N-(3-(trimethoxysilyl)propyl)ethylenediamine

Endpoint summary

Description of key information

The key study for acute oral toxicity determined an LD50 value of 2295 mg/kg bw in rats, in a reliable study conducted according to an appropriate test protocol and in compliance with GLP (Dow Corning Corporation, 2001).

The key study for acute inhalation toxicity determined an LC50 value of 1.49 - 2.44 mg/l in rats, in a reliable study conducted according to an appropriate test protocol and in compliance with GLP (Dow Corning Corporation, 2000a).

The key study for acute dermal toxicity determined an LD50 value of >2000 mg/kg bw in rabbits, in a reliable limit test conducted according to an appropriate test protocol and in compliance with GLP (Dow Corning Corporation, 2000b).

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14.09.1998 to 09.02.2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: No data
- Age at study initiation: 7-12 weeks
- Weight at study initiation: 202-286 g
- Fasting period before study: Yes, overnight
- Housing: Individually, in suspended metal cages with mesh floors
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Seven days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22± 3
- Humidity (%): 30-70
- Air changes (per hr): Minimum of 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 24.09.1998 To: 25.11.1998

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 4.954 ml/kg

Doses:

500, 1200 (initially only two males and two females were treated on humane grounds to ensure the dose level selected did not result in greater than 50% mortality), 1200, 3000 and 5000 mg/kg bw

No. of animals per sex per dose:

Five

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All rats were observed daily for mortality and morbidity. The bodyweight of each rat was recorded on Days 1 (prior to dosing, 8 and 15 (or at death). Clinical signs were observed immediately after dosing and at approximately hourly intervals for the remainder of Day 1. On subsequent days animals were observed twice daily.
- Necropsy of survivors performed: yes
- Other examinations performed: Macroscopic examination

Statistics:

The acute median lethal dose was calculated using the method of Finney.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

2 295 mg/kg bw

Based on:

test mat.

95% CL:

>= 1 539 - <= 3 423

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

1 897 mg/kg bw

Based on:

test mat.

95% CL:

>= 1 077 - <= 3 343

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

2 574 mg/kg bw

Based on:

test mat.

95% CL:

>= 1 931 - <= 3 431

Mortality:

Four males and all five females treated with 3000 mg/kg bw and all of those at 5000 mg/kg bw died during the study. Deaths occurred between 2 hours and Day 2. There were no deaths in the other groups.

Clinical signs:

other: Piloerection (all doses), hunched posture, waddling/unsteady gait, pallid extremities, eyes dulled, increased salivation, abnormal respiration, ungroomed appearance, fecal disturbances, increased sensitivity and increased lacrimation (among rats at 1200,

Gross pathology:

All animals that died had congestive changes in the majority of organs and tissues. There were no changes in animals that survived to the end of the observation period.

Interpretation of results:

GHS criteria not met

Conclusions:

In an acute oral toxicity study conducted to EPA OPPTS 870.1100 (Acute Oral Toxicity) and to GLP (reliability score 1) the LD50 for N-(3-(trimethoxysilyl)propyl)ethylenediamine was 2295 mg/kg bw in rats. Piloerection (all doses), hunched posture, waddling/unsteady gait, pallid extremities, eyes dulled, increased salivation, abnormal respiration, ungroomed appearance, fecal disturbances, increased sensitivity and increased lacrimation (among rats at 1200, 3000 and/or 5000 mg/kg bw), walking on toes, blue/cold extremities, lethargy, partially closed eyelids and body tremors (3000 and 5000 mg/kg bw) and prostration (5000 mg/kg bw). These clinical signs had resolved by Day 6. All animals that died had congestive changes in the majority of organs and tissues. There were no changes in animals that survived to the end of the observation period.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

2 295 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05.10.1998 to 22.06.2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Species:

rat

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River UK Limited
- Age at study initiation: 7-8 wk
- Weight at study initiation: 186-345g
- Fasting period before study: no
- Housing: Stainless steel sheet and wire mesh suspended cages (holding cages)
- Diet (e.g. ad libitum): Ad libitum (except during exposure)
- Water (e.g. ad libitum): Ad libitum (except during exposure)
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21± 2
- Humidity (%): 55± 10
- Air changes (per hr): 12-15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 09.11.1998 To: 06.04.1999

