Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2000-01-06 until 2000-0218
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline compliant study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
1981
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
Version / remarks:
1992
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Ltd, Stone Ridge (Kingston), NY
- Age at study initiation: 46 - 49 days
- Weight at study initiation: males: 229 (+/-7) g; females: 163 (+/-5) g
- Housing: singly, suspended, stainless-steel, wire mesh cages
- Diet: Certified Rodent Diet (Purina Roden Chow #5002, pellets, ad libitum
- Water: drinking water, ad libitum, regulary analysed
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 20.9- 24.3°C
- Humidity: 41.4-55.2 %
- Photoperiod: 12 hours of artificial light

Administration / exposure

Route of administration:
inhalation
Type of inhalation exposure:
nose/head only
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: past nose-only units (CH Technologies, Westwood, NJ)
- Method of holding animals in test chamber: Restraining tubes
- Source and rate of air: hight dose groups: filtered, conditioned, exterior air; mid and low dose groups: filtered compressed air, flow rate of 8.6 - 10.6 L/min
- Method of conditioning air: filtering
- System of generating vapour: evaporation - airflow above surface of the test substance
- Temperature, humidity, pressure in air chamber: 19.0 - 26.0°C, 43 - 75%, ambient pressure, respectively
- Air flow rate: 8.6 - 10.6 L/min
- Air change rate: 86 to 106 air changes per hour
- Method of particle size determination: Micro Laser Particle Counter (model μLPC-301, Particle Measuring Systems, Inc., Boulder, CO)

TEST ATMOSPHERE
- Brief description of analytical method used: GC/FID and multipositional air sampling and analysis system.
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
4.48 mg/L (highest attainable concentration - analytically verified)
2.5 mg/L (analytically verfified)
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
Observations
Rats were observed hourly during exposure for clinical signs of toxicity. However, due to the restraint of the animals in tubes, the during-exposure observations were limited to changes in respiration, eyes, and mucous membranes. Clinical examinations (were conducted before and after exposure and on each subsequent morning. Moribundity and mortality observations were conducted on subsequent weekday afternoons. On weekends, afternoon observations were not performed. Observations included, but were not limited to, examination of the hair, skin, eyes, mucous membranes, motor activity, feces, urine, respiratory system, circulatory system, autonomic nervous system, central nervous system, and behaviour patterns.

Body Weight Determinations
Body weights were measured on Days 0 (pre-exposure), 7, and 14.

Blood Collection and Euthanasia
Animals were fasted overnight beginning after the last exposure. The following day, animals were anesthetized with Isoflurane and blood was collected from the posterior vena cava. The blood was placed into vacutainer tubes and allowed to clot for analyses of serum. Other tubes containing an anticoagulant were used for analyses of whole blood samples. Blood smears were also prepared for blood cell counts. Following blood collection, the animals were euthanatized by exsanguination. Animals were bled and euthanatized in a random order based on a computer-generated list.

Necropsy
At the completion of the 14-day observation period, all animals were anesthetized with isoflurane, exsanguinated by severing the posterior vena cava, and necropsied.
Statistics:
Not applicable

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 4.48 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No mortalities occurred.
Clinical signs:
other: On the day of exposure (Day 0) for the high-concentration group, one male rat had minor porphyrin discharges around the nose, minimal to moderate red discoloration of the hair was observed for two male and two female rats, and minimal to minor unkempt hai
Body weight:
All animals gained weight during both weeks of the study.
Gross pathology:
No test substance-related changes were observed at necropsy, and no tissues were collected for microscopic examination.
Other findings:
none

Applicant's summary and conclusion