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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:
experimental study
Adequacy of study:
key study
Study period:
1987-04-06, 1987-09-03
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report Date:
1987

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
not specified
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: Solid
- Analytical purity: Lab. sample
- Lot/batch No.: WR 629
- Expiration date of the lot/batch: 1990-02
- Stability under test conditions: Stable

Test animals

Species:
hamster, Chinese
Strain:
not specified
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: CIBA-GEIGY Tierfarm, Sisseln, Switzerland
- Age at study initiation: Females 6 - 10 weeks; males 4 - 9 weeks
- Weight at study initiation: Females 23-32 g; males 26-35 g
- Assigned to test groups randomly: yes
- Diet: Ad libitum, standard diet: NAFAG No.924
- Water: Ad libitum
- Acclimation period: 4 - 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21
- Humidity (%): 51 - 74
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle used: Carboxymethylcellulose (CMC) 0.5 % in water
- Justification for choice of solvent/vehicle: TK 11319 is insoluble in water
- Concentration of test material in vehicle: 5000 mg/kg bw in 20 mL/kg bw
Duration of treatment / exposure:
Single dose exposure
Frequency of treatment:
Single dose
Post exposure period:
16, 24, and 48 hours
Doses / concentrations
Dose / conc.:
5 000 mg/kg bw/day (actual dose received)
Remarks:
In a preliminary toxicity test the dose of 5000 mg/kg was determined as the highest applicable in the mutagenicity assay.
No. of animals per sex per dose:
8 per sex per group
Control animals:
yes, concurrent no treatment
Positive control(s):
A dose of 64 mg/kg bw of cyclophosphamide was used as positive control. The route of administration was oral per gavage.

Examinations

Tissues and cell types examined:
Bone marrow was harvested from the shafts of both femurs with fetal calf serum. After centrifugation small drops of the sediment mixture were transferred on the end of a slide, spread out with the aid of a polished cover glass. The preparations were air-dried. Within 24 hours, the slides were stained in undiluted May-Grünwald solution for 3 min then in May-Grünwald solution/water (1/1) for 2 min. After being rinsed in distilled water, the slides were left immersed in diluted Giemsa solution (16.6 %) for 10 min. After rinsing with distilled water and air-drying, the slides were cleared in xylene and mounted. 1000 polychromatic erythrocytes (PCE) per animal were used to determine the incidence of micronucleated PCE. A total of 1000 erythrocytes were counted for determination of the ratio of polychromatic to normochromatic erythrocytes (PCE/NCE -ratio).

Statistics:
The significance of difference is assessed by χ2-test.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Remarks:
No significant differences in the PCE/NCE-ratio between treated groups and controls.
Vehicle controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

Table 1. Effect of test article on bone marrow cells of chinese hamster: arithmetic mean per sex and group.


Sacrifice (h) 

16 24 48

Control TK 11319 Control TK 11319 Control TK 11319
sex of the animals
polychromatic erythrocytes (P) 626 520 550 551 489 471 482 486 555 539 459 485
normochromatic erythrocytes (N) 374 480 450 449 511 529 518 514 445 461 541 515
ratio P/N 1.7 1.1 1.2 1.2 1.0 0.9 0.9 0.9 1.2 1.2 0.8 0.9
P with micronuclei 0.2 0.2 0.4 0.2 0.6 1.0 1.0 0.6 0.8 0.8 0.6 0.6
percent of P with micronuclei 0.02 0.02 0.04 0.02 0.06 0.10 0.10 0.06 0.08 0.08 0.06 0.06

Table 1 (cont.). Effect of test article on bone marrow cells of chinese hamster: arithmetic mean per sex and group (positive control).


Sacrifice (h)

24

Control Cyclophosphamide (64 mg/kg)
sex of the animals
polychromatic erythrocytes (P) 489 471 452 450
normochromatic erythrocytes (N) 511 529 548 550
ratio P/N 1.0 0.9 0.8 0.8
P with micronuclei 0.6 1.0 27.0 32.2
percent of P with micronuclei 0.06 0.10 2.70 3.22

Applicant's summary and conclusion

Conclusions:
The substance tested in the in vivo Micronucleus Test with Chinese Hamster (method similar to OECD 474) up to 5000 mg/kg bw was not genotoxic.
Executive summary:

In this guideline (OECD 474) study conducted to GLP standards, the test material (EC 404-360-3) was tested in vivo on chinese hamsters (male and female) aged 4 -10 weeks. The test substance was administered via oral gavage in a vehicle of 0.5% carboxymethylcellulose (concentration of test material in vehicle was 5000 mg/kg bw in 20 ml/kg bw). 8 animals of each sex per dose were tested, with various sacrifice times (16, 24 and 48 hours). After sacrifice, bone marrow was harvested from the shafts of both femurs with fetal calf serum for analysis. As well as a control, there was a positive control using 64 mg/kg bw of cyclophosphamide (also administered via oral gavage). The bone marrow tissue was then examined for incidence of polychromatic erythrocytes (PCE) - an increase in frequency being an indicator of induced chromosome damage. No PCE was observed for the test material, therefore EC 404 -360 -3 is not genotoxic.