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: whole body exposure chamber
- Exposure chamber volume: The whole body exposure chambers were 51 cm x 51 cm x 38 cm. The chambers were fitted with a pyramidal top section with an enclosed volume of approximately 120 litres.
- Method of holding animals in test chamber: Individual compartments
- Source and rate of air: Compressed air line at flow rate of 25 l/min
- Method of conditioning air: filtered, dried and oil-free
- System of generating aerosols: The test substance was metered at a constant rate from a polypropylene syringe mounted on a syringe pump to a stainless steel concentric jet atomiser. The aerosol produced passed through a 2-piece glass elutriator prior to entering the exposure chamber. During the first exposure with animals the test substance was observed to form a solid substance on contact with water. It was considered that the water vapour produced by the animals during exposure resulted in most of the silane in the chamber being converted to an aerosol of this solid.
- Method of particle size determination: Two additional air samples were taken during the exposure, at a sampling rate of 2 l/min, using a Marple cascade impactor. The amount of test substance collected on the stages of the sampler was determined gravimetrically. The particle size distribution of the test substance was assessed using linear regression analysis of the probit of the cumulative percentage of the total particles collected, smaller that the cut-point of each stage, against the logarithm of the cut-point of each stage.
- Treatment of exhaust air: Test atmosphere was extracted through a perforated base into a large extract cabinet exhausting to atmosphere through an absolute filter.
- Temperature, humidity, pressure in air chamber: 21-23 oC, 39-61%, pressure not clear

TEST ATMOSPHERE
- Brief description of analytical method used: At least five samples of air were removed from the test chamber at intervals during each exposure in order to determine the concentration of the test aerosol. Following the first exposure each air sample was withdrawn through a pre-weighed glass fibre filter mounted in an open face filter holder. The filters were re-weighed following sampling for gravimetric analysis of the test aerosol. For the first test group exposure only, in addition to sample collected on glass fibre filters, attempts were made to collect samples using sintered glass bubblers containing toluene as trapping agent to determine the actual silane concentration by chemical analysis. It had previously been determined that the aerosol of the silane formed a solid substance on contact with water vapour in air, which could not be analysed chemically with the method established. Therefore analysis of the test atmosphere produced from the test substance was analysed by gravimetric means only.
- Samples taken from breathing zone: Not clear from information given.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Target: 0.5, 1.0, 1.5, 2.0 and 5.0 mg/l
Analysed: 0.515, 1.06, 1.49, 2.44 and 5.75 mg/l

No. of animals per sex per dose:

Five

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The rats were observed continuously for signs of reaction during exposure and at least twice daily throughout the observation period. The clinical signs were recorded at the end of the chamber equilibrium period, 0.25, 0.5 and 1.0 hours into exposure then at hourly intervals during the remainder of the exposure. Signs were also recorded immediately after exposure and at 1 and 2 hours after exposure. During the observation period, signs were recorded twice daily. All rats were weighed at least twice during the week prior to exposure, immediately before exposure and weekly during the observation period.
- Necropsy of survivors performed: yes
- Other examinations performed: The amount of food consumed by each cage of rats was measured from weigh day to weigh day throughout the study. The amount of water consumed by each cage of rats was measured daily from Day 2 of the observation period following the gross observation of reduced consumption in the test rats. A complete macroscopic examination of each rat was performed. The lungs, liver and kidneys were weighed.

Statistics:

None

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1.49 - < 2.44 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

See Table 2.

Clinical signs:

other: During exposure: Signs related to exposure to the test aerosol comprised exaggerated breathing and partially closed eyes in all test groups and reduced motor activity in exposure groups 0.515 to 2.44 mg/l. During the observation period: Irregular noisy a

Body weight:

A dose-related reduction in body weight gain over the observation period was observed in animals from 0.515 to 1.49 mg/l.

