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Administrative data

acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study performed under GLP. All relevant validity criteria were met.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)
GLP compliance:
yes (incl. QA statement)
inspected: July 2012; signature: November 2012
Test type:
acute toxic class method
Limit test:

Test material

Constituent 1
Chemical structure
Reference substance name:
Reaction mass of (3E)-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one and 4-(dodecylsulfanyl)-4-(2,6,6-trimethylcyclohex-1-en-1-yl)butan-2-one and 4-(dodecylsulfanyl)-4-(2,6,6-trimethylcyclohex-2-en-1-yl)butan-2-one
EC Number:
Molecular formula:
not applicable (reaction mass of constitutional isomers)
Reaction mass of (3E)-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one and 4-(dodecylsulfanyl)-4-(2,6,6-trimethylcyclohex-1-en-1-yl)butan-2-one and 4-(dodecylsulfanyl)-4-(2,6,6-trimethylcyclohex-2-en-1-yl)butan-2-one
Test material form:
gas under pressure: refrigerated liquefied gas
Details on test material:
- Physical state: liquid
- Storage condition of test material: Approximately 4°C in the dark under nitrogen.
- Other: Pale yellow

Test animals

Details on test animals or test system and environmental conditions:
- Source: Recognised supplier
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 200 - 350 g
- Fasting period before study: None.
- Housing: Housed in groups of up to three by sex in solid-floor polypropylene cages with stainless steel lids, furnished with softwood flakes provided with environmental enrichment items: wooden chew blocks and cardboard “fun tunnels”
- Diet (e.g. ad libitum): Certified diet from recognised supplier, provided ad libitum (except for exposure period period)
- Water (e.g. ad libitum): ad libitum (except for exposure period period)
- Acclimation period: At least 5 days

- Temperature (°C): 19 - 25
- Humidity (%): 30 - 70%
- Air changes (per hr): > 15 air changes per hour
- Photoperiod: 12 h light / 12 h dark

IN-LIFE DATES: From: To: 2013-05-13 to 2013-06-26

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Oxygen concentration (%) was monitored during the study
Details on inhalation exposure:
- Exposure apparatus: The test item was aerosolized using a glass concentric jet nebulizer located at the top of the exposure chamber. The nebulizer was connected to a plastic syringe attached to an infusion pump, which provided a continuous supply of test item under pressure, and to a metered compressed air supply.
- Exposure chamber volume: approximately 30 litres (dimensions: 28 cm diameter x 50 cm high)
- Method of holding animals in test chamber: Prior to the day of exposure each rat was acclimatized (for approximately 2 hours) to a tapered polycarbonate restraining tube. During the exposure period, 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. Only the nose of each animal was exposed to the test atmosphere.
- Source and rate of air: filtered air; chamber flow rate was maintained at 60 L/min providing 120 air changes per hour.
- Method of conditioning air: Compressed air was supplied by means of an oil free compressor and passed through a water trap and respiratory quality filters before it was introduced to the nebulizer.
- System of generating particulates/aerosols: glass concentric jet nebulizer; the concentration within the exposure chamber was controlled by adjusting the rate of the infusion pump. The chamber flow rate was maintained at 60 L/min providing 120 air changes per hour.
- Method of particle size determination: Particle size was determined using a cascade impactor. The device consisted of six impactors stages. The mean amount for each stage was used to determine the cumulative amount below each cut-off point size to calculate the proportional (%) aerosol of defined size ranges. The resulting values were converted to probits and plotted against Log10 cut-point size. From this plot, the Mass Median Aerodynamic Diameter (MMAD) was determined (as the 50% point) and the geometric standard deviation was calculated. In addition the proportion (%) of aerosol less than 4 μm (considered to be the inhalable fraction) was determined.
- 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. The chamber was maintained under negative pressure.
- Temperature, humidity, in air chamber: The temperature and relative humidity inside the exposure chamber were measured by an electronic thermometer/humidity meter: 19 to 20 °C and 71 to 80% humidity within the exposure chamber.

