Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1989-11-23 to 1989-12-27
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report Date:
1990

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
12 May 1981
Deviations:
no
GLP compliance:
no
Test type:
traditional method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 8-9 weeks
- Weight at study initiation: male: 267 ± 19.1 g; females: 190 ± 8.2 g
- Housing: groups of five animals in cages type D III of Becker, without beedding
- Diet (e.g. ad libitum): ad libitum during the post exposure period, Kliba rat/mouse laboratory diet 24-343-4 10 mm pellets, Klingentalmühle AG, CH-4303 Kaiseraugst Switzerland
- Water (e.g. ad libitum): ad libitum

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

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose/head only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
> 1.8 - <= 3.1 µm
Geometric standard deviation (GSD):
>= 3 - <= 3.7
Remark on MMAD/GSD:
The MMAD and the GSD was calculated from the results of the particle size analysis which was performed for each test group.
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER
DESCRIPTION
- Exposure apparatus: Head-nose inhalation system INA 20 (glass-steel construction. BASF Aktiengesellschaft, volume V =55 L): the animals were restrained in tubes and their snouts projected into the inhalation chamber.
- 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: compressed air and dilution were set to: 1,500 [1/h]
- Method of conditioning air: The dilution air was conditioned via a central air-conditioning system
- System of generating particulates/aerosols: A dust aerosol was generated by means of an solid, particle generator [brush generator, Technical University of Karlsruhe/BASF] (test group 1) and a dosing-wheel dust generator (Gericke/BASF) (test groups 2, 3, 4).
- Method of particle size determination: At the beginning of the test in test group 1 or 30 min earliest after beginning of the test in test groups 2-4 one sample was taken for the particle size analysis. Before the sampling, the impactor was equipped with glass-fiber collecting discs and a backup particle filter. The impactor was connected to the pump and the test apparatus, and one sample (9-720L) was taken. The impactor was taken apart, and the collecting discs and the backup particle filter were weighed. The contents of the pre-impactor as well as the amounts of the material adsorbed on the walls of the impactor and in the sampling probe (wall losses) were also determined quantitatively.
- 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: 19-25 °C

TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric determination of the inhalation atmosphere concentration: The preweighed filter was placed into the filtration equipment, By means of a vacuum compressed air pump volume of the dust aerosol was drawn through the filter. The dust concentration in mg/L was calculated from the difference between the preweight of the filter and the weight of the filter after sampling, with reference to the sample volume of the inhalation atmosphere. The concentrations were corrected for the amount of the additive.
- Samples taken from breathing zone: yes

VEHICLE
- Composition of vehicle (if applicable):The test substance was mixed with 1%[w/w] Aerosil
- Justification of choice of vehicle: The vehicle was chosen in order to achieve a more uniform dust concentration in air.

Analytical verification of test atmosphere concentrations:
yes
Remarks:
Gravimetric determination of the inhalation atmosphere concentration
Duration of exposure:
4 h
Concentrations:
Nominal concentration: 0.016, 0.13, 0.52, 5.0 mg/L
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days for the test groups 2-4 and 16 days for the test group 1.
- Frequency of observations and weighing: Body weight was determined before the test, after 7 days and at the end of the observation period. Clinical findings were recorded several times during exposure and at least once on each workday in the observation period. Mortality was checked daily.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, gross necropsy
Statistics:
The statistical evaluation of the dose-response relationship was carried out using FORTRAN program AKPROZ. Depending on the data of the dose-relationship obtained by way of experiment, this program is used to estimate the LC50 or to perform a Probit analysis. Estimation of the LC50 will produce types LC50 greater, LC50 about, or LC50 smaller. If the reults are Type LC50 greater or LC50 smaller, an additional binominal test will be carried out, to verify these statements statistically, if necessary. The calculation of the particle size distribution was carried out on the basis of mathematical methods for evaluating particle measurements (DIN 66141: Darstellung von Korngrößenverteilungen, DIN 66161: Partikelgrößenanalyse)

