Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
25 Jan - 16 Feb 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
1981
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
Version / remarks:
Commission Directive 92/69/EEC
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
THE DEPARTMENT OF HEALTH OF THE GOVERNMENT OF THE UNITED KINGDOM, UK GLP Monitoring Authority
Test type:
traditional method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Remarks:
Crl:CD® (SO) IGS BR
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River (UK) Ltd, Margate, Kent, UK
- Females nulliparous and non-pregnant: yes
- Age at study initiation: approx. 8 - 12 weeks
- Weight at study initiation: 200 - 350 g
- Fasting period: only during exposure period
- Housing: groups of up to five by sex in solid-floor polypropylene cages with stainless steel lids, furnished with softwood flakes and provided with environmental enrichment items: wooden chew blocks and cardboard "fun tunnels"
- Diet: free access to food (EU Rodent Diet 5LF2, BCM IPS Limited, London, UK)
- Water: free access to mains drinking water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 55 ± 15
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
1.67 µm
Geometric standard deviation (GSD):
9.47
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: cylindrical exposure chamber, the chamber was maintained under negative pressure.
- Exposure chamber volume: approx. 30 litres (dimensions: 28 cm diameter x 50 cm high)
- Method of holding animals in test chamber: each rat was individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber and sealed by means of a rubber 'O' ring.
- Source and rate of air: oil free compressor, air passed through a water trap and respiratory quality filters before entering the SAG 410
- Flow rate: 60 L/min (120 air changes/h)
- System of generating particulates/aerosols: SAG 410 Solid Aerosol Generator (TOPAS GmbH, Dresden, Germany)
- Method of particle size determination: Marple Personal Cascade Impactor (Westech IS Ltd, Beds., UK) consisting of six calibrated impactor stages (9.6, 6.6, 3.5, 1.8, 0.87 and 0.33 µm cut points) with stainless steel collection substrates and a back up glass fibre filter, housed in an aluminium sampler.
- Treatment of exhaust air: the extract from the exposure chamber passed through a 'scrubber' trap and was connected with a high efficiency filter to a metered exhaust system.
- Temperature in air chamber during exposure [°C]: 24 - 25
- Humidity in air chamber during exposure [%]: 29 - 32
- Oxygen concentration in air chamber during exposure [%]: 20.6 - 20.7

TEST ATMOSPHERE
- Brief description of analytical method used: The actual chamber concentration was measured at regular intervals during the exposure period. The gravimetric method used glass fibre filters (Gelman type A/E 25 mm) placed in a filter holder. The holder was temporarily sealed in a vacant port in the exposure chamber in the animals' breathing zone and a suitable, known volume of exposure chamber air was drawn through the filter using a vacuum pump. Each filter was weighed before and after sampling in order to calculate the weight of collected test material. The difference in the two weights, divided by the volume of atmosphere sampled, gave the actual chamber concentration. The nominal chamber concentration was calculated by dividing the mass of test material used by the total volume of air passed through the chamber.
- Samples taken from breathing zone: yes
- Mean maximm attainable atmosphere concentration: 1.87 mg/L
- MMAD (Mass median aerodynamic diameter [µm]): 1.67
- Inhalable fraction (% < 4 µm): 65.2
- GSD (Geometric st. dev.): 9.47
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
nominal: 5.1 mg/L
maximum attainable concentration: 1.87 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 and weighing: Observation for clinical signs were performed hourly during exposure, immediately at the end of exposure, 1 h after termination of exposure and subsequently daily for 14 days; bodyweights were recorded prior to treatment, on the day of exposure and on Days 7 and 14 or at death.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, other: The respiratory tract was subjected to a detailed macroscopic examination for signs of irritancy or local toxicity. The lungs, trachea and larynx from each animal were retained in buffered formalin prior to sections being prepared.

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 1.87 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: mean maximum attainable atmosphere concentration
Mortality:
One male (1/5) and no female (0/5) rat died at the maximum attainable concentration of 1.87 mg/L. The male was found dead at 223 min during the 4 h exposure period.
Clinical signs:
other: Common abnormalities noted during the study included increased respiratory rate, laboured respiration, noisy respiration, hunched posture, pilo-erection, fur staining by the test material and wet fur. There were isolated instances of decreased respiratory
Body weight:
One male animal showed a significant weight loss during Week 1 but recovered to show normal bodyweight development during Week 2. Normal bodyweight development was noted for all other surviving animals during the study.
Gross pathology:
Abnormally dark lungs and pale patches on the lungs were noted in all animals that survived until Day 14. The animal that died during the course of the study showed abnormally dark lungs with dark patches.

Any other information on results incl. tables

 

Table 5: Individual bodyweights

Mean achieved atmosphere concentration [mg/L air]

Animal number and sex

Bodyweight [g] on Day

Increment [g] during week

0

7

14

At death

1

2

1.87

1 Male

301

324

356

 

23

32

2 Male

321

251

331

 

-70

80

3 Male

297

312

346

 

15

34

4 Male

304

320

369

 

16

49

5 Male

325

-

-

316

-

-

6 Female

263

267

273

 

4

6

7 Female

233

253

258

 

20

5

8 Female

217

219

232

 

2

13

9 Female

242

266

275

 

24

9

10 Female

231

254

252

 

23

-2

 

Applicant's summary and conclusion

Interpretation of results:
other: CLP/EU GHS criteria not met, no classification required according to Regulation (EC) No. 1272/2008.
Conclusions:
Only one death occurred in a group of ten rats exposed to a mean maximum attainable atmosphere concentration of 1.87 mg/L air for 4 h. The acute inhalation median lethal concentration (LC50, 4 h) of the test item in the Sprague-Dawley Crl:CD® (SD) IGS BR strain rat was, therefore, determined to be > 1.87 mg/L air.