- Brief description of analytical method used: The test atmosphere was sampled nine times during the exposure period. The sampling procedure involved 2 litres of test atmosphere being drawn through a glass fibre filter. Each filter was then submitted for chemical analysis by gas chromatography (GC). The test filter samples received were extracted with methanol to achieve the working concentration. Blank filters were accurately fortified with known amounts of test item and either analysed without further procedure or purged with nitrogen prior to analysis. A range of standard solutions were prepared in methanol from a stock solution of 1 mg/mL by serial dilution covering the concentration range 0 to 0.1697 mg/mL. Full details of the analytical method are provided in the full study report. The linearity of the analytical system used for sample analyses was demonstrated with a good relationship between peak areas measured and working standard concentrations. The regression coefficients calculated were found to be 0.999. The fortified samples of filters were found to have a recovery value of ± 10% of the fortification.
- Samples taken from breathing zone: yes

- Particle size distribution:
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.):

- Rationale for the selection of the starting concentration: Following an appropriate equilibration period a single group of six rats (three males and three females) was exposed to an atmosphere of the test item for a period of four hours. A target concentration of 5.0 mg/L was used for the exposure. As the mean achieved concentration was 102 % of target and no deaths occurred, no further levels were required. The justification for the starting concentration was based on available data on the test item (by other routes) and the selected target concentration is defined as a limit test in the respective test guideline.
Analytical verification of test atmosphere concentrations:
Duration of exposure:
4 h
5.11 mg/L (from target exposure concentration of 5.0 mg/L)
No. of animals per sex per dose:
3 per sex per dose
Control animals:
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Clinical signs at hourly intervals during exposure, immediately on removal from the restraining tubes at the end of exposure, one hour after termination of exposure and subsequently once daily for up to fourteen days. Any evidence of overt toxicity was recorded at each observation.Individual body weights were recorded on arrival, prior to treatment on the day of exposure and on Days 1, 3, 7 and 14.
- Necropsy of survivors performed: yes

Results and discussion

Effect levels
Dose descriptor:
Effect level:
> 5.11 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: Based on a target concentration of 5.0 mg/L; As the mean achieved concentration was 102 % of target and no mortality occurred, no further dose levels were required.
No mortality was observed.
Clinical signs:
other: Common abnormalities noted during the study included increased respiratory rate, hunched posture, pilo-erection and wet fur. Full recovery to appear normal on Day 5 post-exposure.
Body weight:
All animals exhibited body weight losses or showed no body weight gain on the first day post-exposure.
Two female animals exhibited either a body weight loss or showed no body weight gain from Days 3 to 7 post-exposure.
Reasonable body weight gains were noted in all other animals during the remainder of the recovery period.
Gross pathology:
No abnormalities were noted at necropsy.
Other findings:
- Other observations: The respiratory tract was subjected to a detailed macroscopic examination for signs of irritancy or local toxicity during necropsy; none was reported post exposure.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
EU criteria not met
Under the conditions of this study the inhalation LC50 was established to exceed 5.11 mg/L in male and female Wistar rats.
Executive summary:

The study was performed according to OECD TG 436 and in accordance with GLP to assess the acute inhalation toxicity of the test substance. A group of Wistar rats comprising three males and three females was exposed to an aerosol atmosphere for four hours using a nose only exposure system, followed by a fourteen day observation period. The target concentration was 5.0 mg/L and the mean achieved atmosphere concentration was 5.11 mg/L. The additional characteristics of the atmosphere was Mean Mass Median Diameter (particle size) 3.42 μm ; Inhalable Fraction <4 μm was 57.5% with a geometric standard deviation of 2.30. There was no mortality and no macroscopic abnormalities were detected amongst animals at necropsy. Body weight losses exhibited or no gains were seen on the first day post-exposure. Two female animals exhibited either a body weight loss or showed no body weight gain from days 3 to 7 post-exposure. Reasonable body weight gains were noted in all other animals during the remainder of the recovery period. Under the conditions of this study the acute inhalation LC50 was established to exceed 5.11 mg/L in male/female Wistar rats.

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