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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
Type of information:
experimental study
Adequacy of study:
key study
Study period:
17/10/2006 - 11/12/2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
Version / remarks:
European Economic Community (EEC). Directive 2000/32/EC, Part B: Methods for the Determination of Toxicity; B.12: "Mutagenicity: In Vivo Mammalian Erythrocyte Micronucleus Test" (Published June 8, 2000)
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Version / remarks:
Organisation for Economic Co-operation and Development (OECD), OECD Guidelines for the Testing of Chemicals, Guideline No. 474: Mammalian Erythrocyte Micronucleus Test (adopted July 21, 1997)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Test material form:
solid: particulate/powder
Details on test material:
- Description: dark purple powder
- Solubility in the water: <= 0.412 g/L
- Melting point: > 250 °C
- Boiling point: > 250 °C
- Explosion: not explosion
- Log Pow: >= 3.3
- Test substance storage: at room temperature in the dark, 20°C, dry store
- Stability under storage conditions: stable
Specific details on test material used for the study:
SXjul2006 was suspended in corn oil (Roth, Karlsruhe, Germany). SXjul2006 concentrations were blended and treated with ultra-sonic waves to obtain a homogeneous suspension. SXjul2006 concentrations were dosed within 3 hours after preparation.

Test animals

Species:
mouse
Strain:
NMRI
Details on species / strain selection:
These mice are recommended by internation guidelines (e.g. OECD, EEC). Females were nulliparous and non-pregnant. The animals were provided by Charles River, Sulzfeld, Germany.
Sex:
male/female
Details on test animals and environmental conditions:
In the micronucleus main test 5 male and 5 female mice were treated per sampling time in each treatment group. Young adult animals were selected (6-8 weeks old).
The body weight of the mice at the start of the treatment were within 20% of the sex mean. The mice were identified by a unique number on the tail written with a marker pen. The animals were allocated to treatment groups as they came to hand from the delivery boxes.
On arrival and at the start of the treatment, all animals were clinically examined to ensure selected animals were in a good state of health.

Administration / exposure

Route of administration:
other: intraperitoneal injection
Vehicle:
Corn oil
Details on exposure:
Five male and five female animals were used in each of the six treatment groups, including negative and positive controls. All groups received a single intraperitoneal injection. The negative and positive control groups were treated with vehicle and 50 mg/kg body weight of cyclophosphamide (CP), respectively. Animals were dosed with SXjul2006 at 15 (two groups), 7.5 (one group) and 3.8 (one group) mg/kg body weight.
Duration of treatment / exposure:
Bone marrow of the groups treated with SXjul2006 was samples 24 or 48 (highest dose only) hours after dosing. Bone marrow of the negative and positive control groups was harvested 24 and 48 hours after dosing, respectively
Frequency of treatment:
All groups received a single intraperitoneal injection.
Doses / concentrationsopen allclose all
Dose / conc.:
15 other: mg/kg body weight
Remarks:
two groups
Dose / conc.:
7.5 other: mg/kg body weight
Remarks:
one group
Dose / conc.:
3.8 other: mg/kg body weight
Remarks:
one group
No. of animals per sex per dose:
five male and five female
Positive control(s):
The positive control used in the micronucleus test was cyclophosphamide (CP; CAS no. 50-18-0; Endoxan, Asta-Werke, Germany) dissolved in physiological saline (Ziekenhuis Apotheek Noordoost-Brabant, Den Bosch, The Netherlands) dosed as a single intraperitoneal injection of 50 mg/kg body weight.

Results and discussion

Applicant's summary and conclusion

Conclusions:
It is concluded that this test is valid and that SXjul2006 is not clastogenic in the micronucleus test under the experimental conditions described in this report.
Executive summary:

SXjul2006 induced a statistically significant increase in the mean number of micronucleated polychromatic erythrocytes compared to the corresponding solvent control group in female animal dosed with 7.5 mg/kg b.w. Since the mean number of micronucleated polychromatic erythrocytes per 2000 polychromatic erythrocytes (1.2 +- 1.1) of this group as well as the individual number of micronucleated polychromatic erythrocytes per 2000 polychromatic erythrocytes per animal were well within the historical data range (0 -4), the increase was considered not to be biologically relevant.

No increase in the frequency of micronucleated polychromatic erythrocytes, compared to the vehicle treated animals, was observed in the polychromatic erythrocytes of the bone marrow of all other dose groups treated with SXjul2006.

The incidence of micronucleated polychromatic erythrocytes in the bone marrow of all negative control animals was within the historical solvent control data range. Cyclophosphamide, the positive control substance, induced a statistically significant increase in the number of micronucleated polychromatic erythrocytes in both sexes. Hence, both criteria for an acceptable assay were met.

The groups that were treated with 7.5 and 3.8 mg SXjul2006/kg b.w. showed no decrease in the ratio of polychromatic to normochromatic erythrocytes compared to the vehicle controls, which reflects a lack of toxic effects of this compound on the erythropoiesis. In the group treated with 15 mg SXjul2006/kg b.w., sampled after 48 hours, a decrease in the ratio of polychromatic to normochromatic erythrocytes was observed compared to the vehicle controls. This provides evidence that SXjul2006 reaches the bone marrow and has a toxic effect on the erythropoiesis following a 48 h exposure. The animals treated with 15 mg SXjul2006/kg b.w. sampled after 24 hours did not show a decrease in the ratio of polychromatic to normochromatic erythrocytes compared to the vehicle controls.