Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
09 December 2011 to 23 December 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)
Version / remarks:
(2009)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Swiss Confideration, Swiss Federal Office of Public Health, Consumer protection directorate, Notification authority for chemicals, Bern, Switzerland
Test type:
acute toxic class method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): (Chloromethyl)triethoxysilane
- Physical state: colourless liquid
- Lot/batch No.: KH09731
- Analytical purity: 97.3% (GC)
- Purity test date: 13 July 2011
- Expiration date of the lot/batch: 11 July 2013
- Storage condition of test material: at room temperature (20±5 °C) protected from direct sunlight
- Other: The test item was used as analytical standard.

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Strain: RccHan:WIST(SPF)
- Source: Harlan Laboratories B.V. (Kreuzelweg 53, 5961 NM Horst, Netherlands)
- Age at study initiation: 9 weeks
- Weight at study initiation: 278.0-282.6 g (males) and 181.8-193.5 g (females) The weight variation did not exceed ±4% of the mean weight of the corresponding sex.
- Fasting period before study: none
- Housing: in groups of 3 of the same sex in Makrolon® type-IV cages with wire mesh tops and standard softwood bedding ("Lignocel" J. Rettenmaier & Söhne GmbH & Co KG, 73494 Rosenberg, Germany, imported by Provimi Kliba AG, 4303 Kaiseraugst, Switzerland) including paper enrichment (Enviro-dri from Lillico Biotechnology, Surrey, UK)
- Diet: pelleted standard Harlan Teklad 2914C rat maintenance diet (Provimi Kliba AG, 4303 Kaiseraugst, Switzerland) batch no. 44/11, ad libitum except during the period when the animals were restrained in exposure tubes
- Water: Community tap water from Füllinsdorf in water bottles, ad libitum except during the period when they were restrained in exposure tubes
- Acclimation period: 9 days under optimal hygienic laboratory conditions; the animals were accustomed to the restraining tubes for 30 minutes on the day of exposure

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12 (A radio program was played during most of the light period.)

IN-LIFE DATES: from 09 December 2011 to 23 December 2011

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
nose only
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Inhalation exposure was performed using a flow-past, nose-only exposure system. The exposure system ensured a uniform distribution and provided a constant flow of test material to each exposure tube.
- Exposure chamber volume:
- Method of holding animals in test chamber: The animals were confined separately in restraint tubes which were positioned radially around the exposure chamber.
- Rate of air: The flow of air at each tube was 1.0 L/min, which is sufficient to minimize re-breathing of the test atmosphere as it is more than twice the respiratory minute volume of rats.
- System of generating vapour: The test atmosphere was generated using a glass nebulizer with a metal injector connected to a syringe pump. The temperature of the glass nebulizer was kept at 70°C to maximize the vaporization of the test item. A particle filter was placed before the exposure chamber to ensure that any aerosol droplets were retained and that the animals were exposed only to the vapour phase.
- Temperature, humidity, oxygen in air chamber: 22.3-22.4 °C, 2.9-3.0% relative humidity, 20.2% (v/v) oxygen concentration

TEST ATMOSPHERE
- Brief description of analytical method used: The nominal concentration was determined during exposure by weighing the nebulizer and appropriate adjacent pipe work, before and after exposure to determine the quantity of test item used for test atmosphere generation. The weight used was then divided by the total airflow volume to give the nominal concentration.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: technically highest achievable concentration as vapour
Analytical verification of test atmosphere concentrations:
yes
Remarks:
Test atmosphere samples were collected 4 times during exposure in a solvent trap with 100 ml acetonitrile at 20±5 °C. The duration of sampling was 10-12 min. The samples were stored at -20±5 °C until analysis using a GC method.
Duration of exposure:
4 h
Concentrations:
- Target concentration: approx. 4.5 mg/l air
- Nominal vapour concentration: 7.0 mg/ml air
- Analytical concentration: 4.7 mg/ml air
No. of animals per sex per dose:
3
Control animals:
other: not required
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations for viability/mortality: Observations for viability were recorded once before exposure on the day of exposure (test day 1), three times during exposure, immediately and 1 h after exposure on test day 1 and twice daily during the observation period.
- Frequency of observations for clinical signs: Each animal was examined three times during exposure, immediately and 1 h after exposure on test day 1 and once daily during the observation period.
- Frequency of weighing: The body weight of each animal was recorded on test days 1 (before exposure), 2, 4, 8 and 15 (before necropsy).
- Necropsy of survivors performed: yes. Samples of the following tissues and organs were collected from all animals at necropsy and fixed in neutral phosphate buffered 4% formaldehyde solution (head with nasopharyngeal tissues, larynx, lungs: instilled via trachea with formalin at approximately 30 cm H2O pressure, trachea). All collected organ and tissue samples were retained but neither processed nor examined.
- Other examinations performed: clinical signs, body weight
Statistics:
No statistical analysis was performed as only one group was allocated to the study.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 4 700 mg/m³ air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: No mortality occured. The test concentration of 4700 mg/m³ air was the highest vapour concentration achievable.
Mortality:
All animals survived the scheduled observation period.
Clinical signs:
During exposure, salivation and reddish nasal secretion were observed in all three males and in one or two females, respectively. After the end of treatment, ruffled fur was noted for all animals. In addition, decreased activity and hunched posture were recorded for two males and in two or all three females, respectively. There were no clinical signs recorded from test day 2 until the end of the observation period.
Body weight:
From test day 1 to test day 2, slight body weight loss was noted in all animals. Thereafter normal body weight development was recorded.
Gross pathology:
No macroscopic findings were present at necropsy.