Gross pathology:

Severely congested lungs were observed in all deceased animals. The observation is considered to be associated with the cause of death. Areas of severe congestion together with pale raised hardened areas were also observed in the surviving female exposed to 5.75 mg/l. Pale raised lungs were also observed in the lungs of a proportion of surviving rats of both sexes in all other groups exposed to the test aerosol.

Other findings:

Food consumption by test groups was lower than that of the control group during the observation period.

Surviving female rats exposed to 2.44 or 5.75 mg/l had lung weights greater than control rats. In all other surviving animals from other test groups there were no differences in organ weights that were considered to be a direct effect of exposure to the test aerosol. Lower liver weights observed in test group survivors were considered to be a secondary effect of reduced body weight gains.

Table 2 Summary of mortality data

Group (mg/l)	Mortality
	Male	Female	Total
0	0/5	0/5	0/10
0.515	0/5	0/5	0/10
1.06	0/5	0/5	0/10
1.49	0/5	0/5	0/10
2.44	5/5	3/5	8/10
5.75	5/5	4/5	9/10

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

In an acute inhalation (aerosol) study conducted to EPA OPPTS 870.1300, which is comparable to OECD 403, and to GLP (reliability score 1) the LC50 for N-(3-(trimethoxysilyl)propyl)ethylenediamine was 1.49 -2.44 mg/l.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

1 490 mg/m³ air

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14.09.1998 to 25.02.2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: No data
- Age at study initiation: At least 12 weeks
- Weight at study initiation: 2494-2828 kg
- Fasting period before study: No
- Housing: Individually in suspended metal cages with perforated floors
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-22
- Humidity (%): 40-65
- Air changes (per hr): 15-19
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 24.09.1998 To: 08.10.1998

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: lumbar region
- % coverage: approximately 10%
- Type of wrap if used: porous (< 8 ply) gauze held in place with a non irritating dressing, and further covered by a waterproof dressing

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit):1.982 mL/kg bw

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Five

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All rabbits were observed twice daily for mortality and morbidity. The bodyweight of each animal was recorded on Days 1 (prior to dosing), 8 and 15. Animals were observed immediately after dosing and at approximately hourly intervals for the remainder of Day 1. On subsequent days animals were observed twice.
- Necropsy of survivors performed: yes
- Other examinations performed: Dermal responses were examined on Day 2 to 15. Skin reactions were scored according to the Draize scoring system. A gross macroscopic examination of each animal was conducted.

Statistics:

Mean body weights were calculated. No other statistical analyses were conducted.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: No deaths.

Mortality:

No deaths occurred.

Clinical signs:

other: There were no treatment-related clinical signs of toxicity, except fecal disturbance in one female rabbit.

Gross pathology:

No abnormal findings.

Other findings:

Persistent slight to moderate irritation (erythema with or without oedema up to Grade 3) was evident in all rabbits following removal of the dressings and over the following days. These reactions had notably ameliorated by the second week of the study with resolution in all but three animals complete by Day 15. In the remaining rabbits slight erythema (Grade 1) was still evident at study termination. Also notable in all rabbits during the first days following treatment was a very dry texture to the skin over the treatment site, desquamation of the skin on the treatment site (all rabbits and present in six rabbits at study termination) and in one rabbit localised necrosis/blanching evident throughout the observation period.

Interpretation of results:

GHS criteria not met

Conclusions:

In an acute dermal toxicity study conducted to EPA OPPTS 870.1200 (Acute Dermal Toxicity) and to GLP (reliability score 1) the LD50 for N-(3-(trimethoxysilyl)propyl)ethylenediamine was at least 2000 mg/kg bw in rabbits. No deaths occurred at this dose. There were no clinical signs, macroscopic findings, or significant effects on bodyweight. The only findings were irritation at the application site.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

> 2 000 mg/kg bw

Additional information

There are good quality data for all relevant routes of exposure.

