Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2003-12-22 (date test substance was received) to 2005-09-27
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report date:
2005

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
Remarks:
No detailed documentation is provided on test substance, animals, methods and results evaluation
Qualifier:
according to guideline
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
Remarks:
No detailed documentation is provided on test substance, animals, methods and results evaluation
Qualifier:
according to guideline
Guideline:
other: USA EPA, TSCA and FIFRA guidelines and the Japanese METI/MHLW guidelines for testing of new chemical substances.
Deviations:
no
Remarks:
No detailed documentation is provided on test substance, animals, methods and results evaluation
GLP compliance:
no
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
1-acetyl-4-(4-hydroxyphenyl)piperazine
EC Number:
267-744-8
EC Name:
1-acetyl-4-(4-hydroxyphenyl)piperazine
Cas Number:
67914-60-7
Molecular formula:
C12H16N2O2
IUPAC Name:
1-[4-(4-hydroxyphenyl)piperazin-1-yl]ethan-1-one
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material: JNJ-119379-AAA (T001141)
- Physical state: solid (powder)
- Appearance: white powder
Specific details on test material used for the study:
Description: white crystalline solid
Date received: 2003-12-22
Storage conditions: Room temperature, in the dark

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: mean weight of 23.70 g
- Assigned to test groups randomly: no data
- Fasting period before study: no data
- Housing: no data
- Diet: no data
- Water: no data
- Acclimation period: no data

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

IN-LIFE DATES: From: no data To: no data

Administration / exposure

Route of administration:
oral: unspecified
Vehicle:
- Vehicle(s)/solvent(s) used: arachis oil
- Justification for choice of solvent/vehicle: not indicated
- Concentration of test material in vehicle: not indicated
- Amount of vehicle (if gavage or dermal): 10 mL/kg
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:no data
DIET PREPARATION: no data
Duration of treatment / exposure:
Animals were treated once.
Frequency of treatment:
single oral dose
Post exposure period:
Test substance animals and vehicle control animals were sacrificed at 24 and 48 hours after treatment at the high dose group and 24 hours for the two lower dose groups were sacrificed at 24 hours. Positive control animals were sacrificed at 24 hours.
Doses / concentrationsopen allclose all
Dose / conc.:
1 500 other: mg/kg bw
Remarks:
24-hour and 48-Hour Sampling Time
Dose / conc.:
750 other: mg/kg bw
Remarks:
24-hour Sampling Time
Dose / conc.:
375 other: mg/kg bw
Remarks:
24-hour Sampling Time
No. of animals per sex per dose:
7 animals per group and sacrifice time point for the test substance and vehicle control groups, and 5 animals for the positive control group were used.
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide
- Justification for choice of positive control(s): no data
- Route of administration: oral (unspecified)
- Doses / concentrations: 50 mg/kg bw

Examinations

Tissues and cell types examined:
bone marrow erythrocytes: at least 2000 polychromatic erythrocytes (PCEs) per animal were scored for micronuclei.
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: Dose levels were selected on the basis of the results of a range-finding study

TREATMENT AND SAMPLING TIMES (in addition to information in specific fields): single oral administration; sampling 24h and 48h after administration

DETAILS OF SLIDE PREPARATION: The animals were killed at the specified time (24 or 48 hours after treatment), the bone marrow extracted, and smear preparations made and stained.

METHOD OF ANALYSIS: Polychromatic (PCE) and normochromatic (NCE) erythrocytes were scored for the presence of micronuclei.
Evaluation criteria:
no data
Statistics:
No data was provided on the statistical tests performed. However, statistical significance was measured down to p<0.05.

Results and discussion

Test results
Key result
Sex:
male
Genotoxicity:
positive
Toxicity:
yes
Remarks:
hunched posture, ptosis, ataxia and lethargy
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
RESULTS OF RANGE-FINDING STUDY
- Dose range: The study indicated that 1000 mg/kg produced toxicity and 2000 mg/kg bw produced premautre deaths. No further data were provided on the other dose levels were used.
- Solubility: no data
- Clinical signs of toxicity in test animals: Adequate evidence of toxicity was observed in animals dosed with the test substance via the oral route, with a premature death occurring at 2000 mg/kg. Clinical signs were also observed at and above 1000 mg/kg as follows: hunched posture and ptosis.
- Evidence of cytotoxicity in tissue analyzed: no data
- Rationale for exposure: The range-finding test was performed to find suitable dose levels of the test substance for the main study and to investigate to see if there was a marked difference in toxic responses between sexes. There was no marked difference in toxicity of the test substance between sexes; therefore the main test was performed using only male mice.

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei : There were statistically significant increases in the frequency of micronucleated PCEs in all of the test substance dose groups when compared to their concurrent vehicle control groups. The response in the 24-hour groups was inversely dose-related; it was considered that this was due to the high levels of toxicity observed at the upper two test substance dose levels.
- Ratio of PCE/NCE (for Micronucleus assay): There were statistically significant decreases in the PCE/NCE ratio in all of the 24- or 48-hour test substance groups when compared to their concurrent vehicle control groups. This accompanied by the presence of clinical signs was taken to indicate that systemic absorption had occurred, and exposure to the target tissue was achieved.
- The positive control group showed a marked increase in the incidence of micronucleated polychromatic erythrocytes, hence confirming the sensitivity of the system to the known mutagenic activity of cyclophosphamide under the conditions of the test.
- Appropriateness of dose levels and route: The dose levels were chosen based on the results of the range-finding study: 1500 mg/kg bw was the maximum tolerated dose (MTD)
- Statistical evaluation: See the table below.
- Evidence of cytotoxicity: There were no premature deaths seen in any of the dose groups in the main test. Clinical signs were observed in animals dosed with the test material at and above 750 mg/kg in both the 24- and 48-hour groups where applicable; these were as follows: hunched posture, ptosis, ataxia and lethargy.

Any other information on results incl. tables

The group mean results of the micronucleus assay and cytotoxicity are presented below:

 

Micronucleus Results - Summary of Group Mean Data

 

Micronuclei per 2000 PCE

PCE/NCE Ratio

Treatment Group

Group Mean

SD

Group Mean

SD

Vehicle Control (48 h)

1.3

1.3

0.99

0.35

Vehicle Control (24 h)

1.3

1.5

0.95

0.22

Positive Control (24 h)

42.8***

16.3

1.24

0.38

1500 mg/kg (48 h)

24.1***

16.6

0.13***

0.06

1500 mg/kg (24 h)

12.6**

9.9

0.34***

0.07

750 mg/kg (24 h)

14.0***

8.6

0.55***

0.07

375 mg/kg (24 h)

38.0***

12.3

0.64*

0.20

* p<0.05; **p<0.01; *** p<0.0001

 

The test substance was found to produce a statistically significant increase in the frequency of miconuclei in PCEs of mice under the conditions of the test.

Applicant's summary and conclusion

Conclusions:
The test substance was evaluated for induction of micronuclei in the bone marrow of orally treated male mice. The test substance was considered to be genotoxic under the conditions of the test.