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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:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Study period:
1994
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
yes
Remarks:
, but the observed deviation was not considered to have compromised the validity or integrity of the study.
Qualifier:
according to
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
Deviations:
yes
Remarks:
, but the observed deviation was not considered to have compromised the validity or integrity of the study.
Qualifier:
according to
Guideline:
EPA OTS 798.5395 (In Vivo Mammalian Cytogenics Tests: Erythrocyte Micronucleus Assay)
Deviations:
yes
Remarks:
, but the observed deviation was not considered to have compromised the validity or integrity of the study.
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
semi-solid (amorphous): gel
Remarks:
migrated information: paste
Details on test material:
- Name of test material (as cited in study report): P.I.A.S.
- Physical state: brown thisk paste
- Purity: assumed to be 100 % for dose calculation
- Lot/batch No.: B359
- Expiration date of the lot/batch: December 1994
- Storage condition of test material: at refrigerator temperature

Test animals

Species:
mouse
Strain:
other: OF1 (IOPS Caw)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: IFFA-CREDO, 69592 L'Arbresle, France
- Age at study initiation: 6 weeks
- Weight at study initiation (main study): 27.2 to 30.8 g for males, 22.5 to 26.9 g for females
- Assigned to test groups randomly: yes
- Housing: animals are housed in groups of 3 animals (preliminary study) or 5 animals (main study) in translucent polypropylene or polycarbonate cages (205 * 118 * 127 mm)
- Diet (e.g. ad libitum): pelleted complete diet ad libitum
- Water (e.g. ad libitum): filtered (0.2µm) mains drinking water ad libitum
- Acclimation period: 3 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/- 3°C
- Humidity (%): 50 to 20 %
- Air changes (per hr): minimum 8 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours light (artificial) / 12 hours dark

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: corn oil
- Justification for choice of solvent/vehicle: corn oil was used for 26 week oral (gavage) toxicity study in the rat.
- Lot/batch no. (if required): A 25127 90043
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Dosing suspensions were performed by using corn oil to obtain the following concentrations:
- preliminary study:
* dose volume: 10 mL/kg b.w.
* concentration of dosing preparation: 500.0, 325.0, 211.3, 137.3, 89.2 mg/mL
* dose administrated: 5000, 3250, 2113, 1373, 892 mg/kg b.w.

- main study:
* dose volume: 10 mL/kg b.w.
* concentration of dosing preparation: 500.0 mg/mL
* dose administrated: 5000 mg/kg b.w.
Frequency of treatment:
Once, by gavage
Post exposure period:
Animals were killed 24, 48 or 72 hours after the administration of the test article.
No. of animals per sex per dose:
- preliminary study: 15 males and 15 females (with 3 males and 3 females per treated group)
- main study: 35 males and 35 females (with 5 males and 5 females per treated group)
Control animals:
yes, concurrent vehicle
Positive control(s):
- Positive control: cyclophosphamide
- Route of administration: intraperitoneal route
- Doses / concentrations: 100 mg/kg b.w. (dose volume: 10 mL/kg b.w.)

Examinations

Tissues and cell types examined:
- tissues: bone marrow of femurs from each animal
- cell types examined: erythrocytes
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION:
An initial dose range finding study is performed with the test article at suitable dose levels (5000, 3250, 2113, 1373, 892 mg/kg b.w.)

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):
The main study is performed with the test article at the dose concentration of 5000 mg/kg b.w.. A single administration is perfomed by oral route, and animals are sacrified 24, 48 or 72 hours after the treatment.

DETAILS OF SLIDE PREPARATION:
The animals are first treated, and then sacrificed ; the femurs are removed and the bone marrow extracted in foetal calf serum.
The homogenized centrifugate is spread on slides and stained (May Grünwald-Giemsa technique).


Evaluation criteria:
- Study: slides are scored and decoded to determine the ratio of PCE/NCE and the frequency of micronucleated PCE/1000 PCE. A mean and a standard deviation are calculated for each group.
- Control: the PCE/NCE ratios and frequencies of micronucleated PCE in vehicle control animals are compared with historical control ranges to determine whether or not the assay is acceptable.

PCE = polychromatic erythrocytes
NCE = normochromatic erythrocytes
Statistics:
Student's t test

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
Additional information on results:
RESULTS OF RANGE-FINDING STUDY
- Dose range: 5000, 3250, 2113, 1373 and 892 mg/kg b.w.
- Clinical signs of toxicity/mortality, in test animals: no clinical signs and no mortality were observed over 3 days after dosing any group.

RESULTS OF DEFINITIVE STUDY
- Dose: 5000 mg/kg b.w.
- Clinical signs/mortality: no clinical signs and no mortality were observed over 3 days after dosing any group.

- Induction of micronuclei (for Micronucleus assay):
* Positive control: it induced a clear and statistically significant increase in the number of micronucleated NCE: the group mean for both sexes combined (46.5/1000) was approximately 29 times the mean in the concurrent negative control.
* Negative control: the incidence of micronucleated PCE in the vehicle control groups was within the range anticipated in this type of study at testing facility.
* Treated groups: no statistically significant increase in the number of micronucleated PCE was observed in any of the treated groups, compared to the concurrent negative control group.

- Ratio of PCE/NCE (for Micronucleus assay):
* Positive control: a statistically significant decrease (p < 0.05) in the number of PCE was noted.
* Negative control: PCE/NCE ratios were within the range anticipated in this type of study at testing facility.
* Treated group: a statistically significant decrease (p < 0.05) in the number of PCE was noted in the treated group sacrified 48 hours after dosing when compared to the values of the negative control group at the same kill time.
No cytotoxicity was noted in the treated group sacrified 24 and 72 hours after dosing.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Under the experimental conditions, the test article P.I.A.S (Batch B359), did not induce micronuclei in the polychromatic erythrocytes of the bone marrow of mice treated at 5000 mg/kg b.w.. Although this dose level did not cause mortality and did not induce any clinical signs, it did however induce a statistically significant decrease in the number of PCE in the treated group killed 48 hours after dosing.
In conclusion, P.I.A.S. induced no genotoxic activity under these experimental conditions.
Executive summary:

The mutagenic potential of the test article P.I.A.S. was evaluated by means of the micronucleus test in mice. The product was administered orally at the dose level of 5000 mg/kg b.w. to groups of 10 mice (5 males and 5 females), sacrificed 24, 48 and 72 hours post-dose. Negative (corn oil) and positive control (cyclophosphamide) were included in this study.

The frequency of micronuclei and the ratio poly/normochromatic erythrocytes were calculated for each animal and for each group.

Under the experimental conditions, the test article P.I.A.S. (Batch B359), did not reveal any mutagenic activity on 1000 polychromatic erythrocytes per mice treated at 5000 mg/kg b.w. compared with a positive control group.

Although this dose level did not cause mortality and did not induce any clinical signs, only a decrease in the number of polychromatic erythrocytes was observed in the animals examined 48 hours after administration.

In conclusion, P.I.A.S. induced no genotoxic activity under these experimental conditions.