Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to OECD guidelines No. 436 “Acute Inhalation Toxicity – Acute Toxic Class Method” and in accordance with GLP.
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report Date:
2011

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)
Principles of method if other than guideline:
Guideline followed.
GLP compliance:
yes (incl. certificate)
Test type:
acute toxic class method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report)
- Physical state: White powder
- Analytical purity: 99.5%
- Storage condition of test material: Room temperature in the dark.

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories UK Ltd, Oxon, UK.
- Age at study initiation: 8-12 weeks (All the females were nulliparous and non-pregnant)
- Weight at study initiation: 200 - 350 g
- Fasting period before study: overnight fasting immediately before dosing.
- Housing: The animals were housed in groups of up to 3 by sex in suspended solid-floor polypropylene cages furnished with woodflakes.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 Deg C
- Humidity (%): 30-70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light.

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
clean air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: SAG 410 Solid Aerosol Generator
- Exposure chamber volume: 30 liters
- Method of holding animals in test chamber: Each rat was individually held in a tapered, polycarbonate restaining tube fitted onto a single tier of the exposure chamber and sealed by means of a rubber "O" ring. Only the nose of each animal was exposed to the test atmosphere.
- Source and rate of air: Clean compressed air was supplied by means of a Air compressor at 60L/min
- System of generating particulates/aerosols: A dust atmosphere was produced from the test item using SAG 410 Solid Aerosol Generator, connected to a metered compressed air supply.
- Method of particle size determination: The particle size of the generated atmosphere inside the exposure chamber was determined three times during the exposure period using a Marple Personal Cascade Impactor. This device consisted of six impactor stanges (8.8, 5.8, 3.6, 1.9, 0.79 and 0.33 µm cut points) with stainless steel collection substrates and a back up glass fibre filter, housed in an aluminium sampler. The sampler was temporarily sealed in a sampling port in the animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through it using a vacuum pump.
The collection substrates and backup filter were weighed before and after sampling and the weight of test item, collected at each stage, calculated by difference.
The mean amount for each stage was used to determine the cumulative amount below each cut-off point size. In this way, the proportion (%) of aerosol less than 8.8, 5.8, 3.6, 1.9, 0.79 and 0.33 µm was calculated.
The resulting values were converted to probits and plotted against Log10 cut-point size. From this plot, the Mass Median Aerodynamic Diameter (MMAD) was determined (as the 50% point) and the geometric standard deviation was calculated. In addition the proportion (%) of aerosol less than 4 µm (considered to me inhalable fraction) was determined.
- Temperature, humidity, pressure in air chamber: The temperature and relative humidity inside the exposure chamber were measured by an electronic thermometer/ humidity meter located in a vacant port in the animals’ breathing zone of the chamber and recorded every thirty minutes throughout the four-hour exposure period.

TEST ATMOSPHERE
- Brief description of analytical method used: The actual chamber concentrations was measured at regular intervals during the exposure period. The gravimetric methods used glass fibre filters placed in a filter holder. The holder was temporarily sealed in a vacant port in the exposure chamber in animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through the filter using a vacuum pump.
Each filter was weighed before and after sampling in order to calculate the weight of collected test item. The difference in the two weights, divided by the volume of atmosphere sampled, gave the actual chamber concentration.
The nominal chamber concentration was calculated by dividing the mass of the test item used by the volume of air passed through the chamber.
The nominal concentration was 149% of the actual mean achieved atmosphere concentration and shows that keeping the aerosol airborne was relatively straightforward.
- Samples taken from breathing zone: yes

VEHICLE
- Composition of vehicle (if applicable): No Vehicle used.


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: The particle size of the generated atmosphere inside the exposure chamber was determined three times during the exposure period using a Marple Personal Cascade Impactor. This device consisted of six impactor stanges (8.8, 5.8, 3.6, 1.9, 0.79 and 0.33 µm cut points) with stainless steel collection substrates and a back up glass fibre filter, housed in an aluminium sampler. The sampler was temporarily sealed in a sampling port in the animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through it using a vacuum pump.
The collection substrates and backup filter were weighed before and after sampling and the weight of test item, collected at each stage, calculated by difference.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The mean amount for each stage was used to determine the cumulative amount below each cut-off point size. In this way, the proportion (%) of aerosol less than 8.8, 5.8, 3.6, 1.9, 0.79 and 0.33 µm was calculated.
The resulting values were converted to probits and plotted against Log10 cut-point size. From this plot, the Mass Median Aerodynamic Diameter (MMAD) was determined (as the 50% point) and the geometric standard deviation was calculated. In addition the proportion (%) of aerosol less than 4 µm (considered to me inhalable fraction) was determined.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: A target concentration of 5.0 mg/L was used for the exposure. As the mean achieved concentration was 103% of target and no deaths occured, no further levels were required.
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
5.13 mg/L
No. of animals per sex per dose:
3 male and 3 female exposed to 5.13 mg/L concentartion.
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Individual bodyweights were recorded on arrival, prior to treatment on the day of exposure and on days 1, 3, 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, Gross pathology.
Statistics:
None

Results and discussion

Preliminary study:
A target concentration of 5.0 mg/L was used for the exposure. As the mean achieved concentration was 103% of target and no deaths occured, no further levels were required.
Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5.13 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: A target concentration of 5.0 mg/L was used for the exposure.
Mortality:
There were no deaths.
Clinical signs:
other: Common abnormalities noted during the study included increased respiratory rate, hunched posture, pilo-erection and wet fur (these observations were considered not to be associated with neurotoxicity). Animals recovered to appear normal on day 6 post-expo
Body weight:
All male animals and twofemales exhibited slight bodyweight losses or showed no bodyweight gain on the first day post-exposure. 1 male and 1 female animal exhibited bodyweight losses from days 3 to 7, a further female exhibited bodyweight loss during the first week of recovery. Reasonable bodyweight development was noted in all other animals during the recovery period.
Gross pathology:
No macroscopic abnormalities were detected amongst animals at necropsy.
Other findings:
None

Any other information on results incl. tables

None

Applicant's summary and conclusion

Interpretation of results:
practically nontoxic
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
No deaths occurred in a group of six rats exposed to a mean achieved atmosphere concentration of 5.13 mg/L for 4 hours. It was therefore considered that the acute inhalation median lethal concentration (4 hr LC50) of test item was >5.13mg/L.
Executive summary:

The study was performed to assess the acute inhalation toxicity of the test item in the Wistar strain rat following OECD TG No. 436. A group of 6 RccHan WIST strain rats (3 males and 3 females) was exposed to a dust atmosphere. The animals were exposed for four hours using a nose only exposure system, followed by a 14 day observation period.

Mortality: There were no deaths.

Clinical observations: Common abnormalities noted during the study included increased respiratory rate, hunched posture, pilo-erection and wet fur (these observations were considered not to be associated with neurotoxicity). Animals recovered to appear normal on day 6 post-exposure.

Bodyweight: All male animals and twofemales exhibited slight bodyweight losses or showed no bodyweight gain on the first day post-exposure. 1 male and 1 female animal exhibited bodyweight losses from days 3 to 7, a further female exhibited bodyweight loss during the first week of recovery. Reasonable bodyweight development was noted in all other animals during the recovery period.

Necropsy: No macroscopic abnormalities were detected amongst animals at necropsy

CONCLUSION: No deaths occurred in a group of six rats exposed to a mean achieved atmosphere concentration of 5.13 mg/L for 4 hours. It was therefore considered that the acute inhalation median lethal concentration (4 hr LC50) of test item was >5.13mg/L.