98 (his D 3052, uvrB, rfa + R-factor)
TA 100 (his G 46, uvrB, rfa + R-factor)
TA 102 (his G 428, rfa + R-factor)
TA 1535 (his G 46, uvrB, rfa)
TA 1537 (his C 3076, uvrB, rfa)

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Details on mammalian cell type (if applicable):

The Salmonella strains TA 98, TA 100, and TA 1535 were obtained from B.
N. Ames, University of Berkeley, California, USA, on August 15, 1985. Salmonella
typhimurium TA 102 was obtained from B. Diener, Institute of Toxicology,
University of Mainz, Germany, on June 24, 1992. Salmonella strain
TA 1537 was obtained from J. Hengstler, Institute of Toxicology, University
ofMainz, Germany, on December 8, 2000.

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Details on mammalian cell type (if applicable):

Escherichia coli WP2 uvrA was distributed by the National Collections of Industrial
& Marine Bacteria Ltd., Aberdeen, Scotland (NCIMB 11188 from
Aug. 18, 1977) and obtained from H. Träger, Knall AG, Ludwigshafen, Germany,
on December 23, 1994.

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

5.00, 15.8, 50.0, 158, 500, 1580 and 5000 µg per plate
The test material concentrations used were selected according to the EEC and OECD guidelines for this test system and the requirements ofthe Labor Ministry ofJapan. If the test material is soluble in the solvent of choice it should be investigated in the first experimental series at seven concentrations, separated by half-log intervals (i.e. a factor of root 10), ranging from 5 to 5000 µg per plate. In the second experimental series, usually 5 concentrations including at least 4 nontoxic concentrations should be tested. Signs of toxicity to the bacteria are a reduction in the number of spontaneaus revertants or a clearing of background lawn of non-revertant bacteria. Precipitation of the test material, if it occurs, should not interfere with scoring of the colonies. Depending upon the precipitation characteristics of the test material and toxicity data ascertained in the first series, high concentrations may be omitted or lower concentrations may additionally be tested in the second experimental series.

Vehicle / solvent:

0.5n HCl for the highest testmaterial concentration further diluted with distilled water for the next lower concentrations.

Controls

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

N-ethyl-N-nitro-N-nitrosoguanidine

benzo(a)pyrene

cumene hydroperoxide

other: 2-aminoanthracene

Details on test system and experimental conditions:

Preparation of bacteria suspension
Fresh suspensions of the tester strains were prepared for each day's experiments. For each strain, 100 mL Standard I Nutrient Broth were inoculated by 500 µg/L of a frozen permanent culture and incubated overnight in a + 37°C shaking incubator. For the Refactor strains, ampicillin was added to the nutrient broth (25 µg/mL). S. typhimurium TA 102 was incubated overnight in the presence of 200 µg tetracycline per 100 mL nutrient broth. Cell density of the overnight cultures was checked by measuring the optical density of the cell suspensions and corrected if necessary. The suspensions were then maintained at ice-bath temperature until use.

Technique for testing
Salmonella typhimurium and Escherichia coli strains were tested in accordance with the plate incorporation method described by Ames et al. (1975) and the OECD and EEC guidelines for this test system. The methods were extensively harmonized to follow the requirements of the Labor Ministry of Japan - Notification dated June 13, 1979 and the Notification No. 1-24 of the Pharmaceutical Affairs bureau, Ministry of Health and Welfare, dated September 11, 1989.

Number of plates used:
3 parallel plates were used for each concentration step of the test material and the positive controls. Twice as many solvent control plates were used for each bacterial strain.
Type of plates used:
Commercially available Glucose-Agar plates were used for all strains except for S. typhimurium strain TA 102. Forthat strain, Minimal-Glucose plates were self-plated using DIFCO Agar (DIFCO 0140-01).

Results and discussion

Test results

Test results 1

Key result

Species / strain:

other: S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

Toxicity to the bacteria was observed at the highest concentration tested, i.e. 5000 µg/plate.

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

Toxicity to the bacteria was observed at the highest concentration tested, i.e. 5000 ug/plate.

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

With and without addition of S9 mix as the external metabolizing system Gadoliniumsulfite trihydrate was not mutagenic under the experimental conditions described.

Executive summary:

The investigations for mutagenic potential were performed using Salmonella typhimurium tester strains TA 98, TA 100, TA 102, TA 1535 and TA 1537, and Escherichia coli WP2 uvrA. The plate incorporation test with and without addition of liver S9 mix from Aroclor 1254-pretreated ratswas used. Two independent experimental series were performed. In the two series with S9 mix, 10 % and 30 % S9 in the S9 mix were used in the 1st and 2nd series, respectively. For the highest testmaterial concentration, Gadoliniumsulfite trihydrate was dissolved in 0.5n HCl, and it was further diluted with distilled water for the next lower concentrations. It was tested at concentrations ranging from 5.00 to 5000 µg/plate. Precipitation of the test material on the agar plates occurred at concentrations >= 1580 µg/plate or at 5000 µg/plate, depending upon the experimental condition. Taxicity to the bacteria was observed at the highest concentration tested, i.e. 5000 µg/plate. Daunomycin, N-ethyl-N'-nitro-N-nitrosoguanidine, 9-aminoacridine and cumene hydroperoxide served as strain specific positive control test materials in the absence of S9 mix. 2-Aminoanthracene and benzo[a]pyrene were used for testing the bacteria and the activity of the S9 mix. Each treatment with the test materials used as positive controls led to a clear increase in revertant colonies, thus, showing the expected reversion properties of all strains and good metabolic activity ofthe S9 mix used. With and without addition of S9 mix as the external metabolizing system, Gadoliniumsulfite trihydrate was not mutagenic under the experimental conditions described.