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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to Guideline study with acceptable restrictions (mostly due to limited documentation in times before GLP)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report Date:
1987

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
GLP compliance:
no
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): N-ethylpiperidine
- Physical state: Liquid/colorless
- Analytical purity: > 99%
- Storage condition of test material: Room temperature

Test animals

Species:
rat
Strain:
other: Wistar/Chbb:THOM
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Dr. K. Thomae GmbH, Biberach, Germany
- Age at study initiation: 8 - 9 weeks
- Mean body weight at study initiation: males: 259 ± 11.03 g and females 174 ± 11.7 g.
- Housing: groups of five in wire cages, type DIII, of Becker
- Diet: KLIBA laboratory diet rat/mouse A 343 10-mm pellets, supplied by Klingentalmuehle AG, Kaiseraugst, Switzerland, ad libitum
- Water: drinking water, ad libitum

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

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Whole-body inhalation system; groups of 2 animals were placed in wire cages which were located in a glass-steel inhalation chamber
- Exposure chamber volume: ca. 200 L
- Method of conditioning air: The supply air was conditioned via central air conditioning in such a way that there was a temperature of 19-25°C in the exposure apparatus. There were no deviations from these specifications which might have had any adverse effect on the results of the study.
- System of generating particulates/aerosols: A mixture of vapour and air was generated by means of a continuous infusion pump INFU 362 (INDIGEL/Switzerland) and a glass evaporator with thermostat (BASF). By means of a metering pump, the test substance was supplied to an evaporator heated to 50°C for each test group. The vapours that were formed were mixed with a flow of fresh air and passed into the inhalation chamber.
- 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 there was a pressure slightly below the atmospheric pressure (negative pressure). This ensured that there was no contamination of the laboratory due to possible leakage from the inhalation chambers.
- Temperature, humidity, pressure in air chamber: 19-25°C

TEST ATMOSPHERE
- Brief description of analytical method used:
• The nominal concentration was determined from the consumption of test substance and the air flow.
- Sampling was performed using 2 absorption vessels connected in series and a downstream fritted glass flask. The fritted glass flask was used to check the sorption effectiveness for all samples of a test group and was analyzed separately. Thereby a sampling station with gas meter, impulse counter and automatic pump switch was used.
Sorption solvent: Dimethylformamide (DMF); Sampling velocity: 1.25 m/s; Sampling amount: 5L-10L; Sampling site: Immediately adjacent to the animal noses; Sampling probe diameter: 4 mm; Sampling frequency: 1 sample hourly per concentration group
• Analytical method of determination: A gas chromatographical method was used for the quantitative determination of the vapour concentration.
The samples were taken up in about 45 mL DMF (sorption solvent) and topped up to 50 mL after addition of 1 mL of internal standard solution.
- Gas chromatographical analysis: Equipment: GC HP 5840 A (Hewlett Packard);
- Calibration: A calibration curve was prepared with the test substance in the solvent specified. The curve was calculated with a Hewlett Packard Computer Program SD 03A (curve adjustment: linear regression).
- Calculation of the concentration: The concentrations in mg/L were calculated from the amounts determined analytically and the sample volumes of the inhalation atmosphere.


Analytical verification of test atmosphere concentrations:
yes
Remarks:
gas chromatographical method
Duration of exposure:
4 h
Concentrations:
Nominal concentration [mg/L]: Group 1: 8.24; group 2: 3.43; group 3: 2.64; group 4: 2.20
Analytical concentration [mg/L]: Group 1: 6.84; group 2: 2.82; group 3: 2.04; group 4: 1.88
No. of animals per sex per dose:
10
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The body weight of the animals was checked before the beginning of the test, after 7 days and at the end of the observation period. A check for mortalities was made daily.
- Necropsy of survivors performed: yes, at the end of the 14-day observation period, the surviving animals were sacrificed with CO2 and were subjected to a gross-pathological examination like all other animals which had died before.
- Other examinations performed: Clinical findings were generally recorded several times during exposure and at least once each workday during the post-exposure observation period.
Statistics:
The statistical evaluation of the concentration/effect relationship was carried out based on a probit analysis of D.J. Finney (Finney, D.J.: Probit Analysis 1971, pp 1-150. Published by the Syndics of the Cambridge University Press, Bentley House, 200 Euston Road, London N.W. 1).

