Ethoxytrimethylsilane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-04-18 to 2018-02-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Version / remarks:

07 September 2009

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

August 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

OGYÉI National Institute of Pharmacy and Nutrition, Budapest, Hungary, Budapest, Hungary

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Ethoxytrimethylsilane

EC Number:

217-370-6

EC Name:

Ethoxytrimethylsilane

Cas Number:

1825-62-3

Molecular formula:

C5H14OSi

IUPAC Name:

ethoxytrimethylsilane

Test material form:

liquid

Test animals

Species:

rat

Strain:

other: CRL:WI

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sulzfeld, Germany
- Females nulliparous and non-pregnant: yes
- Age at study initiation: Group 1: 8 weeks old; Group 2: 9 weeks old
- Weight at study initiation: Group 1: 299-334 g (males) and 220-231 g (females); Group 2: 347-389 g (males) and 223-238 g (females)
- Housing: 3 animals by sex per cage
- Diet: ssniff SM R/M “Autoclavable Complete Feed for Rats and Mice – Breeding and Maintenance” provided ad libitum
- Water: tap water provided ad libitum
- Acclimation period: 6 days (Group 1), 12 days (Group 2)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17.7 – 26.4
- Humidity (%): 24 – 77
- Air changes (per hr): 15-20 air exchanges/hour
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: TSE Rodent Exposure System (TSE Systems GmbH, Bad Homburg, Germany)
- Method of holding animals in test chamber: Each rat was individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber. Only the nose of each animal was exposed to the test atmosphere.
- Source and rate of air: Fresh aerosol from the generation system was constantly supplied to the inner plenum (distribution chamber) of the exposure system from where, under positive pressure, it was distributed to the individual exposure ports. The flow of air through each port was at least 0.5 L/min.

TEST ATMOSPHERE
- Brief description of analytical method used: Vapour concentration was measured gravimetrically by adsorbent charcoal tube 17 times during each 4-hour exposure in both parts of the study.
- Samples taken from breathing zone: yes

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: The starting dose level, 10 mg/L was chosen by the Sponsor as the toxicity of the test item was unknown at 20 mg/L.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 4 h

Concentrations:

10.27 mg/L and 20.57 mg/L

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14-day observation period
- Frequency of observations and weighing: Clinical observations were performed on all animals during exposure at hourly intervals, following removal from restraint, approximately 1 hour after exposure, and daily for 14 days thereafter. Body weight was measured on Days 0 (before the exposure), 1, 3, 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: All animals were subject to a gross necropsy which included a detailed examination of the abdominal and thoracic cavities. Special attention was given to the respiratory tract for macroscopic signs of irritancy or local toxicity.

Statistics:

Not reported

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 20.57 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality occurred in Group 1 when exposed to a test atmosphere concentration of 10.27 mg/L for 4 hours and 1 out of the 6 animals died in Group 2 when exposed to a test atmosphere concentration of 20.57 mg/L for 4 hours.

Clinical signs:

other: Group 1: In the male animals, laboured respiration (slight to moderate), noisy respiration (slight), prostration/prone position, decreased activity (extreme) and incoordination (slight) were recorded on Day 0. These animals were symptom-free from Day 1. I

Body weight:

Slight body weight losses, noted in all animals of both Group 1 and Group 2 on Day 0-1, were considered to be related to the restraint and exposure procedures. No marked body weight loss was observed during the experiment in the surviving animals between Day 1-14. Body weights were within the range commonly recorded for this strain and age.

Gross pathology:

No test item-related macroscopic observations were noted at a dose level of 10.27 mg/L. There was no evidence of any changes in the rats dosed at 20.57 mg/L. No specific cause of death was determined for the animal, which was found dead on Day 2. Collapsed lungs were observed at necropsy and considered to be the agonal or post mortem change.

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008.

Conclusions:

In an acute inhalation toxicity study conducted according to OECD 436 and in compliance with GLP, the acute inhalation median lethal concentration (LC50) of ethoxy(trimethyl)silane in male and female Crl:WI rats was considered to be above 20.57 mg/L.