Registration Dossier

Toxicological information

Genetic toxicity: in vivo

Currently viewing:

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
other: experimental resulta on similar substance
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Mollegard Deutshland
- Number: 85 (50 male and 35 female)
- Age at study initiation: between 6 and 8 weeks
- Weight at study initiation: 27-48 g for male, 23-37 g for female
- Housing: mouse were housed in Macrolon Type 2 cages in optimal hygienic conditions.
- Diet: Granular Altromin N 1326
- Water: municipal water ad libitum
- Acclimation period:at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 55 ± 10 %
- Air changes (per hr): 10 times/h
- Photoperiod: 12 h light / 12 h dark

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Acqueous solution of ultra - amylopectin (0.7%) with the addiction of two drops of Tween 80 (polysorbate) per 10 ml of solution.
Details on exposure:
single oral administration for the tested item
single oral administration for the negative control
single intraperitoneal application for the positive control
Duration of treatment / exposure:
one single application
Frequency of treatment:
single oral administration for the tested item
single oral administration for the negative control
single intraperitoneal application for the positive control
Post exposure period:
24 h and 48 h
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
1600 mg/kg
Basis:
nominal in water
Remarks:
Doses / Concentrations:
800 mg/kg
Basis:
nominal in water
Remarks:
Doses / Concentrations:
400 mg/kg
Basis:
nominal in water
Remarks:
Doses / Concentrations:
1200 mg/kg
Basis:
nominal in water
No. of animals per sex per dose:
Dose 1600 mg/kg: Observation time: 48 h, 5 male and 5 female
Dose 1600 mg/kg: Observation time: 24 h, 5 male and 5 female
Dose 800 mg/kg: Observation time: 24 h, 5 male and 5 female
Dose 400 mg/kg: Observation time: 24 h, 5 male and 5 female
Dose 1200 mg/kg: Observation time: 24 h, 5 male and 5 female

Positive control: Dose 80 mg/kg, Observation time: 24 h, 5 male and 5 female





Control animals:
yes
Positive control(s):
Name: cyclophosphamide
Supplier: SIGMA CHMIE Gmbh
- Route of administration: intraperitoneal
- Doses / concentrations: 80 mg/kg
- Application volume: 0.1 ml/10 g body weight
- Solvent: water for injection

The preparations of the positive control substance were freshly prepared before administration.

Examinations

Tissues and cell types examined:
The cells suspension was obtained from the extraction of bone marrow from the medullary canal of femurs.
Details of tissue and slide preparation:
The cells suspension was treated and the specimens colored following Pappenheimer's method.
2000 polychromatic erythrocytes per animal were examined microscopically in order to determine the presence and the number o micronuclei.




Evaluation criteria:
The classification of micronuclei was performed using the following criteria:
- Micronuclei are round, rarely oval or crescent shaped.
- They have a sharp contour.
- They are uniformly colored and are approximately from 1/20 to 1/5 of the diameter of the erythrocytes.
- It is usually only a micronucleus present.
The ratio of polychromatic to normochromatic erythrocytes was determined individually for each animal by counting a total of 1000 erythrocytes.
Statistics:
The statistics of the test were riported in the study report.
The calculations were performed using the program MUTAI (SOP M/EDV/036) performed on a 386 AT DIGICOM. The program is written in PowerBASIC and is extensively tested.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

No signs of systemic intoxication were observed in female mice for the sigle oral doses of 1600, 800 and 400 mg/kg.
The highest
dose of 1600 mg/kg causes the death of 2 male mice within 24h. Conseguently the dose was lowered to 1200 mg/kg. The other doses of 800 and 400 mg/kg were tolerate without symptoms.

The results show no citotoxic effect of any chromosomal damages.


Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
No cytotoxic effect of the test substance were observed.
No potential of chromosomal damages were observed.
Executive summary:

This end point was assessed following the OECD 474 and it was performed in GLP conditions. Micronuclei arise as a result of damage to the chromosomes or the spindle apparatus through a mutagenic active substance during the mitotic cell division in proliferating bone marrow cells. The results show no increased incidence of micronucleated polychromatic erythrocytes

The calculated frequency of the micronuleated polychromatic erythrocytes of the groups treated with the substance was between 0,17 and 0,42 %.The observed frequency corresponds to the data reported in the literature which is related to the spontaneous rate of occurrence of micronuclei in polychromatic erythrocytes.

Hence a potential of chromosomal damages or damage to the mitotic apparatus could be excluded for the tested substance.