Registration Dossier

Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1969
Report Date:
1969

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Principles of method if other than guideline:
Internal BASF method was used which was in large part equivalent to OECD guideline 401
GLP compliance:
no
Remarks:
pre-dates GLP
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
- Name of test material (as cited in study report): trimethylhydroquinone

Test animals

Species:
rat
Strain:
not specified
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: mean 228 g (male), 188 g (female)

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: aqueous suspension with tragacanth
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 2, 16, 30%
Doses:
200, 1600, 2500, 3200, 4000, 5000, 6400 mg/kg bw
No. of animals per sex per dose:
10
Control animals:
no
Details on study design:
- Duration of observation period following administration: 7 days
- Frequency of observations and weighing: prior to study
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
ca. 3 200 mg/kg bw
Mortality:
6400 mg/kg bw: 10/10 males within 24 h; 10/10 females within 24 h
5000 mg/kg bw: 5/10 males within 24 h; 8/10 males within 7 days; 8/10 females within 24 h; 9/10 females within 7 days
4000 mg/kg bw: 3/10 males within 24 h; 4/10 males within 48 h; 7/10 females within 24 h; 8/10 females within 48 h
3200 mg/kg bw: 3/10 males within 24 h; 4/10 females within 24 h; 7/10 females within 48 h; 8/10 females within 7 d
2500 mg/kg bw: 3/10 males within 24 h; 3/10 females within 24 h
1600 mg/kg bw: 2/10 males within 24 h; 3/10 males within 48 h; 2/10 females within 24 h
200 mg/kg bw: no mortalities
Clinical signs:
Clinical symptoms:
Dyspnea and prone position were the major clinical symptoms observed.
2500 - 6400 mg/kg bw: No clinical symptoms were noted immediately after dosing. At one hour after dosing, prone position, intermittent respiration, cyanosis, apathy, and dyspnea was observed. During the following two days, squatting posture, accelerated respiration, piloerection, and partially stuck eyes was observed. In these five groups, totally 66/100 animals died. In survivors, slight improvement of the clinical symptoms was noted by 4-5 days; all survivors were normal by 6-7 days.
1600 mg/kg bw: No clinical symptoms were noted on the day of dosing. Squatting posture, eyelid closure, and piloerection was observed on day 1 after dosing. Totally, 5/20 animals died; surviving animals were normal by 2 days after dosing.
200 mg/kg bw: No clinical signs of toxicity were noted.
Gross pathology:
In decedents, serous skin/mucosa with accumulation of fluid (6 rats), hydrothorax (6 rats), venous congerstion (3 rats), serous adhesion at the snout (1 rat), congestion of the liver (1 rat), chronic-inflammatory brochitis (1 rat), and bronchiectasis was observed. In surviors sacrificed after the 7-day observation, hydrothorax (2 rats) and chronic bronchitis (3 rats) was observed.

Applicant's summary and conclusion

Interpretation of results:
other: not classified acc. to CLP-regulation
Conclusions:
The present data on acute oral toxicity do not fulfill the criteria laid down in CLP-regulation and therefore the test substance trimethylhydroquinone is not classified.
Executive summary:

In an assay similar to OECD TG 401 on the acute oral toxicity of trimethylhydroquinone the following value for the LD50 was determined to be 3200 mg/kg bw.