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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:
1995-09-20 to 1995-10-05
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to or similar to guideline study OECD 403: GLP
Justification for type of information:
A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
Cross-reference
Reason / purpose for cross-reference:
read-across: supporting information
Reference
Endpoint:
acute toxicity: inhalation
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
1995-09-20 to 1995-10-05
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to or similar to guideline study OECD 403: GLP
Justification for type of information:
A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across source
Duration of exposure:
h
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5 991 mg/m³ air (analytical)
Exp. duration:
4 h
Remarks on result:
other: No mortalities.
Mortality:
No mortalities occurred.
Clinical signs:
other:
Body weight:
All animals displayed increases in body weight over their initial (Day 0) values.
Gross pathology:
All ten animals were free of internal macroscopic abnormalities at post-mortem examination.
Interpretation of results:
other: Not classified
Remarks:
Criteria used for interpretation of results: EU
Conclusions:
The LC50 for acute inhalation exposure (aerosol atmosphere) to MRD-95-289 is greater than 5991 mg/m3 (5428 mg/m3 aerosol, 562 mg/m3 vapor). This finding does not warrant classification of Isopar M as an acute inhalation toxicant under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.
Executive summary:

This data is being read across from the source study that tested Hydrocarbons, C12-C16, isoalkanes, cyclics, <2% aromatics based on analogue read across.

To assess acute inhalation toxicity, MRD-95 -289 was administered via individual whole-body inhalation chambers for four hours to ten Crl:CDBR rats at a total chamber concentration of 5991 mg/m3 (5428 mg/m3 aerosol, 562 mg/m3 vapor). Animals were observed for fourteen days following exposure. There were no mortality or gross pathological alterations in the animals, with the exception of two animals that displayed scabs and one with a necrotic and truncated tail. Based on the conditions of the study, the LC50 for acute inhalation exposure to an aerosol atmosphere of MRD-95 -289 is greater than 5991 mg/m3.

This finding does not warrant classification of MRD-95 -289 as an acute inhalation toxicant under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

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, C12-C16, isoalkanes, cyclics, < 2% aromatics
IUPAC Name:
Hydrocarbons, C12-C16, isoalkanes, cyclics, < 2% aromatics

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories Inc., Kingston, New York USA
- Age at study initiation: Males, approximately 6 weeks; Females, approximately 7 weeks
- Weight at study initiation: Males, 155 to 168 grams; Females, 157 to 177 grams
- Fasting period before study: none
- Housing: Single housed during the study period. Suspended stainless steel and wire mesh.
- Diet (e.g. ad libitum): Certified Rodent Diet #5002, from PMI Feeds, Inc., Richmond, Indiana, ad libitum, during non-exposure periods. Food withheld while animals were in chamber.
- Water (e.g. ad libitum): Automatic watering system, ad libitum, during non-exposure periods. Water withheld while animals were in chamber.
- Acclimation period: 8 days.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 68-76 degrees F while in animal room; 71-74 degrees F while in exposure chamber
- Humidity (%): 40-70% relative humidity while in animal room; 82-95% relative humidity while in exposure chamber
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark


IN-LIFE DATES: From: 1995-09-21 To: 1995-10-05

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
whole body
Vehicle:
other: unchanged (no vehicle)
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 150 liter stainless steel and acrylic whole-body inhalation exposure chamber.
- System of generating particulates/aerosols: The test atmosphere was generated using a Laskin nebulizer and a 3-neck round-bottom flask as a reservoir for the liquid test material. Compressed air was supplied to the nebulizer at approximately 4-5 psi back-pressure, producing a liquid droplet aerosol within the 3-neck flask. The aerosol was mixed with additional room air and then drawn into the exposure chamber.
- Method of particle size determination: Sierra Instruments Model 210 Cascade Impactor. Preweighed glass fiber filters were used to collect the aerosol on each stage. A bulk estimation technique was employed to characterize the particle size distribution of the test atmosphere. The change in weight of the filter for each stage was measured and the cumulative percent of the sample collected on each stage was calculated. This information plus the stage constants for the impactor were used to calculate the 15.9%, 50.0% and 84.1% particle sizes, the geometric standard deviation, and the estimated percent of the aerosol less than or equal to 1, 10, and 15 microns in size.
- Temperature, humidity, pressure in air chamber:

TEST ATMOSPHERE
- Brief description of analytical method used: Analytical chamber concentrations were determined during each hour of the exposure by drawing a known volume of the test atmosphere through a sample train consisting of a glass-fiber filter for collection of non-volatile aerosol and a charcoal sorbent tube for collection of volatile hydrocarbons (vapor).

Non-volatile aerosol concentrations were first determined gravimetrically by dividing filter weight gain by the sample volume. The filters and the charcoal tubes were then analyzed by GC/FID. Total hydrocarbons and individual hydrocarbons (full scan) were reported for both sample types. Total analytical chamber concentrations were reported as the sum of the gravimetric aerosol and total hydrocarbon vapor results.

PARTICLE SIZA DATA
-Mass median equivalent aerodynamic diameter (50% size): 3.4 microns
-Gravimetric standard deviation: 2.1
-Percent <= 15 microns: 98.0%
-Percent <= 10 microns: 93.3%
-Percent <= 1 micron: 4.6%

Analytical verification of test atmosphere concentrations:
yes
Remarks:
Gravimetrically (aerosol); GC/FID (vapor)
Duration of exposure:
4 h
Concentrations:
5991 mg/m3 (5428 mg/m3 aerosol, 562 mg/m3 vapor)
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Approximately 15 minute intervals during the first hour of exposure and once each hour thereafter through the termination of exposure.
- Necropsy of survivors performed: yes
Statistics:
Means and standard deviations for body weight and body weight change by group and sex

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5 991 mg/m³ air (analytical)
Exp. duration:
4 h
Remarks on result:
other: No mortalities.
Mortality:
No mortalities occurred.
Clinical signs:
other:
Body weight:
All animals displayed increases in body weight over their initial (Day 0) values.
Gross pathology:
All ten animals were free of internal macroscopic abnormalities at post-mortem examination.

Applicant's summary and conclusion

Interpretation of results:
other: Not classified
Remarks:
Criteria used for interpretation of results: EU
Conclusions:
The LC50 for acute inhalation exposure (aerosol atmosphere) to MRD-95-289 is greater than 5991 mg/m3 (5428 mg/m3 aerosol, 562 mg/m3 vapor). This finding does not warrant classification of Isopar M as an acute inhalation toxicant under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.
Executive summary:

To assess acute inhalation toxicity, MRD-95 -289 was administered via individual whole-body inhalation chambers for four hours to ten Crl:CDBR rats at a total chamber concentration of 5991 mg/m3 (5428 mg/m3 aerosol, 562 mg/m3 vapor). Animals were observed for fourteen days following exposure. There were no mortality or gross pathological alterations in the animals, with the exception of two animals that displayed scabs and one with a necrotic and truncated tail. Based on the conditions of the study, the LC50 for acute inhalation exposure to an aerosol atmosphere of MRD-95 -289 is greater than 5991 mg/m3.

This finding does not warrant classification of MRD-95 -289 as an acute inhalation toxicant under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.