Butyric acid

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions: 3 animals per sex; observation period 7 days;

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Reference 2

Reference Type:

other company data

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

: 3 animals per sex; short observation period

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Butyric acid

EC Number:

203-532-3

EC Name:

Butyric acid

Cas Number:

107-92-6

Molecular formula:

C4H8O2

IUPAC Name:

butyric acid

Details on test material:

- Analytical purity: 99.5 %

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc.
- Age at study initiation: males: 9 weeks; females: 10 weeks
- Weight at study initiation: males: 291 - 295 g; females: 198 - 200 g
- Housing: individually in suspended, stainless steel, wire mesh cages
- Diet: standard pellets (Purina Rodent Laboratory Chow), ad libidum
- Water: ad libitum
- Acclimation period: 16 days


ENVIRONMENTAL CONDITIONS
- Temperature: 67 -76 ° F
- Humidity (%): 40 - 70
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Plexiglas chamber with glass front
- Exposure chamber volume: 100 liter
- Method of holding animals in test chamber: whole body exposure
- Source and rate of air: air flow rate was 20 liters per minutes, which provides a complete air change every 5 min.
- System of generating vapor: compressed air was directed through a wash bottle filled with 60 mL liquid test material, and further diluted with additional air
- Particle size measurement: yes, using a TSI Aerodynamic Particle Size analyzer
- Temperature: 24 °C; humidity: 36 - 39 %

TEST ATMOSPHERE
- Brief description of analytical method used: absorbance of airsamples was examined in a MIRAM 1A Ambient Air analyzer, using a calibration curve in the range 0-7 mg/l
- Samples taken from breathing zone: yes, hourly during exposure

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5.1 mg/L

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 7 days
- Frequency of observations and weighing: Animals were observed as a group every 15 min. during the first hour of exposure and afterwards hourly. Individually the animals were observed upon removal of the chamber, than hourly for two hours and afterwards daily; viability was assessed twice daily. Weighing: prior to exposure and on day 8
- Necropsy of survivors performed: no
- Other examinations performed: clinical signs, body weight

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC0

Effect level:

5.1 mg/L air

Exp. duration:

4 h

Mortality:

No mortality was observed during the exposure and the 7 day post-exposure period.

Clinical signs:

other: Respiratory irritation, lacrimation, closed eyes and decreased activity were noted during the exposure, but the animals recovered rapidly during the 2-hour Post-Exposure Period, and showed virtually no signs during the 7-day Post Exposure Period.

Body weight:

Most animals were in excess of their pre-exposure body weight by end of the study.

Gross pathology:

no post-mortem examination

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Butyric acid was relatively nontoxic, because all rats exposed for 4 hours to 5.1 mg/L survived with moderate clinical signs

Executive summary:

All 6 rats receiving a single four-hour exposure to 5.1 mg/L of butyric acid as a vapor survived the exposure and the 7 day observation period. While moderate signs of irritation were noted during the exposure, the animals recovered quickly and showed no adverse effects on body weight or clinical signs. Therefore, the LC0 was 5.1 mg/L (LC50 > 5 mg/L) in this study (Biodynamics, 1989).