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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1995/09/20-1995/10/04
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Similar to OECD Guideline 403 - GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Reference substance name:
Hydrocarbons, C10-C13, aromatics, >1% naphthalene
EC Number:
926-273-4
IUPAC Name:
Hydrocarbons, C10-C13, aromatics, >1% naphthalene

Test animals

Species:
rat
Strain:
other: Crl:CDBR
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
Source: Charles River Laboratories Inc.
Sex: Male (5), Female (5) for each species
Age at study initiation: 7 weeks
Weight at study initiation:
Males: 145-171g
Females: 146 - 177g
Housing: Single housed
Diet (e.g. ad libitum): PMI Feeds, Inc. Certified Rodent Diet #5002 ad libitum during non-exposure period; withheld during exposure
Water (e.g. ad libitum): automatic watering system, ad libitum
Acclimation period: 7d and animals were examined once a day for viability

ENVIRONMENTAL CONDITIONS
Temperature (°F): 68-76
Humidity (%): 40-70%
Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
whole body
Vehicle:
other: unchanged (no vehicle)
Details on inhalation exposure:
The test material was generated using a single barrel Laskin nebulizer. Compressed air was supplied to the nebulizer at 5-7 psi back pressure, producing a droplet aerosol that was mixed with room air and drawn into the exposure chamber. Particle size was determined via a Sierra Instruments Model 210 Cascade Impactor. DATA: Exposure Concentration (average actual): 4778 mg/m3
Exposure Concentration (nominal): 11321 mg/m3
Chamber Size: 150L
ATM Pressure: slightly negative pressure to the room
Temperature: 25°C
Air Flow Rate: 30 (L/min)
Analytical verification of test atmosphere concentrations:
yes
Remarks:
gravimetrically (aerosol), GC/FID (vapour)
Duration of exposure:
4 h
Concentrations:
4778 mg/m3 (analytical)
11321 mg/m3 (nominal))
Chamber Size: 150L
ATM Pressure: slightly negative pressure to the room
Temperature: 25°C
Air Flow Rate: 30 (L/min)
No. of animals per sex per dose:
Male (5), Female (5) for each species
Control animals:
no
Details on study design:
The animals were individually housed in a 150L stainless steel whole body inhalation chamber that was under a slight negative pressure to the room and had an air flow of 30 L/min. The exposure was 4 hours plus equilibration time (~23 min) and air flow, temperature, and humidity were continuously monitored. Animals were observed for mortality and obvious toxic signs at 15 min intervals for the first hour of exposure and then once each hour until the termination of the exposure. Body weights for each animal were recorded prior to exposure and on days 7 and 14. A gross necropsy was performed on every animal.
Statistics:
Mean and Standard Deviation of body weight and body weight change by group and sex.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 4 778 mg/m³ air (analytical)
Mortality:
One male animal was found dead on day 2 post-exposure. This animal was observed as prostrate with wet fur, oral and nasal discharge, wet rales, and little sign of stool or food consumption.
Clinical signs:
other: The majority of abnormalities were noted during the first 2 days of the 14 day observational period. These abnormalities included wet/matted fur, oral/nasal discharge, reddening of the eyelids and extremities, anogenital staining, and alopecia.
Body weight:
All animals gained body weight over their initial values.
Gross pathology:
A dead animal was observed with dark red nasal turbinates and bright red lungs, red material in the stomach mixed with ingesta, wet/matted fur, and nasal discharge. Surviving animals were observed having small seminal vesicles, scabs, red foci in the lungs and thymus. One male and all five females were free of abnormalities.

Applicant's summary and conclusion

Interpretation of results:
not classified
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The LC50 is >4.778 mg/L for aerosolized MRD-95-246. Classification as an acute inhalation toxicant is not warranted under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.
Executive summary:

Five male and five female rats were exposed to 4778 mg/m3 (4.778 mg/L, analytical)/ 11321 mg/m3 (11.3 mg/L, nominal) aerosol of test material MRD-95-246 for 4 hours. Animals were observed for 14 days. One male animal was found dead on day 2 post-exposure.  The majority of abnormalities were noted during the first 2 days of the 14 day observational period.  These abnormalities included wet/matted fur, oral/nasal discharge, reddening of the eyelids and extremities, anogenital staining, and alopecia.  One male and all five females were free of abnormalities by day 14 and surviving animals continued to gain weight through day 14. The LC50 is >4.778 mg/L for aerosolized MRD-95-246. Classification as an acute inhalation toxicant is not warranted under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.