Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 November 2007 to 15 November 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Qualifier:
according to guideline
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1300 (Acute inhalation toxicity)
GLP compliance:
yes
Test type:
acute toxic class method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
impurity
Test material form:
solid: particulate/powder
Details on test material:
The test material is a UVCB substance.
Specific details on test material used for the study:
Identification AD-2000
Form White powder
Batch L-620150
Storage At room temp in the dark
Stability under storage condition Stable
Expiry date 1 January 2009

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
Species: Rat: Wistar Crl: WI (outbred, SPF-Quality)
Recognised by international guidelines as the recommended test system
(e.g. OECD, EC).

Number of animals: 5 males and 5 females (females were nulliparous and non-pregnant) per exposure level.

Age and body weight: Young adult animals were selected (11 weeks old).
Animals used within the study were of approx. the same age and body weight variation did not exceed +/- 20% of the sex mean.

Conditions
Animals were housed in a controlled environment, in which optimal conditions were considered to be approximately 15 air changes per hour, a temperature of 21.0 ± 3.0°C (actual range: 20.4- 22.6°C), a relative humidity of 30- 70% (actual range: 43- 63%) and 12 hours artificial fluorescent light and 12 hours darkness per day.
During exposure the mean temperature and relative humidity were 20.8°C and 44%.

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
>= 3.6 - <= 3.8 µm
Remark on MMAD/GSD:
The cumulative particle size distribution showed an elongated tail at the smaller particle size. It was concluded that the particle size distribution was not log-normally distributed and a geometric standard deviation (GSD) could not be calculated.
Details on inhalation exposure:
Animals were exposed to the test material via the inhalatory route. For this purpose the animals were placed in restraining tubes, which were connected to the exposure chamber. The design of the exposure chamber was based on the flow past nose-only inhalation chamber (Am. Ind.
Hyg. Assoc. J. 44(12): 923-928, 1983). The chamber consisted of 4 animal sections with 8 animal ports each. The number of open animal ports was adapted to the air flow in such a way that at each animal port the theoretical air flow was approximately 2.0 L/min, which ensures an adequate oxygen supply to the
test animals. The inlet of the test atmosphere was located in the top section and the outlet was located in the bottom section. The direction of the flow of the test atmosphere guaranteed a freshly generated atmosphere for each individual animal. All components of the exposure chamber which could come in contact with the test material were made of stainless steel, glass, rubber or plastic. To avoid exposure of the personnel and contamination of the laboratory the exposure chamber was placed in a fume hood, which maintained a slight negative pressure.

An aerosol was generated by administering the test substance to a stream of pressurized air (approximately 33.8 L/min) by means of a combination of a spiral feeder and an air mover. Subsequently the aerosol was led through the exposure chamber. From the exposure chamber the test atmosphere was passed through a filter before it was released to the exhaust of the fume hood.
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
The mean actual concentration was 5.9 ± 1.3 mg/L. The nominal concentration was 17.9 mg/1. The generation efficiency (ratio of actual and nominal concentration) was 33%.
No. of animals per sex per dose:
5 males and 5 females
Details on study design:
Target concentrations were based on the concentrations specified in the Globally harmonized system of classification of chemicals (GHS), United Nations, New York and Geneva, 2003. For this reason five animals of each sex were exposed in a limit test for 4 hours to a target concentration of the test substance of 5 mg/L.
For exposure the animals were restrained in polycarbonate restraining tubes. After restraining the tubes were connected to the exposure chamber. Twenty three minutes hereafter the generation of the test atmosphere was started. The exposure time lasted 4 hours.
Observations
3 times during exposure
Mortality/viability checked twice daily.
Animals were observed for 15 days.
Clinical signs were checked twice at 1 and 3 hours during exposure on the day of dosing and once daily thereafter until day 15. The sysmptoms were grades.
All animals were sacrificed at the end of the observation period by an intraperitoneal injection of sodium pentobarbital at least 250 mg sodium pentobarbitalIkg
and subsequently exsanguinated. All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities
were recorded. Particular attention was given to any changes in the respiratory tract The right kidney of one male and the caecum of one female were collected for future histopathology.
Statistics:
No statistical analysis was performed.

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No mortality
Clinical signs:
other: During exposure no clinical signs were noted. After exposure the following clinical signs were noted: hunched posture, piloerection, laboured respiration, slow breathing, rales, chromodacryorrhoea, brown staining of the head and/or snout. The surviving
Body weight:
Body weight loss or reduced weight gain was shown by the majority of the animals during the first week after exposure. During the second week after exposure weight gain had recovered in the majority of the animals. The mean body weight gain shown by the animals over the study period was considered to be similar to that expected of normal untreated animals of the same age and strain.
Gross pathology:
No abnormalities were found at macroscopic post mortem examination of the animals.

Incidental findings included pelvic dilatation of the right kidney in one male and reddish discolouration of the caecum in one female. These findings are occasionally seen among rats of this age and strain and were therefore considered not related to treatment.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The inhalatory LC50 4h value of the test substance in Wistar rats was established to exceed 5 mg/L.