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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:
13 April 1998 - 05 May 1998
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was conducted in complaince with GLP, however no official test guideline was quoted. The methodology employed is essentially compatible with OECD test guideline 403, however as no justification was given for why the maximum possible airborne concentration of test substance was so much lower than the concentration for a limit test, the data cannot be considered reliable without restrictions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1988

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
yes
Remarks:
: no justification was given for why the maximum possible airborne concentration of test substance was so much lower than the concentration for a limit test, the data cannot be considered reliable without restrictions.
GLP compliance:
yes
Remarks:
The study report contains a statement of GLP compliance signed by the Study Director and a statement of Quality Assurance, however no certificate of GLP compliance issued by an independant authority was included.
Test type:
fixed concentration procedure
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Unifoam AZ SO-NL
- Physical state: Yellow powder
- Analytical purity: 100%
- Purity test date: Not reported.
- Lot/batch No.: Not reported.
- Expiration date of the lot/batch: Not reported.
- Stability under test conditions: Stable.
- Storage condition of test material: Stored in the dark at room temperature.

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River UK Limited, Manston Road, Margate, Kent, England.
- Age at study initiation: 6 weeks (males) and 8 weeks (female) old.
- Weight at study initiation: Approximately 200 g at study initiation.
- Fasting period before study: None reported.
- Housing: 5 rats of like sex per cage housed in polypropylene cages with wire mesh tops and floors.
- Diet (e.g. ad libitum): Free access to a measured excess amount of food (Labsure LAD 1).
- Water (e.g. ad libitum): Free access to tap water.
- Acclimation period: At least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 22°C.
- Humidity (%): Mean humidity = 50%.
- Air changes (per hr): Not reported.
- Photoperiod (hrs dark / hrs light): Not reported.

IN-LIFE DATES: From: 21 April 1988 (Date of dosing / exposure) To: 05 May 1998

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
whole body
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Perspex chamber with square cross-section and pyramidal top
- Exposure chamber volume: Approximately 120 Litres
- Method of holding animals in test chamber: Rats were held in stainless steel mesh partitioned to provide 10 individual animal compartments.
- Source and rate of air:Clean, dry compressed air; source not specified.
- Method of conditioning air: Not reported.
- System of generating particulates/aerosols: Wright dust generator connected to a glass elutriation column to reduce the amount of non-respirable particulate in the aerosol.
- Method of particle size determination: Andersen mini-sampler
- Treatment of exhaust air: Not specified
- Temperature, humidity, pressure in air chamber: Temperature and humidity were recorded, but not included in the report.

TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric analysis of air samples drawn through glass fibre filters.
- Samples taken from breathing zone: yes

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

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: Refer to table in "Any other information".
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): Not calculated.
Analytical verification of test atmosphere concentrations:
yes
Remarks:
Gravimetric analysis only.
Duration of exposure:
4 h
Concentrations:
Mean concentration by analysis = 0.521 mg/L.
No. of animals per sex per dose:
5
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observed for clinical signs continuously throughout exposure period and then twice daily during the observation period. Bodyweight measured daily.
- Necropsy of survivors performed: yes
- Other examinations performed: food consumption and lung weights.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 0.52 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No rats died during the study.
Clinical signs:
other: Partial closing of the eyes and yellow discolouration of the fur was seen in rats exposed to UNIFOAN AZ SO-NL . Restless behaviour was seen in a proportion of the rats during the first 30 minutes of exposure to the test substance. Test substance residue
Body weight:
There were no effects on bodyweight following exposure to the test substance.
Gross pathology:
There were no macroscopic abnormalities in the rats exposed to the test substance and no abnormalities in the control rats.
Other findings:
- Organ weights: The lung weight to bodyweight ratio was determined for all rats. The ratio was considered to be within normal limits for all rats.
- Histopathology: There were no histological findings that could be attributable to exposure to the test substance.

Applicant's summary and conclusion

Conclusions:
The 4-hour LC50 was estimated to be in excess of 0.52 mg/L of air. This was the highest airborne concentration that could be produced using the procedures employed.
Executive summary:

An acute toxicity study was conducted to assess the acute toxicity of the test substance UNIFOAM AZ SO-NL by inhalation exposure (HLS 1988, OCI 43/881087). The study was conducted in compliance with GLP.

Five male and five female rats were exposed by whole body exposure to an atmosphere containing the test material as an airborne dust for an exposure period of four hours. A concurrent control group was exposed in a similar fashion to untreated air. Following the exposure process, animals were observed for 14 days, sacrificed, then a necroscopic examination performed.

There were no deaths during the study. Test substance residues were seen on the fur of most of the exposed rats for 3 days following exposure; all rats were normal by day 7 of the observation period. Body weight gains and the ratio of lung weight to bodyweight were unaffected by exposure to the test substance, and no macroscopic or microscopic abnormalities were seen during pathology. Analysis of the test atmosphere determined that the mean atmospheric concentration of the test substance during the exposure period was 0.52 mg/L.

The 4-hour LC50 was estimated to be in excess of 0.52 mg/L of air. This was the highest airborne concentration that could be produced using the procedures employed.