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Diss Factsheets

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1976
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

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)
Principles of method if other than guideline:
Inhalation toxicity was tested according to the method of Sachsse et al. (1973): Measurement of inhalation toxicity of aerosols in small laboratory animals. In: Proceedings of the Europ. Soc. for the Study of Drug Toxicity, Vol. XV, pp. 239-251, Zurich, June 1973.
GLP compliance:
no
Remarks:
prior to GLP

Test material

Constituent 1
Chemical structure
Reference substance name:
2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole)
EC Number:
230-426-4
EC Name:
2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole)
Cas Number:
7128-64-5
Molecular formula:
C26H26N2O2S
IUPAC Name:
5-tert-butyl-2-[5-(5-tert-butyl-1,3-benzoxazol-2-yl)thiophen-2-yl]-1,3-benzoxazole

Test animals

Species:
rat
Strain:
other: Tif: RAIf (SPF) strain
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: in-house
- Weight at study initiation: 190 - 195 grams
- Housing: Macrolon cages, type 4 (9 animals to a cage)
- Diet: rat food - NAFAG, Gossau SG; ad libitum
- Water: ad libitum
- Acclimation period: 4 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 1
- Humidity (%): 55 +/- 5
- Photoperiod (hrs dark / hrs light): 10/14

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose/head only
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: "Grafix Exaktomat Injector"
- Method of holding animals in test chamber: PVC tubes
- System of generating particulates/aerosols: nozzle under a pressure of 2 atm at a rate of 20 L/min
- Method of particle size determination: Cascade Impactor with selectron filters
- Relative humidity: 32%

TEST ATMOSPHERE
- Brief description of analytical method used: gravimetry
- Samples taken from breathing zone: yes

VEHICLE
- Composition of vehicle: air

TEST ATMOSPHERE
- Particle size distribution:
> 7 µm: ca. 56%
3-7 µm: ca. 15%
1-3 µm: ca. 11%
< 1µm: ca. 18%
Analytical verification of test atmosphere concentrations:
yes
Remarks:
determined gravimetrically
Duration of exposure:
4 h
Concentrations:
1820 mg/m³ air (maximum achievable concentration)
No. of animals per sex per dose:
9 animals
Control animals:
no
Details on study design:
The animals were submitted to a necropsy at the end of the observation period.
Statistics:
The average dust concentration was gravimetrically determined.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 1 820 mg/m³ air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: Average dust concentration, gravimetrically determined
Mortality:
No deaths observed
Clinical signs:
other: During the 4-hour exposure period and the subsequent 14-day observation period no toxic symptoms were observed.
Gross pathology:
No substance related gross organ changes were seen.
Other findings:
aerosol concentration: 1820 +/- 69 mg/m³

Applicant's summary and conclusion