Results and discussion

Effect levelsopen allclose all
Sex:
male/female
Dose descriptor:
LC50
Effect level:
2.42 mg/L air (analytical)
Based on:
test mat.
95% CL:
2.26 - 2.64
Exp. duration:
4 h
Sex:
male
Dose descriptor:
LC50
Effect level:
2.59 mg/L air (analytical)
Based on:
test mat.
95% CL:
2.33 - 3.03
Exp. duration:
4 h
Sex:
female
Dose descriptor:
LC50
Effect level:
2.26 mg/L air (analytical)
Based on:
test mat.
95% CL:
2.07 - 2.59
Exp. duration:
4 h
Mortality:
1.88 mg/L: no deaths occured;
2.04 mg/L: total at the end of the study: 5/20; 1/10 males and 4/10 females within 24 hours
2.82mg/L: total at the end of the study: 16/20; 7/10 males and 9/10 females within 24 hours
6.84 mg/L: total at the end of the study: 20/20; 10/10 males and 10/10 females within 24 hours
Clinical signs:
During exposure:
All test groups: restless behavior, lid closure, reddish discharge from the noses and anaemic aspect; in some animals tremors and convulsions.
Additionally, the animals of test groups (1) 6.84 mg/L, (2) 2.82 mg/L, and (3) 2.04 mg/L showed: wiping of the snouts; intermittent and irregular respiration; upright respiratory posture in some animals; salivation; lateral position in some cases.
The animals of test group 1 (6.84 mg/L) additionally showed: gasping; abdominal position; fur in the anogenital region reddish and smeared; tonus with stretching before death.

After exposure:
All test groups: margins of the noses reddish and encrusted (evidence of blood positive); slight tremor in some animals.
The animals of test group 2 (2.82 mg/L) additionally showed: slightly ruffled fur; anaemic aspect.
The animals of test group 3 (2.04 mg/L ) additionally showed: occasionally convulsions; ruffled fur; slight breathing sounds on day 3 after exposure.
The animals of test group 4 (1.88 mg/L) additionally showed: intermittent respiration in some animals.

No abnormalities were detectable in animals of the test group 2 (2.82 mg/L) from the 5th day of observation, in those of test group 3 (2.04 mg/L ) from the 7th day of observation and those of test group 4 (1.88 mg/L) from the 2nd day of the observation period.
Body weight:
Mean body weight:
Test Group (1): 6.84 mg/L: at study start: males: 259 g, females: 174 g
Test Group (2): 2.82 mg/L: at study start: males: 264 g, females: 185 g; after 7 days: males: 273 g, females: 192 g; after 14 days: males: 303 g, females: 202 g
Test Group (3): 2.04 mg/L: at study start: males: 254 g, females: 163 g; after 7 days: males: 281 g, females: 180 g; after 14 days: males: 306 g, females: 194 g
Test Group (4): 1.88 mg/L: at study start: males: 259 g, females: 175 g; after 7 days: males: 298 g, females: 192 g; after 14 days: males: 335 g, females: 201 g

The body weight gain of the males (test groups 2 and 3) and females (test group 2) was slightly retarded as compared with a historical control group during the first week of the observation period, but returned to normal body weight gain in the second week of the observation period.

The body weight gain of the males (test group 4) and females (test group 3) was not impaired as compared with a historical control group throughout the observation period.

The body weight gain of the females of test group 4 was slightly retarded as compared with a historical control group during the second week of the observation period; the biological relevance is questionable since there was no concentration-dependent effect as compared with the body weight gain of the females of test group 3.
Gross pathology:
Deceased animals (males and females): General passive hyperemia
Sacrificed animals (males and females): Organs: no abnormalities detected

Any other information on results incl. tables

Table1 Acute oral toxicity.

 

Concentration

[mg/L]

Mortality

Clinical signs

 

N*

%

Time of death

N*

Duration

Males

 

 

 

 

 

1.88

0/10

0

-

10/10

day 2

2.04

1/10

10

3 hours

10/10

until death, day 4

2.82

7/10

70

1.5 – 4 hours

10/10

until death, day 5

6.84

10/10

100

1 – 2.5 hours

10/10

until death

Females

 

 

 

 

 

1.88

0/10

0

-

10/10

day 2

2.04

4/10

40

3.5 hours

10/10

until death, day 4

2.82

9/10

90

3.5 – 4 hours

10/10

until death, day 5

6.84

10/10

100

1 – 2.5 hours

10/10

until death

*N= Number of animals/ number of animals used

 

Table 2 Body weight.

 

Concentration

[mg/L]

Body weight (mean ± SD)

 

initial

7 days

14 days

Males

 

 

 

1.88

259± 16.1 (10)

298± 14.3 (10)

335± 18.5 (10)

2.04

254± 8.8 (10)

281± 7.5 (9)

306± 10.8 (9)

2.82

264± 9.1 (10)

273± 8.6 (3)

303± 15.0 (3)

6.84

259± 6.9 (10)

-

-

Historical group

245

283

315

Females

 

 

 

1.88

175± 13.2 (10)

192± 11.35 (10)

201± 15.5 (10)

2.04

163± 7.7 (10)

180± 12.3 (6)

194± 11.9 (6)

2.82

185± 6.2 (10)

192(1)

202 (1)

6.84

173± 5.9 (10)

-

-

Historical group

176

196

211

 

 

Applicant's summary and conclusion