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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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well-reported guideline study. No data on GLP compliance.

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)
Deviations:
no
GLP compliance:
not specified
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Purity: technical
- Storage: room temperature
- Physical state: solid (powder)
- Appearance: blue
- Stability: guaranteed for the duration of the study

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Further description: SPF/chbb: THOM
- Source: Dr. K. Thomae GmbH, D-7950 Biberach, FRG
- Age at study initiation: 8-9 weeks
- Weight at study initiation: 273 ± 6.4 g (male), 188 ± 6.2 g (female)
- Housing: 5 per DK III cages (Becker); without bedding
- Diet: ad libitum; KLIBA rat/mouse laboratory diet 24-343-4 10 mm pellets, Klingentalmuehle AG, CH-4303 Kaiseraugst, Switzerland. (Assaying for contamination indicated levels not expected to influence the study outcome)
- Water: ad libitum (Assaying for contamination indicated levels not expected to influence the study outcome)

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

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose/head only
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: INA 20 glass-steel construction, BASF AG
- Exposure chamber volume: ca. 55 L
- Method of holding animals in test chamber: animals were restrained in tubes and their snouts projected into the inhalation chamber
- System of generating particulates/aerosols: A dust aerosol was generated by means of a dosing-wheel dust generator (Before generation of aerosols, the test substance was desagglomerated with a mixer). The concentration was adjusted by varying the rotation of the metering disc.
- Method of particle size determination: An impactor equipped with glass-fiber collecting discs and a backup particle filter was connected to the pump and the test apparatus, and one sample (9 L) was taken. For analysis, the impactor was taken apart (30 minutes after test begin), and the collecting discs and the backup particle filter were weighed (Sartorius M3P and Mettler AE 240). 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.
- Temperature/humidity/ pressure in air chamber: 19 - 25°C/no data/To ensure that the mixture of test substance and air was not diluted with laboratory air in the breathing zones of the animals, the pressure ratios in the inhalation system were adjusted by means of an exhaust air system in such a way that the amount of exhaust air was about 10 lower (excess pressure).


TEST ATMOSPHERE
- Brief description of analytical method used: The preweighed filter was placed into the filtration equipment. By means of a vacuum compressed air pump a 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.
- Equipment: Mettler AE 24 0
- Samples taken from breathing zone: yes
- Frequency of sampling: 1 per hour
- Sampling amount/velocity: 2 L/1.25 m/s
- Filter: MN 85/90 Bf (d = 4.7 cm)
- Nominal concentration: calculated from the amount of substance consumed and the air flow

TEST ATMOSPHERE (if not tabulated)
- MMAD 50% (Mass median aerodynamic diameter 50%) / GSD (Geometric st. dev.): 1.9 µm/3.9
- Respirable dust aerosol fraction (reaching the alveolar region): 89%
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
- Nominal concentration: 110 mg/L
- Analytical concentration: 5.5 ± 0.246 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
- Frequency of observations for mortality: daily
- Frequency of observations for clinical signs of toxicity: several times during exposure, then at least once daily till termination; no observations were performed on days 3, 4, 10, 11 and 12 (holiday or weekend).
- Frequency of weighing: before start of study, on day 7, and at termination of the study
- Necropsy of survivors performed: yes
Statistics:
The statistical evaluation of the concentration/effect relationship was carried out on the basis of the binomial test (Witting, H.: Mathematische Statistik 1974, pp. 32 - 35) in accordance with tables of the BASF Computer Center. The calculation of the particle size distribution was carried out on the basis of mathematical methods for evaluating particle measurements (DIN 66141: Darstellung von Korngroeßenverteilungen, DIN 66161: Partikelgroeßenanalyse).

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5.5 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: Mortality (1/10) after 14 days.
Mortality:
3.5 hours after begin of exposure, 1 of 5 female animals was found dead. No mortality occurred in the male animals.
Clinical signs:
other: During exposure: - accelerated respiration, irregular respiration, intermittent respiration, eyelid closure, attempts to escape (see table 1 for further information). After exposure and during observation period: - accelerated respiration, intermittent
Body weight:
Body weight gain over the observation period was comparable to that of historical (air) controls. On day 7 post treatment, body weights were increased by 9.5 and 10% (compared to initial bodyweights) in female and male animals, respectively) versus 10 and 15% in historical controls. On day 14 post treatment, body weights were increased by 12 and 21% (compared to initial bodyweights, respectively) versus 19 and 28% in historical controls.
Gross pathology:
- Animal that died: general congestion, lung (atelectasis, cardiac lobe)
- Sacrificed animals: no pathological findings noted

Any other information on results incl. tables

Table 1: Clinical signs and findings: during exposure (number of animals eliciting symptom)

Time after begin of exposure

< 15 min

15 min

30 min

1 h

2h

3h

3.5 h

4h

Lethality (# of animals)

 -

 -

 -

 -

 -

 -

1

 -

Irregular respiration

 -

 -

4

6

 -

 -

 -

 -

Accelerated respiration

 -

 -

 -

4

10

10

9

4

Intermittent respiration

 -

 -

 -

 -

 -

 -

3

5

Closed eyelids

 -

10

10

10

10

10

10

9

Escape attempts

10

 -

 -

 -

 -

 -

 -

 

Applicant's summary and conclusion