222 OP

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jan - Feb 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP conform guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: appox. 11 weeks
- Weight at study initiation: 309 g (males), 194 g (females)
- Housing: three animals per Makrolon type IV cage
- Diet (e.g. ad libitum): pelleted rodent diet (SM R/M-Z from SSNIFF Spezialdiäten GmbH, Germany), ad libitum except during exposure to the test substance
- Water (e.g. ad libitum): tap water, ad libitum except during exposure to the test substance
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 - 24°C
- Humidity (%): 40 - 70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 20 Jan To: 3 Feb 2014

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

- Exposure chamber
The design of the exposure chamber is based on the flow past nose-only inhalation chamber. The chamber consisted of three animal sections with eight animal ports each. Each animal port had its own atmosphere inlet and exhaust outlet. The animals were placed in restraining tubes and connected to the animal ports. The number of animal sections and number of open inlets were adopted to the air flow in such way that at each animal port the theoretical air flow was at least 1 L/min, which ensures an adequate oxygen supply to the animals. The main inlet of the test atmosphere was located at the top section and the main outlet was located at 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 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 at a slight negative pressure.

- Test atmosphere generation
Administering the test substance to a stream of pressurized air using a combnation of a durst feeder and air mover generated an aerosol. The aerosol was passed through the exposure chamber. The mean total airflow was 27 L/min. From the exposure chamber the test atmosphere was passed through a filter before it was released to the exhaust of the fume hood.

- Test atmosphere characterisation

(A) Nominal concentration
The nominal concnetration was caculated by dividing the amount of test substance used by the volume of pressurized air (average air flow times exposure time) entering the exposure chamber used for exposure of the animals. Due to the small volume of the exposure chamber the equilibrium time was negligible. The volmue of air was calculated from the average air flow (measured by means of thermal mass flow meters and was recorded regularly, preferably in 30 min intervals) and the exposure time.

(B) Actual concentration
The actual concentration was determined 25 times during the exposure period. Samples were drawn from the test atmosphere through a tube in one of the free animal ports of the middle section of the exposure chamber. Samples were drawn through a glass fiber filter. The collected amount of the test substance in the air sample was measured gravimetrically. Sample volumes were measured by means of a dry gas meter.
Subsequently the time-weighted mean concnetration with the standard deviation was calculated.

(C) Particle size characterization
The particle size distribution was characterized twice during the exposure period. The samples were drawn (2 L/min) from the test atmosphere through a tube mounted in one of the free animal ports of the middle section of the exposure chamber. The samples were collected with an 8 stage Marple personal cascade impactor containing fiber glass filters amd a fiber glass back-up filter were measured gravimetrically. Subsequently the Mass Median Aerodynamic Diameter (MMAD) and the Geometric Standard Deviation (GSD) were determined.

(D) Stability monitoring
It was considered that the opacity of the test atmosphere could not be reliably monitored by means of an aerosol monitoring system. An indication of the stability of the test atmosphee was obtained from the concentration measurements, which were equally distributed over time.

(E) Temperature and relative humidity
The temperature and relative humidity were measured with a humidity and temperature indicator and were recorded after the animals were placed in the experimental set-up and at 30 min intervals after initiation of the exposure. The probe was inserted in a tube mounted in one of the free animal ports of the middle section of the exposure chamber. The temperature of the atmosphere was between 20.9 and 21.0°C and relative humidity was between 28 and 32%. These conditions were considered appropriated for this relatively short 4 hours exposure duration.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5 mg/L (target concentration)

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Mortality/Viability: twice daily
Clinical signs: three times during exposure for mortality, behavioural signs of distress and effects on respiration (during exposure); on day 1, one and three hours after exposure and once daily thereafter until day 15. The symptoms were graded according to fixed scales and the time of onset, degree and duration recorded (after exposure)
Body weights: days 1 (pre-administration), 2, 4, 8 and 15
- Necropsy of survivors performed: yes, all animals assigned to the study were subjected to necropsy and description of all internal macroscopic abnormalities were recorded. Particular attention was given to any changes in the respiratory tract.

Statistics:

not mandatory

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.1 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality occured.

Clinical signs:

other: During exposure, slow and shallow breathing was seen in all animals. After exposure no clinical signs of systemic toxicity were noted.

Body weight:

The body weight gain in all males and one female was within the range expected for rats of this strain and age used in this type of study. Two females showed body weight loss during the first week and one female did not gain weight during the second week while the other did gain weight.

Gross pathology:

No abnormalities were found at macroscopic post mortem exmination of the animals.

Other findings:

none

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

Migrated information

Conclusions:

The inhalatory LC50 value of the test item in Wistar rats was established to exeed 5 mg/L. Based on these results the test substance does not have to be classified and has no obligatory labelling requirement for acute inhalation toxicity.

Executive summary:

Assessment of acute inhalation toxicity in the rat (acute toxic class method)

The study was carried out according to OECD guideline 436. The test substance was administered as an aerosol by inhalation for 4 hours to one group of three male and three female Wistar rats. Animals were subjected to dauly observations and determination of body weights on days 1, 2, 4, 8 and 15. Macroscopic examination was performed after terminal sacrifice (day 15). The mean actual concentration was 5.1 +/- 0.13 mg/L. The nominal concentration was 15.6 mg/L. The generation efficiency (ratio of actual and nominal concentraion) was 33%. The concentration measurements equally distributed over time showed that the substance was sufficiently stable. The Mass Median Aerodynamic Diameter (MMAD) and geometric standard deviation (gsd) were determined twice. The MMAD was 3.4 µm (gsd 2.1) and 3.5 µm (gsd 2.1).

No mortaliy occurred. During exposure, slow and shallow breathing was seen in all animals. After exposure, no clinical signs of systemic toxicity were noted. The body weight gain in all males and one female was within the range expected for rats of this strain and age used in this type of study. Two females showed weight loss during the first week and one female did not gain weight during the second week while the other did gain weight. No abnormalities were found at macroscopic post mortem examination of all animals.

The inhalatory LC50, 4h value in Wistar rats was established to exceed 5.1 mg/L.