2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole)

Endpoint summary

Description of key information

The oral LD50 was determined to be greater than 10000 mg/kg bw. Responses to the administered test substance were negligible. No deaths occurred at any dosage levels used. The LC50 by inhalation determined after an observation period of 14 days in rats of both sexes, exposed to the substance for four hours is greater than 1820 mg/m3 (highest concentration possible). No toxic symptoms were observed.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1963

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

no data on sex, limited details on animal husbandry, limited details on test compound, observation period not specified, no details on examinations

GLP compliance:

no

Remarks:

prior to GLP

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: about 120 g

Route of administration:

oral: gavage

Vehicle:

not specified

Doses:

1000, 3000, 6000, 10000 mg/kg

No. of animals per sex per dose:

5 animals (sex not specified)

Control animals:

no

Sex:

not specified

Dose descriptor:

LD50

Effect level:

> 10 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: no mortality occurred

Mortality:

none

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

10 000 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

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

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

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

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.

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

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

1 820 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Acute toxicity: oral route

In an acute toxicity study (similar to OECD401) the range of mortality following oral administration of the test substance was assessed. Groups of 5 rats were treated by gavage with the test article at dose levels of 1000, 3000, 6000 and 10000 mg/kg body weight. The LD50 was determined to be greater than 10000 mg/kg bw. Responses to the administered test substance were negligible. No deaths occurred at any dosage levels used.

 

Acute toxicity: inhalation route

Aim of the study was to provide information on health hazards likely to arise from short-term exposure by the inhalation route. The test substance was tested by the exposure of albino rats (9 animals per sex) to an aerosol generated from this product. The study is equivalent to the OECD guideline 403. A concentration of 1820 +/- 69 mg/m³ (highest achievable concentration) was tested. During the 4-hour exposure period and the subsequent 14-day observation period no toxic symptoms were observed. No substance related gross organ changes were seen. The LD50 of the test substance determined after an observation period of 14 days in rats of both sexes, exposed to the substance for four hours is therefore greater than 1820 mg/m³ air.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008 (CLP). As a result the test substance is not considered to be classified for acute oral toxicity and for acute inhalation toxicity under Regulation (EC) No 1272/2008.