Hydrocarbons, C15-16

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

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: During exposure, observed abnormalities included wet/matted fur, decreased activity, and eyes closed. Upon removal from the chamber, all animals exhibited wet and matted fur. All animals recovered by the first day post-exposure, with the exception of one

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

Test material information

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: During exposure, observed abnormalities included wet/matted fur, decreased activity, and eyes closed. Upon removal from the chamber, all animals exhibited wet and matted fur. All animals recovered by the first day post-exposure, with the exception of one

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).