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Description of key information

In the key acute oral toxicity study, conducted according to OECD Test Guideline 423 and in compliance with GLP, the LD50 for triethoxy(2,4,4-trimethylpentyl)silane was concluded to be > 2000 mg/kg bw. No deaths occurred up to the highest dose tested (Research and Consulting Company Ltd., 1998).

In the key acute dermal toxicity study, conducted according to OECD Test Guideline 402 and in compliance with GLP, the LD50 for triethoxy(2,4,4-trimethylpentyl)silane was concluded to be > 2000 mg/kg bw (BSL Bioservice, 2001a).

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records
Reference
Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 Days
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
acute toxic class method
Limit test:
yes
Species:
rat
Strain:
other: HanIbm: WIST (SPF)
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Biological Research Laboratories.
- Age at study initiation: 8-10 weeks
- Weight at study initiation: Males: 206-216 g. Females: 171-190 g.
- Fasting period before study: Yes, overnight.
- Housing: Groups of three in Makrolon type-4 cages.
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: One week


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22± 3
- Humidity (%): 40-66
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 0.2 g/ml
- Justification for choice of vehicle: None given


MAXIMUM DOSE VOLUME APPLIED: 10 ml/kg bw


CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: None given.
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
Three
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Mortality and clinical signs: four times per day on the day of treatment, and once daily thereafter. Body weights: Pre-administration and on Days 8 and 15.
- Necropsy of survivors performed: yes, on day 15 after observations.
- Other examinations performed: Macroscopic examination.
Statistics:
No statistical analysis as no deaths occurred.
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 occurred.
Mortality:
No deaths occurred.
Clinical signs:
There were no clinical signs.
Body weight:
The body weights were in the expected range.
Gross pathology:
No abnormal findings.
Other findings:
No other findings.
Interpretation of results:
GHS criteria not met
Conclusions:
In the acute oral toxicity study, conducted according to OECD Test Guideline 423 and in compliance with GLP, the LD50 for triethoxy(2,4,4-trimethylpentyl)silane was concluded to be >2000 mg/kg bw. No deaths occurred up to the highest dose tested.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Link to relevant study records
Reference
Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Harlan Winkelmann GmbH
- Age at study initiation: No data
- Weight at study initiation: 200-300 g
- Fasting period before study: Not stated.
- Housing: Individually in Macrolon cages.
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 'Adequate'. Period not stated.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22± 3
- Humidity (%): 55 ±10
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:
semiocclusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
TEST SITE
- Area of exposure: Not stated
- % coverage: At least 10% of total body surface
- Type of wrap if used: Semi-occlusive gauze dressing and non-irritating tape, with a bandage that wrapped around the abdomen.


REMOVAL OF TEST SUBSTANCE
- Washing (if done): Yes, with water
- Time after start of exposure: 24 hours.


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): No data
- Constant volume or concentration used: no data



Duration of exposure:
24 hours
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
Five
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Animals were weighed prior to application of test substance and on Day 7 and 15. Cageside observations were made several times per day on the day of application and once per day thereafter.
- Necropsy of survivors performed: yes
- Other examinations performed: Macroscopic examination following necropsy.
Statistics:
No statistics were performed.
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
There were no deaths.
Clinical signs:
No clinical signs were observed.
Body weight:
Weight gain of the male animals was within the expected range. The female animals lost weight within the first week after application, but had a normal weight gain during the second week. This was probably due to the stress of the manipulation procedure, which means a big physical strain for the animals. This was more visible for the female animals because they had already reached their adult weights at the beginning of the study.
Gross pathology:
There were no findings.
Other findings:
No other findings were reported.
Interpretation of results:
GHS criteria not met
Conclusions:
In the acute dermal toxicity study, conducted according to OECD Test Guideline 402 and in compliance with GLP, the LD50 for triethoxy(2,4,4-trimethylpentyl)silane was concluded to be > 2000 mg/kg bw.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw

Additional information

There are key acute oral and dermal toxicity studies available for the registered substance, triethoxy(2,4,4-trimethylpentyl)silane.

No acute inhalation data are available for the registration substance. Therefore, data are read-across as supporting from the structural analogue substance trimethoxy(2,4,4-trimethylpentyl)silane.

In the key acute oral toxicity study, conducted according to OECD Test Guideline 423 and in compliance with GLP, two groups, each with three male or three female HanIbm: WIST (SPF) rats, were given a single oral (gavage) administration of triethoxy(2,4,4-trimethylpentyl)silane at 2000 mg/kg bw in corn oil. The test substance was diluted in corn oil at a concentration of 0.2 g/ml and administered at a volume of 10 ml/kg. The animals were examined for clinical signs four times during study day 1 and once daily during study days 2 to 15. Mortality/viability was recorded together with clinical signs at the same time intervals. Body weights were recorded on day 1 prior to administration and on days 8 and 15. All animals were necropsied and examined macroscopically. No deaths occurred during the study, and there were no clinical signs, effects on body weight, or abnormal macroscopic findings. The LD50 for triethoxy(2,4,4-trimethylpentyl)silane was concluded to be > 2000 mg/kg bw (Research and Consulting Company Ltd., 1998).

In the key acute dermal toxicity study, conducted according to OECD Test Guideline 402 and in compliance with GLP, triethoxy(2,4,4-trimethylpentyl)silane was applied undiluted onto the skin of Wistar rats (five/sex) under a semi-occlusive dressing for 24 hours at a dose of 2000 mg/kg bw. After 24 hours the skin was washed with water to remove any excess test substance. The animals were then observed daily for 14 days. Body weights were measured on the day before treatment (day 1) and on days 7 and 15. On day 15 the animals were sacrificed and a macroscopic examination was conducted. There were no deaths, clinical signs of toxicity or abnormal findings at necropsy. Weight gain of the male animals was within the expected range. The female animals lost weight within the first week after application, but had a normal weight gain during the second week. This effect was considered due to the stress of the manipulation procedure, which means a big physical strain for the animals and it was more visible for the female animals because they had already reached their adult weights at the beginning of the study. The LD50 for triethoxy(2,4,4-trimethylpentyl)silane was concluded to be > 2000 mg/kg bw (BSL Bioservice, 2001a).

A supporting inhalation study is read-across from trimethoxy(2,4,4-trimethylpentyl)silane. In a good quality study (Hoechst, 1986a) exposure of Wistar rats to an aerosol of trimethoxy(2,4,4-trimethylpentyl)silane at a concentration of 11.2 mg/l air did not cause any deaths. Therefore the LC50 was concluded to be greater than 11.2 mg/l.

Justification for classification or non-classification

Based on the available acute oral and dermal toxicity studies, triethoxy (2,4,4-trimethylpentyl)silane is not classified for acute toxicity according to Regulation (EC) No 1272/2008.