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Toxicological information

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:
January 22, 2015 - February 23, 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report Date:
2015

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test type:
acute toxic class method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Test animals

Species:
rat
Strain:
other: Rat (Rattus norvegicus) / CD / Crl: CD(SD)
Sex:
male/female
Details on test animals and environmental conditions:
Species / Strain / Stock:
Rat (Rattus norvegicus) / CD / Crl: CD(SD)

Breeder:
Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany

Age(at start of administration):
Males: approx. 8 weeks
Females: approx. 9 weeks

Body weight(at start of administration):
Males: 247 - 258 g
Females: 228 - 250 g

Selection of species:
In accordance with OECD 436, the rat is the preferred species.

Identification of animals:
By coloured marks and cage label

Group / Number of animals:
One concentration of 3 males and 3 females (limit test)

Satellite animals forinterim necropsy(24-hour sacrifice):
3 males and 3 females

Concentrations:
5.07 mg/L air (limit test) for 4 hours and 5.06 mg/L air (satellite animals) for 4 hours

Duration of experiment:
At least 5 adaptation days
1 test day
2 recovery weeks (limit test)

The females were nulliparous and non-pregnant.
The animals were randomised before use. They were acclimatised to the test apparatus for approx. 1 hour on 2 days prior to testing. The restraining tubes did not impose undue physical, thermal or immobilization stress on the animals.

Diet
Commercial diet, ssniff® R/M-H V1534 served as food. Feeding was discontinued approx. 16 hours before exposure; only tap water was then available ad libitum.
Periodic analysis of the food for contaminants based on EPA/USA is conducted at least twice a year by LUFA-ITL.

Housing
Granulated textured wood was used as bedding material for the cages. The cages were changed and cleaned twice a week.
Periodic analysis of the bedding material for contaminants based on EPA/USA is conducted at least once a year by LUFA-ITL.
During the 14-day observation period, the animals are kept by sex in groups of 3 animals in MAKROLON cages (type III plus) at a room temperature of 22°C±3°C (maximum range) and a relative humidity of 55%±15% (maximum range). Deviations from the maximum range caused for example during cleaning procedures are dealt with in SOPs.
The rooms were lit (about 150 lux at approx. 1.50 m room height) and darkened for periods of 12 hours each.

Drinking water
Drinking water in bottles was offered ad libitum.
Drinking water was examined according to the 'Deutsche Trinkwasserverordnung 2011' [German Regulations on drinking water 2011] by the Hamburger Wasserwerke, 20539 Hamburg, Germany, at least four times a year.

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose/head only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
2.488 µm
Geometric standard deviation (GSD):
2.97
Remark on MMAD/GSD:
The particle size distribution was analysed using a cascade impactor. The Mass Median Aerodynamic Diameter (MMAD) was determined as 2.488 µm (14-day sacrifice) or 2.460 µm (24-hour sacrifice). The Geometric Standard Deviations (GSD)
of the MMAD were calculated as 2.97 (main study, 14-day sacrifice) or 2.96 (satellite animals, 24-hour sacrifice).
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
5.07 mg/L air (limit test) for 4 hours and 5.06 mg/L air (satellite animals) for 4 hours
No. of animals per sex per dose:
3 males and 3 females
Control animals:
yes

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5.07 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No animal died prematurely.
Clinical signs:
other: Under the present test conditions, a 4-hour inhalation exposure to SE7B at a concentration of 5.07 mg/L air revealed slightly reduced motility and slight ataxia on test day 1 immediately after the end of exposure until 60 minutes post exposure, slight to
Body weight:
No influence on body weight gain was observed.
Gross pathology:
Macroscopic changes in the nasal cavity and lungs
Oedematous or oedematous and marbled lungs were observed in all animals of the main study (14-day sacrifice) and in all satellite animals (24-hour sacrifice).

Microscopic changes in the nasal cavity and lungs
Test item-related histopathological changes
The histomorphological examination of the organs (trachea, larynx, lungs and nose) from the acute inhalation toxicity study of SE7B in male and female rats of the satellite rats (24-hour sacrifice) and the main study animals (14 days recovery) did not reveal any morphological lesions which are considered to be test item-related.

Not test item-related histopathological changes
Satellite animals (24-hour sacrifice) and main study animals (14-day sacrifice):
• Nose (five levels):
The nasal cavity of level 1 to 5 revealed a normal squamous epithelium and a normal respiratory epithelium. The normal respiratory epithelium partially containing cilia consisted of three major cell types: the basal cells above the basement membrane, the ciliated epithelial and the secretory goblet cells.
Some rats showed in the respiratory epithelium minimal to mild subepithelial lympho-histiocytic infiltrations or lymphocytic follicles for nose levels 3 to 5.

In all animals a normal olfactory epithelium with 5 to 7 nuclear layers, normal basal cells, olfactory sensory cells and sustentacular cells were observed for nose levels 3 to 5.
There were no morphological differences between the satellite and main study animals.
• Lungs (five levels):
All 5 lung localizations revealed a normal lung structure. A minimal to mild congestion and in one rat a minimal foamy macrophages are coincidental findings and thus are not test item-related.
The trachea of some male and female animals revealed a focal minimal to mild subepithelial lymphoid hyperplasia with normal epithelial cells. The epithelium of the larynx was normal.
There were no morphological differences between satellite and main study animals.
Other findings:
The gravimetric aerosol concentrations of 5.07±0.02 mg (14-day sacrifice) and 5.06±0.02 mg (24-hour sacrifice) SE7B/L air were measured at the animal’s nose.
The particle size distribution was analysed using a cascade impactor. The Mass Median Aerodynamic Diameter (MMAD) was determined as 2.488 μm (14-day sacrifice) or 2.460 μm (24-hour sacrifice). The Geometric Standard Deviations (GSD) of the MMAD were calculated as 2.97 (main study, 14-day sacrifice) or 2.96 (satellite animals, 24-hour sacrifice).

Any other information on results incl. tables

The mean actual exposure concentrations in the breazing zone, the nominal concentration (total amount of the substance fed into the inhalation equipment divided by volume of air), MMADs and GSDs of SE7B were as follows:

Group
nominal concentration  gravimetric
(actual)
concentration 
mass median aerodynamic diameter
(MMAD)
geometric standard deviation
(GSD)
Relation of actual to nominal concentration
(assumed density = 1 g/mL)
[μL/L air]  [mg/L air]  [μm] 
main study, 14-day sacrifice  33.33 5.07 2.488 2.97 0.15
satellite animals, 24-hour sacrifice  33.33 5.06 2.46 2.96 0.15

Conclusion

Under the present test conditions, the LC50 value (males and females combined) for rats following inhalation of SE7B for 4 hours was determined as follows (gravimetric concentration):

LC50: > 5.07 mg SE7B/L air

According to the Globally Harmonized Classification System (GHS) the test item should be unclassified (as LD50 > 5 mg/L air). Based on the results of the macroscopic and histopathological investigations, SE7B appears to be slightly irritating for the respiratory epithelium, however, no histological changes could be observed. The changes were almost completely reversible during the 14-day recovery period.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the present test conditions, the LC50 value (males and females combined) for rats following inhalation of SE7B for 4 hours was determined as follows (gravimetric concentration):
LC50: > 5.07 mg SE7B/L air
According to the Globally Harmonized Classification System (GHS) the test item should be unclassified (as LD50 > 5 mg/L air). Based on the results of the macroscopic and histopathological investigations, SE7B appears to be slightly irritating for the respiratory epithelium, however, no histological changes could be observed. The changes were almost completely reversible during the 14-day recovery period.