tetraammine palladium (II) hydrogen carbonate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study performed between 9 February and 12 March 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: OECD and EU guideline study, to GLP. No details on test material purity and stability. Although no bone marow cytotoxicity observed, premature deaths and clincial signs indicate that systemic absorption had ocurred.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Tetraamminepalladium (II) hydrogen carbonate

IUPAC Name:

Tetraamminepalladium (II) hydrogen carbonate

Constituent 2

Reference substance name:

134620-00-1

Cas Number:

134620-00-1

IUPAC Name:

134620-00-1

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): Tetraamminepalladium hydrogen carbonate

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: DG0475
- Expiration date of the lot/batch: no data
- Purity: no data. Responsibility of sponsor

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark
- Stability under test conditions: no data. Responsibility of sponsor

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: freshly prepared as required as a suspension in arachis oil

Test animals

Species:

mouse

Strain:

CD-1

Details on species / strain selection:

Albino Crl:CD-1 (1CR)BR strain mice

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Ltd, Margate, Kent, UK.
- Age at study initiation: 5-8 weeks
- Weight at study initiation: 24-30 g (group means 26.0-27.7 g)
- Assigned to test groups randomly: yes
- Fasting period before study: no data
- Housing: up to 7 animals in solid-floor polypropylene cages with woodflakes bedding
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-22
- Humidity (%): 50-52
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: From: To: no data

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: arachis oil
- Justification for choice of solvent/vehicle: no data
- Concentration of test material in vehicle: 12.5, 25 or 50 mg/ml
- Amount of vehicle (if gavage or dermal): 10 ml/kg

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: based on MTD from range-finding study

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

OTHER:

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 applicable

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-hr sampling time	1.4	1.7	1.47	0.55
Vehicle control 24-hr sampling time	1.1	0.7	1.38	0.53
Positive control 24-hr sampling time	25.0***	4.6	1.47	0.26
Tetraamminepalladium hydrogen carbonate 500 mg/kg bw 48-hr sampling time	0.9	0.7	0.98	0.58
Tetraamminepalladium hydrogen carbonate(a) 500 mg/kg bw 24-hr sampling time	1.8	1.9	1.67	1.16
Tetraamminepalladium hydrogen carbonate 500 mg/kg bw 24-hr sampling time	1.7	1.5	1.13	0.16
Tetraamminepalladium hydrogen carbonate(b) 500 mg/kg bw 24-hr 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:

In an in vivo study, conducted to OECD guideline and GLP, tetraamminepalladium(II) hydrogen carbonate failed to produce 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(II) hydrogen carbonate to produce damage to chromosomes or aneuploidy when administered orally (by gavage) to mice. The study design complied with OECD Test Guideline 474 and EU Method B12, and was to GLP.

 

Following a range-finding study, groups of seven male mice were administered 125, 250 or 500 (the MTD) mg/kg bw of the test material via gavage 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(II) hydrogen carbonate failed to produce evidence of chromosome damage following oral gavage at up to 500 mg/kg bw, under the conditions of the test.