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Diss Factsheets

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
6th August 2018 until 13th August 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: Acute Inhalation Toxicity - acute class method (436) published by the Ministry of Environmental Protection of People's Republic of China in 2013
GLP compliance:
yes
Test type:
acute toxic class method
Limit test:
no

Test material

Specific details on test material used for the study:
Batch No. BO1801B009
Concentration: 97.4%
Physical properties: White powder without lumps

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
Test System
Species: Rat
Strain: Sprague Dawley Grade: SPF
Supplier: Beijing Vital River Laboratory Animal Technology Co., Ltd. Animal Production License: SCXK. (Jing) 2016-0006
Animal Certificate No.: 11400700321619
Number of Animals: 6 animals (3 males and 3 females) were ordered and used. The females were nulliparous and non-pregnant.
Age and Body Weight: The age was between 67-73 days, and the body weights were between 310-336 g for male rats and 232-272 g for female rats. The
body weights were within ±20% of the mean weight for each sex when exposure.

Physical Examination and Acclimatization: A physical examination, weighing and marking on the hair and cage card identifying was made in 24 hours after animals' arrival. After the physical examination more than 5 days' acclimatization period started. Animals were acclimated to the restraining tubes twice prior to dosing in order to minimize stress and uncomfortableness about restraining tubes. First pre-adaption was about 1 h. Second pre-adaption was about 2 h. No abnormalities were found during both restraining. One or two animals were paired housed per cage during the acclimatization period.

Test conditions:
Husbandry: Animals were housed in Room Al20-1 of the facility. Animals were raised in suspended, stainless steel cages on cage racks. There were 10 cages per layer, and 4 layers per rack. Animals were housed individually after exposure.

Environmental Controls: The temperature and humidity were automatically controlled and recorded. The target value of animal room temperature was 19°C -25°C,
of the relative humidity was 40%- 70% and light cycle was 12 hour light and 12 hour dark.

Food and Water: Animals were provided with rodent complete nutrition pellet diet supplied by Beijing keaoxieli Feed CO., LTD. Analysis report of diet was provided by the supplier. Water was purified using the HT-ROlOOO purity system. Drinking water was routinely analyzed. Diet and drinking water were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study. During the test, diet and water were available to the animals ad libitum except exposure and pre-adaption.

Animal Welfare: The animal use for this study complies with the national animal welfare laws and regulations (instructive notions with respect to caring for laboratory animals) (2006, PRC Ministry of Science). The animal care and use activities required for conduct of this study were reviewed and approved by the testing facility Animal Care and Use Committee (IACUC).

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
snout only
Mass median aerodynamic diameter (MMAD):
ca. 1.85
Geometric standard deviation (GSD):
ca. 1.58
Remark on MMAD/GSD:
The mass median aerodynamic diameters (MMAD) for two times measurement were 1.85µm and 2.13µm, respectively. The geometric standard deviations (GSD) were 1.58 and 1.68, respectively. The aerodynamic particle sizes less than 4 micron (mass%) for two times measurement were both 99.92% and 99.69%
Details on inhalation exposure:
Test Equipment and Administration Method:

Equipment: HOPE-MED 8052H dynamic snout only aerosol inhalation instrument was used.

Atmosphere Generation System: The test item was aerosolized using a stainless steel aerosol generation system. The test item was infused into generation system through peristaltic pump and mixed with compressed air. Target concentration was achieved by adjusting air flow rate and pump infusion velocity.

Exposure Method: Test item preparation: Test item had been grinded before exposure. Before exposure, each rat was restrained in a confined transparent polycrylic tube. The exposure tubes were installed in the portholes of the inhalation chamber and the chamber was sealed up. Filtered and compressed air was mixed with quantitative test item and aerosol was sent to exposure chamber (0.04m^3). The test item moving speed and exposure airflow rate had been adjusted. The aerosol had been continuously generated from generation system on the top of the chamber with an aerosol producer. A slight negative pressure was maintained in outer plenum of chamber to prevent leakage of the test substance into the surrounding area. The exhausted air was removed from the outlet at the bottom of the chamber to absorption unit.

Concentration Trial: Before commencement of the exposure, technical trial had been conducted (without animals) using the inhalation system. The two concentrations' error were within + 20%, so the exposure had been done.
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
>= 4 h
Concentrations:
5020 +/- 102mg/m^3
No. of animals per sex per dose:
1 dose at 5,000 mg/m^3: 3 males & 3 females in group
Control animals:
no
Details on study design:
Clinical Observations:
Clinical observations were recorded once during the exposure and twice with more than 30 minutes interval after exposure on the exposure day and then once daily for up to the end observation. Observation and record was conducted including animal fur changes, eyes and mucous membranes, and also respiratory, circulatory, autonomic and central nervous systems, and somatomotor activity and behaviour patterns. Attention was directed to tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.

Body Weights:
The animals were weighed in the first 24 hours after arrival, on the day of exposure prior to exposure (day 0), and on day 1, day 3, day 7 and day 14.

Necropsy:
All surviving animals were dissected at the end of the study after anesthetizing with C02 inhalation and killed by bloodletting. Nose, pharynx, larynx, trachea and
lung were examined. The necropsy included following examinations such as the external features of the carcass, external body orifices, the abdominal, thoracic and their contents of all animals, and the location, size, hardness and the color. No abnormalities were found in female and male animals at the gross necropsy, so histopathological examination was not performed.

Evaluation of Data:
Animal number, sex, bodyweight, necropsy and histopathology abnormal findings were summed up. The mean and standard deviations of body weight at different times were calculated.
The inhalation toxicity LC50 range was found. According to GHS criteria for the acute inhalation toxicity the test item category was given. Because unit of LC50 was mg/m3, the LC50 divided by 1000 was converted to mg/L units when test item classification was conducted.

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5 020 mg/m³ air
Based on:
test mat.
Remarks on result:
other: 5020 +/- 102mg/m^3
Mortality:
No animals were found dead during test period and the mortality was zero.
Clinical signs:
other: No abnormalities were found during the whole observation period
Body weight:
No abnormalities were found during the whole observation period
Gross pathology:
No abnormalities were found in female and male animals at the gross necropsy.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The acute inhalation LC50 in SD rate for E Stage 3 intermediate is more than 5020 +/- 102mg/m^3 and it is classified as "unclassified" according to GHS classification