Registration Dossier

Administrative data

Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2000-03-16 to 2000-03-30
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid

Test animals

Species:
rabbit
Strain:
New Zealand White
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: No data
- Age at study initiation: 12 weeks old
- Weight at study initiation: 2308 - 2580 g
- Housing: the rabbits were housed individually in suspended metal cages.
- Diet: standard laboratory diet, SDS Stanrab (P) SQC rabbit diet, ad libitum. Autoclaved hay was supplied three times a week.
- Water: drinking water, ad libitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 to 24.5°C
- Humidity (%): 20-38 %
- Air changes (per hr): 15/hour
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Type of coverage:
semiocclusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
TEST SITE
- Area of exposure: dorso-lumbar region
- % coverage: 10 %
- Type of wrap if used: The treatment area was covered with porous gauze held with non-irritating dressing and further covered by waterproof dressing.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes. The area was wiped with a towel moistened with water to remove any residual test substance.
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 1.87 ml/kg
- Constant volume or concentration used: yes


Duration of exposure:
24 hours
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
5 males and 5 females
Control animals:
not required
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All animals were observed twice daily for mortality. Individual weights were recorded on days 1, 8 and 15.
- Necropsy of survivors performed: yes
- Other examinations performed: Animals were observed for clinical signs at 30 min and then approximately every hour on day 1, thereafter twice a day (morning and evening) until the end of the study period. The treated area of each animal was examined daily for erythema, eschar formation and oedema.
Statistics:
Group mean body weights and body weight changes were calculated using appropriate means.

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Remarks on result:
other: No deaths observed
Mortality:
No mortality occurred during the 14-day study period.
Clinical signs:
No clinical signs of toxicity were observed in any of the test animals.
Body weight:
Weight loss was evident in 2 females on day 8, and in another female on days 8 and 15. The expected body weight gain was observed in the majority of the animals.
Gross pathology:
Gaseous distension in the large intestine was noted in one female at necropsy. No macroscopic abnormalities were observed in the rest of the animals.
Other findings:
There were no dermal reactions observed throughout the study.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In an acute dermal toxicity study, the reported LD50 value for 1,3,3,5-tetramethyl-1,1,5,5-tetraphenyltrisiloxane was >2000 mg/kg bw in rabbits.