The key study on acute oral toxicity study conducted to EPA OPPTS 870.1100 (Acute Oral Toxicity) and to GLP (Dow Corning Corporation, 2001) identified an LD₅₀ for N-(3-(trimethoxysilylpropyl)ethylenediamine of 2295 mg/kg bw in rats. Piloerection was present at all doses, hunched posture, waddling/unsteady gait, pallid extremities, eyes dulled, increased salivation, abnormal respiration, ungroomed appearance, fecal disturbances, increased sensitivity and increased lacrimation (among rats at 1200, 3000 and/or 5000 mg/kg bw), walking on toes, blue/cold extremities, lethargy, partially closed eyelids and body tremors (3000 and 5000 mg/kg bw) and prostration (5000 mg/kg bw) were seen in test animals. These clinical signs had resolved by Day 6. All animals that died had congestive changes in the majority of organs and tissues. There were no changes in animals that survived to the end of the observation period.

Several supporting studies were also available for acute oral toxicity, of which of the reliable studies are briefly described here. A reliable study conducted to the now deleted OECD 401 but not in compliance with GLP, identified an LD₅₀ of 7.46 ml/kg bw in male rats (Mellon Institute, 1966a). A fairly briefly reported reliable study, conducted according to generally accepted scientific standards but prior to GLP, reported an LD₅₀ in rats of 7.46 ml/kg bw (Mellon Institute, 1975a). A reliable study conducted in compliance with the now deleted OECD test guideline 401 and GLP, identified an oral LD₅₀ of 2400 mg/kg bw for male and females rats, treated (Hazleton, 1992). The available studies support the key findings for acute oral toxicity.

The key study for acute inhalation was conducted to EPA OPPTS 870.1300, which is comparable to OECD 403, and to GLP (Dow Corning Corporation, 2000a). The test animals were exposed to 0.515, 1.06, 1.49, 2.44 and 5.75 mg/l aerosol concentration of the test substance. An LC₅₀ of 1.49 -2.44 mg/l was identified. Signs related to exposure to the test aerosol comprised exaggerated breathing and partially closed eyes in all test groups and reduced motor activity in exposure groups 0.515 to 2.44 mg/l. A dose-related reduction in body weight gain over the observation period was observed in animals from 0.515 to 1.49 mg/l. There were mortalities at 2.44 and 5.75 mg/l. Severely congested lungs were observed in all deceased animals. The observation is considered to be associated with the cause of death. Areas of severe congestion together with pale raised hardened areas were also observed in the surviving female exposed to 5.75 mg/l. Pale raised lungs were also observed in the lungs of a proportion of surviving rats of both sexes in all other groups exposed to the test aerosol.

The key study in acute dermal toxicity study was conducted to EPA OPPTS 870.1200 (Acute Dermal Toxicity) and to GLP (Dow Corning Corporation, 2000b). An LD₅₀ of >2000 mg/kg bw in rabbits was identified. No deaths occurred at this dose. There were no clinical signs, macroscopic findings, or significant effects on bodyweight. The only findings were irritation at the application site. Persistent slight to moderate irritation (erythema with or without oedema up to Grade 3) was evident in all rabbits following removal of the dressings and over the following days. These reactions had notably ameliorated by the second week of the study with resolution in all but three animals complete by Day 15. In the remaining rabbits slight erythema (Grade 1) was still evident at study termination. Also notable in all rabbits during the first days following treatment was a very dry texture to the skin over the treatment site, desquamation of the skin on the treatment site (all rabbits and present in six rabbits at study termination) and in one rabbit localised necrosis/blanching evident throughout the observation period.

Two reliable supporting studies were also available for acute dermal toxicity. An acute dermal toxicity study conducted to OECD 402 and to GLP identified an LD₅₀ value of >2009 mg/kg bw (Hazleton, 1992). There were no deaths, clinical effects or abnormal macroscopic findings at this dose.A fairly briefly reported study, conducted according to generally accepted scientific standards but prior to GLP, reported an LD₅₀ in rabbits greater than 16 ml/kg bw (Mellon Institute, 1975).

Justification for classification or non-classification

Based on the available data N-(3-(trimethoxysilyl)propyl)ethylenediamine is classified 'Acute Toxic 4 (mist)' with the hazard statement 'H332: Harmful if inhaled' under Regulation (EC) No 1272/2008. This substance is not classified for acute toxicity following oral or dermal exposure.