Results and discussion

Effect levelsopen allclose all
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
ca. 0.09 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Sex:
male
Dose descriptor:
LC50
Effect level:
> 0.016 - < 0.13 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: The statistical reliability for the male rats is 95 %.
Sex:
female
Dose descriptor:
LC50
Effect level:
ca. 0.13 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
Test group 1: No deaths occurred until the end of the observation period.
Test group 2: 5 males and 2 females died on the day of exposure.
Test group 3: 3 males and 4 females died on the day of exposure and 2 males and 1 female died on observation day 1.
Test group 4: 5 males and 5 females died on the day of exposure.
Clinical signs:
Test group 1: All animals showed accelerated respiration during the exposure time. From day 1 after exposure until the end of the 16 days observation period no further clinical signs were reported.
Test group 2: During the exposure time and the first 2 observation days the surviving 3 animals exhibited respiratory problems and reddish nasal discharge, nose with reddish smear and crusts, ruffled fur or urine-contaminated fur. These signs were absent from day 3 until the end of the observation period.
Test group 3: All animals showed clinical signs like eyelid closure, restlessness and attempts to escape during the time of exposure. Most frequent were clinical signs like irregular, intermittent, accelerated, whooping or gasping respiration and respiratory sounds and reddish nasal discharge, nose with reddish smear and crusts, ruffled fur or urine-contaminated fur. These signs persisted until the first day after exposure when the surviving 3 animals died.
Test group 4: All animals showed clinical signs like eyelid closure, restlessness and attempts to escape during the time of exposure. Most frequently clinical signs like irregular, intermittent, accelerated, whooping or gasping respiration and respiratory sounds were observed. Within this group 4 animals died at 2h of exposure and the remaining 6 animals died at the end of the exposure time.
Test groups 2-4: All animals showed clinical signs like eyelid closure, restlessness and attempts to escape during the time of exposure. Most frequent in all treatment groups were clinical signs like irregular, intermittent, accelerated, whooping or gasping respiration and respiratory sounds.

Body weight:
The body weight gain of males and females of test group 1 was retarded, for males in observation week 1 and for females in observation week 2. However, the male animals in test group 1 regained body weight during the second week and was adjusted to normal. Body weight gain in test group 2 could only be detected in female rats and was not affected by the treatment as compared to a historical control collective. The body weights of test groups 3 and 4 were not recorded during the observation period due to premature death of the animals.
Gross pathology:
At the end of the obsevation period (14 days test groups 2, 3, 4; 16 days test group 1) the surviving animals were sacrificed with CO2 and were subjected to gross-pathological examination like all other animals which had died before.
Findings in animals that died spontaneously: Lungs: marked hyperemia with edema and/ or with emphysema; Thorax: hydrothorax in some animals. Findings in the sacrificed animals: None.

Any other information on results incl. tables

Table 1: concentration measurements

Sample No

Analytical concentration [mg/L]

Test group 1

13

0.018

14

0.017

15

0.016

16

0.014

Mean

0.0163

Mean corrected for 1% additive

0.0161

Mean (rounded)

0.016

Standard deviation of the mean

±0.0017

Nominal concentration

0.021

Test group 2

9

0.17

10

0.13

11

0.13

12

0.12

Mean

0.138

Mean corrected for 1% additive

0.134

Mean (rounded)

0.13

Standard deviation of the mean

±0.022

Nominal concentration

5.77

Test group 3

5

0.54

6

0.53

7

0.56

8

0.48

Mean

0.528

Mean corrected for 1% additive

0.518

Mean (rounded)

0.52

Standard deviation of the mean

±0.034

Nominal concentration

15.5

Test group 4

1

5.25

2

5.35

3

5.11

4

4.68

Mean

5.10

Mean corrected for 1% additive

5.049

Mean (rounded)

5.0

Standard deviation of the mean

±0.30

Nominal concentration

28.1

Applicant's summary and conclusion

Interpretation of results:
Category 2 based on GHS criteria
Conclusions:
In the present study conducted according to OECD guideline 403, GLP, 5 female and 5 male Wistar rats were exposed to 0.016, 0.13, 0.52, 5.0 mg/L of the test substance using a head-nose inhalation system for 4h. The animals were observed for further 14 days in test group 2-4 and for 16 days in test group 1. In test group 2, 3 and 4, three female, two male and 1 female and five male and five female animals died after exposure, respectively. In test group 3 all animals were dead at the end of observation day 1. The combined LC50 for male and female rats was estimated to be 0.09 mg/L air. Based on the study results, the test material fulfils the criteria for classification as acute toxicity by inhalation Category 2 in accordance with Regulation (EC) 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), and is thus considered to be fatal if inhaled.