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Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
from 3 Sept to 17 Sept 1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report date:
1991

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Hoechst AG, SPF-Zucht, GERMANY
- Age at study initiation: 8-10 wk
- Weight at study initiation: males 188 (184-191) g; females 190 (185-200) g
- Housing: 1/plastic cage
- Diet: standard diet ad libitum
- Water: drinking water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 50 +/- 20
- Photoperiod (hrs dark / hrs light): 12h/ 12 h

IN-LIFE DATES: From: 1991-09-03 To: 1991-09-17

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
other: unchanged (no vehicle)
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
[from report in German]
- Exposure apparatus: cylindrical plastic cages housed in stainless steel inhalation chamber
- Exposure chamber volume: total volume 60 L
- Method of holding animals in test chamber: rats were fitted into test tubes with a coned end reaching into the test chamber
- Source and rate of air: 800 L/h
- Method of conditioning air: air was led at a constant pressure of 4 bar into a nozzle and through separators and filters
- System of generating particulates/aerosols: test substance was injected contineously into the air flow in the nozzle, primary aerosol built in a four-necked round-bottom flask, through a riser-pipe secondary arosol (smaller particle size) reached the test chamber
- Method of particle size determination: determination not possible

TEST ATMOSPHERE
- Brief description of analytical method used: gas chromatography with FID detector
- Samples taken from breathing zone: yes


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: not given
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): not given

Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
13.5 mg/L
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations 2/day; weights on Days 0, 7 and 14
- Necropsy of survivors performed: yes
- Other examinations performed: no other examinations
Statistics:
Single exposure concentration - no statistics presented.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 13 500 mg/m³ air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Mortality:
1/5 males; 0/5 females
Clinical signs:
other: Ataxia, irregular respiration, stupor, altered gait, prostration, tonic convulsions, trembling and reduced spontaneous activity were seen in both sexes during the 14-day observation period.
Body weight:
No treatment-related effect identified.
Gross pathology:
1/5 males had dark red, patchy lungs. [The extent of examination is unclear.]

Any other information on results incl. tables

Table 1: Concentration and mortality per animals treated

Analytical Conc. (mg/L)

Mortality (dead/total)

Males

Females

Combined

13.5

1/5

0/5

1/10

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In an acute inhalation (aerosol) study conducted in compliance with OECD 403 and GLP (reliability score 1) in which rats were exposed to triethoxy(methyl)silane for four hours to 13.5 mg/L only one animal from a total of ten died. The LC50 was said in the German report to be about 13.5 mg/L but would appear to be rather greater than this value.