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Acute Toxicity: oral

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acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guidelineopen allclose all
according to guideline
OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)
according to guideline
EPA OPPTS 870.1100 (Acute Oral Toxicity)
GLP compliance:
yes (incl. QA statement)
Test type:
up-and-down procedure
Limit test:

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:

Test animals

Details on test animals or test system and environmental conditions:
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: Approximately 9-12 weeks old
- Weight at study initiation: Body weight variation did not exceed +/- 20% of the sex mean
- Fasting period before study: Food was withheld overnight (for a maximum of 20 hours) prior to dosing until 3-4 hours after administration of the
test substance.
- Housing: Individually housed in labeled Macrolon cages (Mill type, height 18 cm.) containing sterilized sawdust as bedding material (Litalabo , S.P.P.S., Argenteuil, France) and paper as cage-enrichment 9Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom).
- Diet (e.g. ad libitum): Free access to pelleted rodent diet (SM R/M-Z from SSNIFF(R) Spezialdiatem GmbH, Soest, Germany)
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: The acclimatization period was at least 5 days before the start of treatment under laboratory conditions. Accommodation was as described above except that the animals were group housed in labeled Macrolon cages (MIV type; height 18 cm)

- Temperature (°C): 21.0 +/- 3.0°C ( actual range: 19.5-21.6°C)
- Humidity (%): 30-70% (actual range: 31-81%)
- Air changes (per hr): 15 per hr
- Photoperiod (hrs dark / hrs light): 12 hrs dark/ 12 hrs light

Administration / exposure

Route of administration:
oral: gavage
unchanged (no vehicle)
Details on oral exposure:
The test substance was dosed undiluted as delivered by the sponsor.

2000 mg/kg (2.07 ml/kg) body weight
Frequency: Single dosage on Day 1
2000 mg/kg (2.07 mL/kg) body weight
550 mg/kg (0.569 mL/kg) body weight
175 mg/kg (0.181 mL/kg) body wieght
Dose volume calculated as dose level (g/kg)/ density (g/mL)
No. of animals per sex per dose:
Test substance was administered by oral gavage to a female Wistar rat at 2000 mg/kg body weight. In a stepwise procedure twelve additional females were dosed at 175, 550 or 2000 mg/kg body weight. The animals were dosed sequentially one at a time.
Control animals:
Details on study design:
- Frequency of observations and weighing: Observations: Twice daily. Weighing: Days 1 (pre-administration), 8 and 15.
- Necropsy of survivors performed: Yes
- Other examinations performed:
- Clinical Signs: At periodic intervals on the day of dosing (Day 1) and once daily thereafter, until Day 15. The symptoms were graded according to fixed scales and the time of onset, degree and duration were recorded: Maximum grade 3: grading slight (1) to severe (3). Maximum grade 1: presence is scored (1)
- Necropsy: The animals surviving to the end of the observation period were sacrificed by oxygen/carbondioxide procedure. All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities recorded.
- Organ Weights: The weight from the liver, kidneys and spleen were recorded from all animals that were necropsied after 21st of April 2008. These organs were also fixed in 10% buffered formalin (neutral phosphate buffered 4% formaldehyde solution) for posible further pathological investigations.
- Blood Sampling: As requested by sponsor, a blood sample was collected from aminal 13 (550 mg/kg) under iso-flurane 24 hrs post treatment. The sample was drawn from the retro-orbital sinus and collected into a tube prepared with EDTA for haematological parameters (0.5 mL)
The LD50 was estimated based on maximum likelihood by means of the AOT425StatPGM

Results and discussion

Effect levels
Key result
Dose descriptor:
Effect level:
ca. 1 234 mg/kg bw
Based on:
test mat.
2000 mg/kg bw; Number of animals: 7; Number of deaths: 5
550 mg/kg bw; Number of animals: 5; Number of deaths: 0
175 mg/kg bw; Number of animals: 1; Number of deaths: 0
Clinical signs:
Signs of toxicity related to dose levels: The decedents and moribund animal were found on the day of treatment (Day 1).
Clinical signs observed during the study period were as follows:
175 mg/kg: Hunched posture.
550 mg/kg: Lethargy, hunched posture, uncoordinated movements, flat posture, slow breathing, shallow respiration, piloerection, hypothermia.
2000 mg/kg: Lethargy, hunched posture, uncoordinated movements, flat posture, slow breathing, shallow and laboured respiration, piloerection, watery discharge eye, ptosis, salivation.
The surviving animals had recovered from the symptoms between Days 2 and 5.
Body weight:
The mean body weight gain shown by the surviving animals over the study period was considered to be similar to that expected of normal untreated
animals of the same age and strain.
Gross pathology:
Effects on organs: The weights of the liver and kidneys animal 13 (550 mg/kg) and the liver, kidneys and spleen of animals 14 (2000 mg/kg) were within the normal range. The weight of the spleen of animal 13 (550 mg/kg) was 0.306 and just below the normal range (0.40 - 0.69 grams). No abnormalities were found at macroscopic post mortem examination of the animals.
Other findings:
Haematology was perfomred on animal 13 (550 mg/Kg) and showed a slight increase in red blood cells, haemoglobin and haematocrit.

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
The Oral LD50 value of the test substance was estimated to be approximately 1234 mg/kg bw, within the range of 300-2000 mg/kg bw.
Executive summary:

An acute oral toxicity study was performed with OS1600 in the rat in accordance with OECD Guideline 425 using the Up and Down procedure. Test item was initially administered by oral gavage to a female rat at 2000 mg/kg bw. In a stepwise procedure 12 additional females were dosed at 175, 550 and 2000 mg/kg bw. The animals were dosed sequentially one at a time. All animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed on the day of death or after terminal sacrifice (Day 15). Animals at 2000 mg/kg bw were found dead. Clinical signes were observed at all doses, from hunched posture at 175 mg/ kg bw to lethargy, uncoordinated movements, slow breathing, shallow and laboured respiration, piloerection, discharge eye, ptosis and salivation at 2000 mg/kg bw. The surviving animals had recovered from this symptons. No effects were observed on the body weight gain. The liver and kidney weights of the two animals observed were within the historical data. Instead, the spleen weight was within the historical data in one of them and in the other one was lower. Slight increase in red blood cells, haemoglobi and haematocrit was observed in the analysed animal. No macroscopic abnormalities were observed. Based on these results, the LD50 of OS1600 in rats was determined to be ca. 1234 mg/kg bw and within the range of 300 -2000 mg/kg bw.