Trimethoxy(2-methylpropyl)silane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30.11.1983 to 14.12.1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate OECD test guideline, with acceptable restrictions. The restrictions were lack of some protocol and results detail. No information on test substance purity.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

no analytical verification of concentration, parts of protocol and results missing from report.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Trimethoxy(2-methylpropyl)silane

EC Number:

242-272-5

EC Name:

Trimethoxy(2-methylpropyl)silane

Cas Number:

18395-30-7

Molecular formula:

C7H18O3Si

IUPAC Name:

trimethoxy(2-methylpropyl)silane

Details on test material:

- Name of test material (as cited in study report): Dow Corning X1-2204 (isobutyltrimethoxysilane)
- Substance type: Alkoxysilane
- Physical state: Liquid
- Analytical purity: No data
- Purity test date: No data
- Lot/batch No.: BNO93006
- Expiration date of the lot/batch: No data
- Stability under test conditions: No data
- Storage condition of test material: No data

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratory
- Age at study initiation: No data
- Weight at study initiation: 210 ±35 g
- Fasting period before study: No
- Housing: Stainless steel cages (cages designed to permenantly house the animals during exposure and observation period.
- Diet (e.g. ad libitum): Ad libitum (except during actual exposure)
- Water (e.g. ad libitum): Ad libitum (except during actual exposure)
- Acclimation period: Seven days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ±2
- Humidity (%): 30-70
- Air changes (per hr): 12-15
- Photoperiod (hrs dark / hrs light): No data

IN-LIFE DATES: From: 30.11.1983 to 14.12.1983

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 450 litre stainless steel and glass exposure chambers under dynamic conditions.
- Method of holding animals in test chamber: cage only
- Source and rate of air: The chamber air was supplied by a heating, ventilation and air conditioning (HVAC) system that was separate from the general laboratory system. The intake air was filtered (HEPA and charcoal), and temperature and humidity were controlled.
- Treatment of exhaust air: No data
- Temperature, humidity, pressure in air chamber: 22 ±2oC, 30-70%, no pressure information.

TEST ATMOSPHERE
- Brief description of analytical method used: No details in report.
- Samples taken from breathing zone: No data

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 4 h

Concentrations:

1525 ppm (Based on rangefinding study) (report states that this is approximately 11 mg/l)

No. of animals per sex per dose:

Five

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Animals were weighed on days 7 and 14 of the observation period. They were observed frequently during the exposure period and daily during the week days of the observation period.
- Necropsy of survivors performed: yes, a complete gross pathological examination was performed on all major tissues and organs. Special attention was paid to the lungs and trachea.

Statistics:

None

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1 525 ppm

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: Equivalent to 11 mg/l. There were no deaths within the 14 days post-exposure.

Mortality:

There were no deaths.

Clinical signs:

other: The experimental animals appeared lethargic and unresponsive during the exposure period. However, on removal from the chamber, the animals quickly recovered and did not show any stress or signs of toxicity during the 14-day observation period. The control

Body weight:

There were no effects on body weights in control and test animals.

Gross pathology:

No exposure-related gross pathological alterations were observed in any of the organs or tissues.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In an acute inhalation study (that was comparable to OECD 403 and to GLP (reliability score 2), the LC50 for Dow Corning X1-2204 (isobutyltrimethoxysilane) was greater than 1525 ppm (11 mg/l) (the only concentration tested) in Sprague-Dawley rats. The animals were lethargic and unresponsive during the exposure period. However, on removal from the chamber, the animals quickly recovered and did not show any stress or signs of toxicity during the 14-day observation period.