Cyclohexyldimethoxymethylsilane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04.10.1989 to 27.10.1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Cyclohexyldimethoxymethylsilane

EC Number:

402-140-1

EC Name:

Cyclohexyldimethoxymethylsilane

Cas Number:

17865-32-6

Molecular formula:

C9H20O2Si

IUPAC Name:

cyclohexyldimethoxymethylsilane

Test material form:

liquid

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 UK Ltd
- Age at study initiation: 6-8 weeks (on arrival at lab)
- Weight at study initiation: Approximately 200 g
- Fasting period before study: No
- Housing: Polypropylene cages
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: No data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-24
- Humidity (%): 35-65
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): No data

IN-LIFE DATES: From: 04.10.1989 To: 27.10.1989

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The whole body exposure chambers were of square section and were fitted with pyramidal tops. The chambers were made of perspex.
- Exposure chamber volume: 120 litres
- Method of holding animals in test chamber: Each chamber was divided by wire mesh partitions to provide 10 separate animal compartments.
- Source and rate of air: Described as 'clean, dried air', which was connected to the aerosol generator and the supply pressure was adjusted to give a flow rate of 25 litres/minute measured at the generator outlet tube.
- Method of conditioning air: The compressed air supply to the generator was dried, filtered and oil-free.
- System of generating aerosols: The generator was designed to produce and maintain an atmosphere containing a high proportion of respirable droplets. A flow rate of 0.5 ml/minute test substance to the atomiser was expected to give a concentration of aerosol just in excess of 5 mg/l of air.
- Method of particle size determination: Two samples were taken using a May multistage liquid impinger with acetone/methanol as the trapping agent in each stage (stage 1 - particles >5.5 micrometres; stage 2 - 5.5 to 2.0 micrometres; stage 3 - <2.0 micrometres). The contents of the stages were analysed to determine the particle size distribution in the atmosphere.
- Treatment of exhaust air: Each chamber was positioned inside a large glass walled cabinet equipped with an extractor fan exhausting to atmosphere through a collection filter.
- Temperature, humidity, pressure in air chamber: Approximately 23oC. No data for humidity or chamber pressure.

TEST ATMOSPHERE
- Brief description of analytical method used: Five air samples were taken from the chamber during each exposure and analysed to determine the concentration of test substance. The samples were drawn through an absorption trap, containing approximately 20ml of acetone, at a sampling rate of 2 litres/minute.
- Samples taken from breathing zone: no data

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: 81% in respirable range (<5.5 micrometres)

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5.53 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: Observed continuously during the exposure period for signs of toxicity, and twice daily during the observation period of 14 days. All rats were weighed daily.
- Necropsy of survivors performed: yes
- Other examinations performed: Food and water consumption was measured by cage. At the end of the observation period a detailed macroscopic examination was conducted. Lungs weights were measured. Lungs, liver and kidneys were examined microscopically.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.53 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: No deaths

Mortality:

No mortality occurred.

Clinical signs:

other: Partial closing of the eyes, hunched/prone posture, wet snout and slow breathing rate were observed, but are considered consistent with exposure to a mildly irritant aerosol. Wet fur, slow breathing rate, staggering and sensitivity to touch were observed,

Body weight:

There was an initial loss of weight or reduced bodyweight gain 1 -2 days after exposure. Subsequently, there was no difference between controls and treated animals.

Gross pathology:

Lung weights were normal. There were no abnormal macro- or micro-scopic findings.

Other findings:

Food consumption was reduced for 1 -2 days following exposure.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

In an acute aerosol inhalation study conducted using a protocol comparable to OECD Test Guideline 403 and in compliance with GLP (reliability score 1), the LC50 for cyclohexyldimethoxymethylsilane was greater than 5.53 mg/l in rats (whole-body). Wet fur, slow breathing rate, staggering and sensitivity to touch were observed, but only on the first day. All animals were normal by Day 1 of the observation period. There was an initial loss of weight or reduced bodyweight gain 1 -2 days after exposure. Subsequently, there was no difference between controls and treated animals. Food consumption was reduced for 1 -2 days following exposure. Lung weights were normal. There were no abnormal macro- or microscopic findings.