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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
No data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: OECD and EU guideline study. Unfortunately, a number of pages are missing from the study report, therefore it has not been possible to verify any deviations. On closely-related surrogate.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report date:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
Deviations:
not specified
GLP compliance:
not specified
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): Tetrammine palladium hydrogen carbonate

Test animals

Species:
mouse
Strain:
not specified
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: No data
- Age at study initiation: No data
- Weight at study initiation: group means 26.0-27.7 g
- Assigned to test groups randomly: no data
- Fasting period before study: no data
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data

IN-LIFE DATES: From: To: no data

Administration / exposure

Route of administration:
oral: unspecified
Vehicle:
- Vehicle(s)/solvent(s) used: arachis oil
- Justification for choice of solvent/vehicle: no data
- Concentration of test material in vehicle: no data
- Amount of vehicle (if gavage or dermal): no data
Duration of treatment / exposure:
Animals were given a single oral dose
Frequency of treatment:
Single dose
Post exposure period:
Animals were killed 24 and 48 hours following treatment
Doses / concentrations
Remarks:
Doses / Concentrations:
125, 250, 500 mg/kg bw
Basis:
nominal conc.
No. of animals per sex per dose:
Groups of seven male mice per treatment group; Seven males recieved the vehicle (arachis oil) control; Five males recieved the positive (cyclophosphamide) control.
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide
- Justification for choice of positive control(s): no data
- Route of administration: oral
- Doses / concentrations: 50 mg/kg bw

Examinations

Tissues and cell types examined:
Bone marrow extracted and smear preparations made and stained. Polychromatic and normochromatic erythrocytes scored for the presence of micronuclei.
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: maximum tolerated dose (MTD) was 500 mg/kg bw, in the dose-ranging finding study. Doses of 125 and 250 mg/kg bw were considered appropriate as the two lower dose levels.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Animals were killed 24 or 48 hours later.

DETAILS OF SLIDE PREPARATION: bone marrow extracted and smear preparations made and stained.

METHOD OF ANALYSIS: Polychromatic and normochromatic erythrocytes were scored for the presence of micronuclei
Evaluation criteria:
A statistically significant increase in the frequency of micronucleated PCEs compared to the concurrent vehicle control group was considered evidence of a positive effect.
Statistics:
PCE/NCE ratio

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
yes
Remarks:
Premature deaths were seen in the 24-hour 500 mg/kg bw (2) and 125 mg/kg bw (1) test material groups. Clinical signs were observed in animals dosed with the test material at and above 125 mg/kg bw in both the 24 and 48-hour groups, where applicable.
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
There were no statistically significant increases in the frequency of micronucleated PCEs in any of the test material dose groups when compared to their concurrent vehicle control groups. There were no statistically significant decreases in the PCE/NCE ratio in the 24 or 48-hr test material groups when compared to their concurrent vehicle control groups. However, the presence of premature deaths and clinical observations indicated that systemic absorption had occurred.

There were premature deaths seen in the 24-hr 500 mg/kg bw (two animals) and 125 mg/kg bw (one animal) test material dose groups. Clinical signs were observed in animals dosed with the test material at and above 125 mg/kg bw in both the 24- and 48-hr groups, where applicable. Clinical signs included: hunched posture, ptosis, pilo-erection, lethargy, pallor of the extremities, splayed gait, tiptoe gait, decreased respiratory rate, laboured respiration, ataxia, noisy respiration, gasping respiration, increased lacrimation and increased salivation. It was considered that the loss of animals due to premature death did not effect the integrity of the study, with at least five analysable animals being available per group as recommended in the OECD guidelines.

The positive control group showed a marked increase in the incidence of micronucleated polychromatic erythocytes hence confirming the sensitivity of the system to the known mutagenic activity of cyclophosphamide under the conditions of the test.

Any other information on results incl. tables

Micronucleus study - summary of group mean data:

 TREATMENT GROUP     Number of PCE with micronuclei per 2000 PCE     PCE/NCE ratio
   Group mean  SD  Group mean  SD

Vehicle control

48 -hour sampling time

 1.4  1.7

 1.47

 0.55

Vehicle control

24 -hour sampling time

 1.1  0.7

 1.38

 0.53

Positive control

24 -hour sampling time 

 25.0***  4.6

 1.47

 0.26

Tetrammine palladium hydrogen carbonate

500 mg/kg bw

48 -hour sampling time 

 0.9  0.7

 0.98

 0.58

Tetrammine palladium hydrogen carbonate(a)

500 mg/kg bw

24 -hour sampling time

1.8 

 1.9

 1.67

 1.16

Tetrammine palladium hydrogen carbonate

500 mg/kg bw

24 -hour sampling time

 1.7

 1.5

 1.13

 0.16

Tetrammine palladium hydrogen carbonate(b)

500 mg/kg bw

24 -hour sampling time

 0.5

 0.5

 1.15

 0.58

Key:

PCE = polychromatic erythrocytes

NCE = normochromatic erythrocytes

SD = standard deviation

*** = p<0.001

a = data from five animals

b = data from six animals

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
In an in vivo guideline study, tetraamminepalladium hydrogen carbonate failed to induce a significant increase in the frequency of micronuclei in polychromatic erythrocytes of mice following oral gavage at up to 500 mg/kg bw.
Executive summary:

An in vivo study was performed to assess the potential of tetraamminepalladium hydrogen carbonate to produce damage to chromosomes or aneuploidy when administered orally to mice. The study design complied with OECD Test Guideline 474 and EU Method B12.

 

Following a range-finding study, groups of seven male mice were given 125, 250 or 500 (the MTD) mg/kg bw of the test material and killed 24 or 48 hours later for analysis of micronuclei in polychromatic and normochromatic erythrocytes. Further groups of mice were given arachis oil or cyclophosphamide as vehicle and positive controls, respectively.

 

There was no evidence of a significant increase in the incidence of micronucleated polychromatic erythrocytes in animals dosed with the test material when compared to the concurrent vehicle control groups. No statistically significant decreases in the PCE/NCE ratio were observed in the 24- or 48-hr test material dose groups when compared to their concurrent control groups. However, the presence of premature deaths and clinical signs indicated that systemic absorption had occurred. The positive control material produced a marked increase in the frequency of micronucleated polychromatic erythrocytes, confirming the sensitivity of the test system.

 

In conclusion, tetraamminepalladium hydrogen carbonate failed to induce evidence of chromosome damage following oral gavage at up to 500 mg/kg bw, under the conditions of the test.