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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:
key study
Study period:
Study completion date - 02 August 1976.
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1976
Report date:
1976

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
not specified
GLP compliance:
no
Test type:
acute toxic class method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium 3-[[3-methoxy-4-[(4-methoxyphenyl)azo]phenyl]azo]benzenesulphonate
EC Number:
264-129-6
EC Name:
Sodium 3-[[3-methoxy-4-[(4-methoxyphenyl)azo]phenyl]azo]benzenesulphonate
Cas Number:
63405-85-6
Molecular formula:
C20H18N4O5S.Na
IUPAC Name:
sodium 3-({3-methoxy-4-[(4-methoxyphenyl)diazenyl]phenyl}diazenyl)benzenesulfonate
Test material form:
other: Dust
Details on test material:
None
Specific details on test material used for the study:
Test Material: MA 23, D 956

Test animals

Species:
rat
Strain:
other: Charles River Rats
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Housing: Housed individually in stock cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum):ad libitum
- Acclimation period: 5 days

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
whole body
Vehicle:
air
Details on inhalation exposure:
Test animals were exposed in a specially constructed inhalation chamber. The chamber was designed so that the animals could be introduced into the test atmosphere after the desired dust concentration was established. Each animal was caged separately during exposure to minimize filtration of inspired air by animal fur. Dust was suspended with a specially designed dust feeder capable of producing high concentrations over a long period of time. The test material powder was passed through a high-velocity stream of clean, dry air (-40 °C dewpoint). The air-jet velocity was adjusted to obtain the desired concentration of suspended dust. The test atmosphere was then introduced into the exposure chamber at the top center, dispersed by a baffle plate and exhausted at the bottom of the chamber. Air flow rate through the system was measured with a rotameter connected in the air supply line upstream of dust contamination. The rotameter was calibrated with a wet-test meter after the exposure was completed.
Analytical verification of test atmosphere concentrations:
not specified
Duration of exposure:
4 h
Concentrations:
193.8, 850, 2850 mg/m³ air
No. of animals per sex per dose:
5 animals per group
Control animals:
yes
Details on study design:
Dust was suspended with a specially designed dust feeder capable of producing high concentrations over a long period of time. The test material powder was passed through a high-velocity stream of clean, dry air (-40 °C dewpoint). The air-jet velocity was adjusted to obtain the desired concentration of suspended dust. The test atmosphere was then introduced into the exposure chamber at the top center, dispersed by a baffle plate and exhausted at the bottom of the chamber. Air flow rate through the system was measured with a rotameter connected in the air supply line upstream of dust contamination. The rotameter was calibrated with a wet-test meter after the exposure was completed. The concentration of test material dust present in the exposure chamber was determined by sampling the test atmosphere in the breathing zone of the animals being exposed. The total weight of dust collected on a glass fiber filter was divided by the total volume of air drawn through the filter during the sampling period. Air flow rate for sampling was regulated by a calibrated Limiting orifice. The average analytical concentration of airborne dust was obtained by repeated air sampling. A sample of airborne dust was collected from the exposure chamber for the purpose of conducting a microscopic determination of particle size distribution. Particles were counted with respect to 4 size ranges, viz., 5 microns or smaller, 6 to 10 microns, 11 to 25 microns and larger than 25 microns. Particles less than 10 microns are generally considered to be respirable. The smallest particle which can be detected by the light-field technique employed is approximately 1µm. The largest particle observed was also recorded.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
873.1 mg/m³ air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
All deaths occurred between 8 and 18 hours after exposure.
Clinical signs:
other: The only reaction observed during the 3 exposures was hypoactivity.
Body weight:
Body weight gains for all surviving animals were within the normal limits.
Gross pathology:
No gross tissue changes attributable to the effects of the test material were observed in any of the rats that survived to completion of the study.

Any other information on results incl. tables

Result:


 




































Group No Total Number of Animals      Male/ FemaleNominal Concentration

Mortality


Male-Female



Weight Gain


Male-Female (grams)


 
15 /5193.8 mg/m³ air0/5 - 1/582.-48
25 /5850.0 mg/m³ air4/5 - 3/594-36
35 /52850.0 mg/m³ air3/5 - 4/567-31

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The LC50 of a 4 hour aerosol exposure for rats of both sexes is 873.1 mg/m³ air, when evaluated for a 14-day post treatment observation period.
Executive summary:

The acute inhalation toxicity test was performed with young adult rats. This study was conducted according to method similar or equivalent to OECD test guideline 403. 4 hour inhalation exposure was given to rats by specially constructed inhalation chamber of the animals. Body weight, clinical signs, mortality were monitored throughout an observation period of 14 days. The LC50 of a 4-hours aerosol exposure for rats of both sexes is 873.1 mg/m³ air, when evaluated for a 14 day post-treatment observation period.