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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 Jul 2014 to 29 Jul 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report date:
2014

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
Adopted: 7 September 2009
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1300 (Acute inhalation toxicity)
Version / remarks:
1998
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
Version / remarks:
2008
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
traditional method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
bis((1S,2R,6R,7S,8R)-11-(dichloromethylidene)-6-hydroxytricyclo[6.2.1.0²,⁷]undecan-3-one)
EC Number:
941-628-3
Cas Number:
1263184-87-7
Molecular formula:
C12H14Cl2O2
IUPAC Name:
bis((1S,2R,6R,7S,8R)-11-(dichloromethylidene)-6-hydroxytricyclo[6.2.1.0²,⁷]undecan-3-one)
Test material form:
solid

Test animals

Species:
rat
Strain:
Wistar
Remarks:
CRL
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Age at study initiation: 11-12 weeks
- Weight at study initiation: 401-535 g (males); 246-312 g (females)
- Fasting period before study: No
- Housing: 5 per sex in Type III solid floor cages with stainless steel mesh lids. Rodents were housed with deep wood sawdust bedding to allow digging and other normal rodent activities. Lignocel Bedding for Laboratory Animals was available to animals during the study.
- Diet: Autoclavable Complete Feed for Rats and Mice – Breeding and Maintenance, ad libitum, except during exposure.
- Water: Tap water ad libitum, except during exposure.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.2-26.5
- Humidity (%): 30-72
- Air changes (per hr): 15-20
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES:
15 Jul 2014 to 29 Jul 2014

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
3.01 µm
Geometric standard deviation (GSD):
2.27
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Rodent Exposure System
- Exposure chamber volume: 3.85 L (inner plenum)
- Method of holding animals in test chamber: The animals were held in polycarbonate restraint tubes located around the chamber which allowed only the animal’s nares to enter the exposure port.
- Rate of air flow in (inner plenum): 15.0 L/min
- Rate of air flow out (inner plenum): 29.9 L/min
- System of generating particulates/aerosols: The test item was aerosolised using two Dust Feed Systems located at the top of the exposure chamber. Compressed air was supplied by means of an oil-free compressor and passed through a suitable filter system prior to introduction to the dust generator.
- Method of particle size determination: The particle size of the test atmosphere was determined three times during the exposure period using a 7-stage impactor of Mercer style.
- Temperature, humidity, oxygen concentration in air chamber: 23.6°C, humidity not recorded, oxygen concentration 20.6%.

TEST ATMOSPHERE
- Brief description of analytical method used: A known volume of test atmosphere was passed through weighed GF10 glass fibre filters. The difference in the pre- and post-sampling weights, divided by the volume of atmosphere sampled, was equal to the actual achieved test atmosphere concentration.
The nominal concentration was calculated by dividing the mass of test material disseminated into the chamber by the total volume of air that went through the chamber during the same period.
- Samples taken from breathing zone: Yes

TEST ATMOSPHERE
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 3.01 µm / 2.27
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
Target concentration 5 mg/L. Actual avarage concentration 5.05 ± 0.12 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: Observed once per hour during exposure, as soon as possible following removal from restrains at the end of exposure, 1 hour after exposure and twice daily for 14 days thereafter. Body weights were recorded prior to treatment on the day of exposure (Day 0) and on Days 1, 3, 7 and 14.
- Necropsy of survivors performed: Yes. After examination of the external appearance, the thoracic and abdominal cavities were opened and the appearance of the tissues and organs were observed. Any gross macroscopic changes were recorded. Special attention was given to the respiratory tract for macroscopic signs of irritancy or local toxicity.
Statistics:
Not applicable (limit test, no mortalities).

Results and discussion

Preliminary study:
Sighting Exposure:
The mean achieved atmosphere concentration was 5.03 mg/L. The MMAD (Mean Mass Aerodynamic Diameter) was 3.01 μm ± 2.31 (GSD [Geometric Standard Deviation]). There was no mortality.
Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5.05 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
not determinable due to absence of adverse toxic effects
Mortality:
There was no mortality.
Clinical signs:
other: Wet fur and/or fur staining were recorded in animals on the day of exposure and in some occasions on the day following exposure. These observations were considered to be related to the restraint and exposure procedures and, in isolation, were considered n
Body weight:
Normal body weight gain was noted for all exposed animals during the observation period, with the exception of one female where slight body weight loss was observed during period Day 1-3.
Gross pathology:
No treatment-related findings.

Any other information on results incl. tables

Table 1: Summary of acute study test atmosphere characteristics

Achieved concentration

5.05 ± 0.12 mg/L (n=17)

Nominal concentration

9.37.mg/L

Particle size MMAD; GSD

3.01 µm; 2.27 (n=3)

Inhalable fraction (% <4 µm)

63.6

 

Cumulative Mass (%)

Particles<0.55µm

2.95 (n=3)

Particles0.55-0.96µm

8.06 (n=3)

Particles0.96-1.55µm

15.70 (n=3)

Particles1.55-2.11µm

26.29 (n=3)

Particles2.11-3.56µm

62.28 (n=3)

Particles3.56–6.66µm

85.83 (n=3)

Particles6.66-10.55µm

93.84 (n=3)

Particles>10.55µm

100.00

Flow rate in (Inner plenum) (whole system)

15.0 L/min

Flow rate out (outer cylinder)

29.9 L/min

Theoretical chamber equilibrium time (T99)

1 minute

Actual equilibrium time allowed

11 minutes

Temperature

23.6°C (maximum/minimum 22.5/24.0°C)

Humidity

Not measured

Oxygen content

20.6% (maximum/minimum 20.3/20.8%)

 

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the experimental conditions of this study, no deaths occurred in a group of 10 rats exposed to a mean achieved concentration of 5.05 mg/L for 4 hours. The acute inhalation median lethal concentration (LC50) in CRL: (WI) Wistar strain rats is, therefore, considered to be greater than 5.05 mg/L.
Executive summary:

In this GLP compliant, OECD 403 acute inhalation toxicity study, 5 male and 5 female CRL: (WI) Wistar strain rats, were exposed to a mean achieved concentration of 5.05 mg/L test substance for 4 hours using a nose-only exposure system, followed by a 14 day observation period. The day of exposure was designated Day 0. Aerosol concentrations were measured gravimetrically. The particle size distribution of the test aerosol was determined regularly during the exposure period. Clinical observations and body weights were recorded throughout the study and at the end of the scheduled period the animals were euthanised and subjected to a gross examination post mortem.

The mean achieved atmosphere concentration was 5.05 mg/L. The MMAD (Mean Mass Aerodynamic Diameter) was 3.01 μm ± 2.27 (GSD [Geometric Standard Deviation]). There was no mortality. Wet fur and/or fur staining were recorded in animals on the day of exposure and in some occasions on the day following exposure. These observations were considered to be related to the restraint and exposure procedures and, in isolation, were considered not to be of toxicological relevance. Only slight to moderate laboured respiration was noted for the exposed animals on the day of exposure. No clinical signs were noted from Day 1 until the end of the observation period. Normal body weight gain was noted for all exposed animals during the observation period, with the exception of one female where slight body weight loss was observed during period Day 1-3. There were no treatment-related changes at gross examination post mortem.

Under the experimental conditions of this study, no deaths occurred in a group of 10 rats exposed to a mean achieved concentration of 5.05 mg/L for 4 hours. The acute inhalation median lethal concentration (LC50) in CRL: (WI) Wistar strain rats is, therefore, considered to be greater than 5.05 mg/L.