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Acute Toxicity: inhalation

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acute toxicity: inhalation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Study period:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-study according to OECD guideline 403.

Data source

Reference Type:
study report
Report date:

Materials and methods

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

Test material

Constituent 1
Reference substance name:
isopentanoic acid (mixture of valeric acid and 2-methylbutyric acid)
isopentanoic acid (mixture of valeric acid and 2-methylbutyric acid)
Details on test material:
A 1-liter container (gross weight = 1385.2 g) of Isopentanoic Acid (Mixed Isomers), Identification No. TS-700208, CAS No. not available for this
mixture, was received on February 14, 1994, from OCC, Texas City, TX, and assigned BRRC Sample No. 57-35. The test substance was a water-white liquid. It was stored at room temperature. The test substance was 99.4% active ingredient (total C5 acid) according to the Certificate of Analysis

Test animals

Details on test animals or test system and environmental conditions:
- Source: Harlan Sprague Dawley, Inc. (Indianapolis, IN).
- Age at study initiation:
- Weight at study initiation: 220 to 243 g for males and 222 to 248 g for females.
- Fasting period before study: yes
- Housing:The animals were separated by sex and group housed (up to 5/cage) in stainless steel, wire mesh cages (approximately 30.5 x 31.0 x 1B.0 cm in one room and 23.5 x 40 x 18 cm in another room.). DACB® (Deotized Animal Cage Board Shepherd Specialty Papers, Inc.) was placed under each cage and changed regularly.
- Diet: Pelleted, certified AGWAY® PROLAB® Animal Diet Rat, Mouse, Hamster 3000 (Agway Inc.) was available ad libitum. For the peroral test, the feed was removed the day before dose administration. After dosing, feed was again made available ad libitum.
- Wate: Tap water (Municipal Authority of Westmoreland County, Greensburg, PA) was available ad libitum except during dosing and was delivered by an automatic watering system with demand control valves mounted on each rack.
- Acclimation period: 5 days

- Temperature (°C): 66-77°F
- Humidity (%): 40-70%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): fluorescent lighting for a 12-hour photoperiod (approximately 0500 to 1700 hours for the light phase).

IN-LIFE DATES: From: April 27, 1994 to May 11, 1994

Administration / exposure

Route of administration:
Type of inhalation exposure:
whole body
other: unchanged (no vehicle)
Details on inhalation exposure:
6-Hour Static Conditions at 24°C

A substantially saturated vapor was produced by enclosing 107.6 g of Isopentanoic Acid (Mixed lsomers) in a sealed 120-liter animal chamber for
approximately 16.5 hours under static conditions. In order to aid in the distribution of the vapor, a mixing fan periodically agitated the chamber
atmosphere. Oxygen was added as needed to the chamber in order to maintain a chamber oxygen content of approximately 20%. The average temperature and humidity in the chamber during the exposure period were approximately 24ºC and 88%, respectively. No analysis was made of the chamber atmosphere for the concentration of the test substance.
Analytical verification of test atmosphere concentrations:
Duration of exposure:
16.5 h
Saturated atmosphere
No. of animals per sex per dose:
A total of 5 male and 5 female rats were used in the inhalation toxiclty test
Control animals:
Details on study design:
Five male and 5 female rats were placed into the chamber and sealed inside for the 6-hour exposure period. Dosed rats were observed frequently during the exposure for signs of toxicity and twice a day thereafter (except on weekends or holidays when they were examined for death alone). Weights were recorded on the day of dosing and at 7 and 14 days after dosing. At 14 days, all animals were anesthetized using methoxyflurane and killed by exsanguination following severance of the brachial vessels. All rats were then necropcied.
Any LD50 value, along with its 95% confidence limits, will be calculated by the moving average method (Thompson, 1947). Estimates of the slope will use the method of Weil (1983).

Results and discussion

Effect levels
Dose descriptor:
Effect level:
other: saturated vapor
Exp. duration:
6 h
Remarks on result:
other: No deaths
Gross pathology:
No gross lesions were apparent for any animal at necropsy.

Any other information on results incl. tables

Exposure to a statically-generated, substantially saturated vapor did not produce deaths in any of 5 male or 5 female rats during or following the 6-hour test. There were no signs of toxicity observed in any animal. A "goaty" odor (resulting from the lingering effect of the chemical on the fur) was apparent following exposure. No odor was detectable within 1 day. All rats exhibited a weight gain during the 14-day observation period. No gross lesions were apparent for any animal at necropsy.

Applicant's summary and conclusion

Interpretation of results:
not classified
Migrated information Criteria used for interpretation of results: EU
A single static inhalation exposure(6 hours) of saturated vapor to rats produced no deaths or clinical signs of toxicity.