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Acute Toxicity: inhalation

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acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
(adopted 1981)
GLP compliance:
BASF AG, Department of Toxicology
Test type:
standard acute method
Limit test:

Test material

Details on test material:
- Name of test material (as cited in study report): Di-2-ethylhexylamin
- Physical state: liquid / colourless
- Analytical purity: 99.6 %
- Lot/batch No.: GLP 89/722
- Stability under test conditions: Stability was ensured for at least the study period.
- Storage condition of test material: was stored at room temperature, without CO2, under N2

Test animals

Details on test animals and environmental conditions:
- Strain as named in the report: SPF Wistar/Chbb: THOM
- Source: Dr. K. Thomae GmbH, Biberach, FRG
- Age at study initiation: approximately 8-9 weeks
- Weight at study initiation: males: 260 ± 12.1 g (mean), female: 181 ± 5.7 g (mean)
- Housing: in groups of five, in cages type DK III of Becker
- Diet: KLIBA rat/mouse laboratory diet 24-343-4, 10 mm pellets, Klingenthalmuehle AG, Kaiseraugst, Switzerland, ad libitum
- Water: ad libitum (during the post-exposure observation period)

- Temperature (°C): 20-24 °C
- Humidity (%): 30-70%
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose/head only
other: unchanged (no vehicle)
Details on inhalation exposure:
- Exposure apparatus: Head-nose inhalation system INA 20 (glass-steel construction, BASF AG)
- Exposure chamber volume: 55 L
- Method of holding animals in test chamber: The animals were restrained in tubes and their snouts projected into the inhalation chamber.
- Source and rate of air: 1500 L/h
- System of generating particulates/aerosols: A liquid aerosol was generated by means of a continuous infusion pump INFU 362 (INDIGEL/Switzerland) and a two-component atomizer Mod. 970 (Schlick). By means of compressed air the aerosol was generated, which was passed into the inhalation system.
- Method of particle size determination: gas chromatography
- Treatment of exhaust air: By means of an exhaust air system the pressure ratios in the inhalation system were adjusted in such a way that the amount of exhaust air was about 10 % lower (excess pressure). This ensured that the mixture of test substance and air was not diluted with laboratory air in the breathing zones of the animals.
- Temperature in air chamber: 19 - 25 °C

- Brief description of analytical method used: gas chromatography (from the analytically determined mass values and the sample volumes of the inhalation atmosphere the concentrations were calculated in mg/L).
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:
gas chromatography
Duration of exposure:
4 h
- analytical: 0.28 mg/L (test group 1), 0.53 mg/L (test group 2), 0.84 mg/L (test group 3), 1.28 mg/L (test group 4), 2.85 mg/L (test group 5)
- nominal: 0.54 mg/L, 0.97 mg/L, 1.61 mg/L, 3.11 mg/L, 5.37 mg/L
No. of animals per sex per dose:
Control animals:
other: historical controls
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations: at least once on each workday
- Frequency of weighing: Before the beginning of the test, after 7 days (test groups 1, 2, 4 and 5), after 8 days (test group 3) and at the end of the observation period.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight
The statistical evaluation of the dose-response relationship was carried out using FORTRAN program AKPROZ.
The calculation of the particle size distribution was carried out in the Department of Toxicology of BASF AG on the basis of mathematical methods
for evaluating particle measurements (DIN 66141: Darstellung von Korngroeßenverteilungen, DIN 66161: Partikelgroeßenanalyse).

Results and discussion

Effect levels
Key result
Dose descriptor:
Effect level:
0.91 mg/L air
Based on:
test mat.
95% CL:
> 0.73 - < 1.19
Exp. duration:
4 h
Remarks on result:
other: Systemic toxicity (including mortality) and local irritation observed; see descriptions below for details
0.28 mg/L: no mortalities occurred.
0.53 mg/L: 1 male died on day 2.
0.84 mg/L: 2 males and 1 female died on day 2 and a further female died until day 7.
1.28 mg/L: 2 males and all 5 females died on day 0 and a further male died on day 2.
2.86 mg/L: all animals died within 3 h of exposure.
Clinical signs:
other: During exposure: 0.28 mg/L: initially escape attempts; irregular respiration until the end of exposure. 0.53 mg/L: initially escape attempts and accelerated respiration; whooping respiration; intermittent respiration and decreased pain reflex until the e
Body weight:
The body weight gain of the female rats in the test group 1, compared with a historical control collective, was not affected by the substance over the total observation period.
The body weight gain of the male rats in the test groups 1, 2, 3, compared with a historical control collective, was slightly retarded in the first week of the observation period and adjusted to normal in the second week of the observation period.
The body weight gain of the female rats in the test group 2, compared with a historical control collective, was slightly retarded in the second week of the observation period.
The body weight gain of the female rats in the test group 3, compared with a historical control collective, was reduced over the total observation period.
The body weight gain of the male animals in the test group 4, compared with a historical control collective, was reduced in the first week of the observation period and adjusted to normal in the second week of the observation period. The animals did not, however, reach the body weight which they had before exposure.
Gross pathology:
Animals that died spontaneously:
All groups: general congestion.
0.53, 0.84, 1.28 mg/L: lungs: intensified focal hyperemia, additional moderate emphysema.
1.28 mg/L: liver: slightly marked grey brown lobules.
2.85 mg/L: lungs: intensified hyperemia with edema.

Sacrificed animal: no pathologic findings noted.

Any other information on results incl. tables


 Dose (mg/L)  Gender  Day 0  Day 1  Day 2  Day 7  Day 14
 0.28  male  0/5  0/5 0/5  0/5  0/5 
 0.28  female  0/5  0/5 0/5  0/5  0/5 
 0.53  male  0/5  0/5 1/5 1/5 1/5
 0.53  female  0/5  0/5 0/5 0/5 0/5
 0.84  male  0/5 0/5  2/5 2/5 2/5
 0.84 female  0/5  0/5 1/5 2/5 2/5
 1.28 male   2/5  2/5 3/5 3/5 3/5 
 1.28  female  5/5 5/5 5/5  5/5  5/5 
 2.86  male  5/5  5/5 5/5  5/5  5/5 
 2.86  female  5/5 5/5 5/5  5/5  5/5 

Body weight:

 Mean body weight (in g)   male        female     
   0 days  7 days  14 days  0 days  7 days  14 days
 0.28 mg/L 269 281 324  183  196  207 
0.53 mg/L 265  274  314  181  194  201 
 0.84 mg/L 262  263  314  182  176  175 
 1.28 mg/L 257  194  226  179 
2.86 mg/L 251   - 179
 historical control 248  286  318  177  196  211 

"-": all animals dead.

Particle size analysis:

Test group MMAD 50% [µm] GSD Respirable fraction [%]
1 1.6 3.3 95
2 1.5 3.4 95
3 1.7 3.5 93
4 1.4 3.8 94
5 1.8 3.7 93

Applicant's summary and conclusion

Interpretation of results:
Category 3 based on GHS criteria
The study on acute inhalation toxicity of Di-2-ethylhexylamine as an aerosol in male and female Wistar rats resulted in a LC 50 value for both sexes of 0.91 mg/L after an exposure period of 4 hours and an observation period of 14 days. The particle size analysis revealed that the amount of respirable fraction was very high. A classification according to the CLP Regulation (EC) No. 1272/2008 (EU-GHS: Cat. 3) is required.