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Diss Factsheets

Administrative data

acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 21 - August 19, 2010
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to current OECD test guidelines and GLP principles.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
GLP compliance:
Test type:
acute toxic class method
Limit test:

Test material

Constituent 1
Details on test material:
- Name of test material (as cited in study report): E-BK105
- Physical state: Black powder, solid
- Lot/batch No.: MB-1
- Expiration date of the lot/batch: July 6, 2015
- Storage condition of test material: Room temperature, dark place

Test animals

other: Crl:CD(SD)
Details on test animals or test system and environmental conditions:
- Source: Charles River Laboratories Japan, Inc. (Hino breeding center)
- Age at study initiation: 9 weeks
- Weight at study initiation: 187.9-210.5 g
- Fasting period before study: From the evening on the day before the administration (approx 18 hours predose) to about 3 hours postdose.
- Housing: Stainless steel cages (W226xD346xH198 mm), stainless steel racks and feeders, one animal per cage
- Diet (ad libitum): Pellet diet (CRF-1, Oriental Yeast Co., Ltd.) (each lot analysed: contaminants confirmed to be within acceptable limits of the test facility)
- Water (ad libitum): Well water admixed with NaClO (about 2 ppm) (analysed every 6 months: contaminants confirmed to be in compliance with the waterworks law of Japan)
- Acclimation period: 6 days for experiment 1 and 8 days for experiment 2

- Temperature (°C): 23.6-24.6
- Humidity (%): 44.9-61.3
- Air changes (per hr): 10 to 20
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Details on oral exposure:
- Concentration in vehicle: test substance solved to make a dosing solution at a concentration of 100 mg/ml


DOSAGE PREPARATION (if unusual): The dosing volumes for individual animals were calculated on the basis of the body weight measured just before administration.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: The lethal dose of a similar substance was reported to be 2000 mg/kg or above. Therefore, the dose level for the first administration was set at 2000 mg/kg, which is the maximum dose recommended in the guideline applied to this study. As a result, as no death or moribundity was observed on the day after the first administration the dose level for the second administration was also set at 2000 mg/kg.
2000 mg/kg bw
No. of animals per sex per dose:
3 females in each of 2 experiments
Control animals:
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Mortality and clinical signs were observed before the dosing (Day 1, day of initial administration), 30 min, 1, 3, and 5 hours postdose on Day 1 and once daily for 14 days thereafter. Body weight was measured just before the administration (Day 1) and on Days 4, 8, and 15.
- Necropsy of survivors performed: yes
- Other examinations performed: none
not applicable

Results and discussion

Effect levels
Dose descriptor:
Effect level:
>= 2 000 mg/kg bw
Based on:
test mat.
No deaths were noted in any animal in experiment 1 and 2.
Clinical signs:
other: Test substance mixed feces was observed in all animals from 0.5 or 1 hours on Day 1 (administration day) to Day 3 or 4, and chromaturia (blackish) was observed in all animals from Day 2 to Day 4 or 5 in experiment 1 and 2. These changes were attributed to
Gross pathology:
No abnormalities were noted in any animal in experiment 1 or 2.

Applicant's summary and conclusion

Interpretation of results:
not classified
Migrated information Criteria used for interpretation of results: EU
The LD50 of E-BK105 in rats was determined to be above 2000 mg/kg bw under the conditions of this study (OECD 423).
Executive summary:

A single oral administration of E-BK105 (dissolved in water) by gavage was conducted to female Crl:CD(SD) rats aged 9 weeks to evaluate its acute oral toxicity in accordance with the OECD test guideline 423. A dose of 2000 mg/kg bw was employed for the first and second administration to each three rats. As a result, there was no mortality, body weight gain effects, or necropsy findings. Clinical signs were restricted to test substance mixed feces and chromaturia (blackish). In conclusion, the LD50 of E-BK105 in rats is determined to be above 2000 mg/kg bw under the conditions of this study.