Any other information on results incl. tables

TEST ATMOSPHERE CONDITIONS

Temperature, relative humidity and oxygen concentration during exposure were considered to be

satisfactory for this type of study.

Tab. 1: Data on temperature, relative humidity and oxygen concentration

Recording Time

[hours/min]

 

O2Concentration

[Vol %]

 

Temperature

[°C]

 

Relative Humidity

[% RH]

07:00

20.2

22.2

3.0

07:30

20.2

22.3

3.0

08:00

20.2

22.3

3.0

08:30

20.2

22.3

2.9

09:00

20.2

22.4

2.9

09:30

20.2

22.4

2.9

10:00

20.2

22.4

2.9

10:30

20.2

22.4

2.9

11:00

20.2

22.4

2.9

Mean

20.2

22.3

2.9

SD

0.0

0.0

0.0

N

9

9

9

CHEMICAL DETERMINATION OF VAPOR CONCENTRATION

Tab. 2: Details on chemically determined vapor concentrations

Sampling Time

[hours/min]

 

Sampling Volume

[l]

 

Amount of Test Item in

the Solvent Trap

[mg]

 

Chemical Vapor

Concentration

[mg/l air]

07:26-07:36

9.8

46.2

4.7

08:34-08:46

11.8

57.0

4.8

09:17-09:27

9.8

45.4

4.6

10:15-10:27

11.8

55.4

4.7

          Mean

4.7

          SD

0.1

          N

4

Applicant's summary and conclusion

Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008
Conclusions:
The test item was tested for acute inhalation toxicity according to the OECD TG 436, and in compliance with GLP. Treatment with the test item at a concentration of 4700 mg/m³ air for 4 h resulted in clinical signs (salivation, reddish nasal secretion, ruffled fur, decreased activity and hunched posture) and body weight loss. This observation exceeded the marginal body weight loss or stagnation of the body weight gain which is usually observed in acute inhalation studies. However, the restraining of the animals in the tubes during the nose-only exposure procedure may have added to the observed effect. In conclusion, the LC50 was > 4700 mg/m³ air, which was the technical limit concentration for a vapour. Hence, classification for actute inhalation toxicity according to EC/1272/2008 is not warranted.
Executive summary:

A group of three male and three female albino rats [RccHanTM:WIST(SPF)] was exposed by nose-only, flow-past vapor inhalation for four hours to the test item at a chemically determined mean concentration of 4.7 mg/l air. All animals were observed for clinical signs and mortality during the inhalation exposure and the subsequent 14-day observation period. Body weights were recorded prior to exposure on test day 1, and during the observation period on test days 2, 4, 8 and 15 before necropsy. On test day 15 all animals were sacrificed and necropsied. The vapor concentration, temperature, relative humidity, oxygen content and airflow rate measured during the exposure were considered to be satisfactory for a study of this type. In addition, as a vapor the test item was considered to be respirable to rats. All animals survived the scheduled observation period. Most animals showed salivation and reddish nasal secretion during exposure and ruffled fur, decreased activity and hunched posture thereafter. There were no clinical signs recorded from test day 2 onwards. From test day 1 to test day 2, slight body weight loss was noted in all animals. Thereafter normal body weight development was recorded. No macroscopic findings were present at necropsy. In conclusion, the LC50 for 4-hour exposure of (chloromethyl)triethoxysilane obtained in this study was greater than 4.7 mg/l air (chemically determined mean vapor concentration). This concentration was at the technical limit for a vapor and considered to be close to the saturation concentration. There was no indication of relevant sex-related differences in toxicity of the test item.