3-aminopropyltriethoxysilane

Endpoint summary

Description of key information

The key 90-day oral (gavage) repeated dose toxicity study in male and female rats, conducted according to OECD Test Guideline 408 and in compliance with GLP, identified a NOAEL value of 200 mg/kg bw/day, with mortality, clinical findings and liver effects at the LOAEL of 600 mg/kg bw/day (WIL, 2001).

A 28-day repeated dose inhalation study, conducted according to a protocol similar to OECD Test Guideline 412 and in compliance with GLP, recorded local effects in the larynx, olfactory and nasal mucosa, trachea and lungs at 147 mg/L (the only dose tested) (BRRC, 1991).

A repeated dose dermal study conducted according to a protocol similar to an appropriate OECD guideline and in compliance with GLP, showed no systemic effects following 9 doses of 84 mg/kg bw/day (BRRC, 1990).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999-10-11 to 2000-03-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Crl:CD (SD)IGS BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Labs, Raleigh, NC, USA
- Age at study initiation: 7 wk
- Weight at study initiation: 213-279 g (m); 150-207 g (f)
- Housing: 1/suspended wire mesh cage
- Diet: standard diet ad libitum
- Water: drinking water ad libitum
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 70.2-73.3 deg F
- Humidity (%): 35.2-58.5
- Photoperiod (hrs dark / hrs light): 12 h/12 h

IN-LIFE DATES: From: 1999-10-11 To: 2000-01-11

Route of administration:

oral: gavage

Vehicle:

peanut oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: vehicle dispensed daily; mixed with magnetic stirrer

Dose volume: 10ml/kg bw/day

VEHICLE
- Justification for use and choice of vehicle: peanut oil sparged with nitrogen
- Concentration in vehicle: 0, 7, 20, 60 mg/ml
- Lot/batch no. : NQ0052 and NG0346

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

atomic absorption spectroscopy

Duration of treatment / exposure:

91 or 92 consecutive days

Frequency of treatment:

Daily

Dose / conc.:

70 mg/kg bw/day (actual dose received)

Remarks:

2-wk range finding study (WIL-242147)

Dose / conc.:

200 mg/kg bw/day (actual dose received)

Remarks:

2-wk range finding study (WIL-242147)

Dose / conc.:

600 mg/kg bw/day (actual dose received)

Remarks:

2-wk range finding study (WIL-242147)

No. of animals per sex per dose:

15

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: Not applicable. All animals were euthanized and necropsied upon completion of the treatment period; no recovery or other satellite groups were included.

Positive control:

None

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION:
Food intake was calculated as g/animal/day for the corresponding body weight intervals. When food consumption could not be measured for a given interval (due to spillage, weighing error, etc.), the appropriate interval was footnoted as "NA" (Not Applicable) on the individual tables.

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: prior to treatment and during wk 12
- Dose groups that were examined: . Ocular examinations were conducted on all animals. All ocular examinations were conducted using an indirect ophthalmoscope, preceded by pupillary dilation with an appropriate mydriatic agent
HAEMATOLOGY: Yes
- Time schedule for collection of blood: wks 4, 13
- Animals fasted: Yes, overnight
Blood samples for general clinical pathology evaluations were collected from a lateral tail vein at both time points. Blood samples for assessment of coagulation parameters were collected from the vena cava at the time of necropsy. The following hematology parameters were evaluated: total leukocyte count (white cell), erythrocyte count (red cells), hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), platelet count, prothrombin time, activated partial thromboplastin time (APTT; terminal evaluation only), reticulocyte count (percent and absolute), differential leukocyte count (percent and absolute: neutrophil, lymphocyte, monocyte, eosinophil and basophil).

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: wks 4, 13
The following serum chemistry parameters were evaluated: alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, blood urea nitrogen, total protein, total bilirubin, creatinine, Ca, Na, K, Cl, P, glucose, albumin, globulin, albumin/globulin ratio, and total cholesterol.

URINALYSIS: Yes
- Metabolism cages used for collection of urine: Yes
Urine samples were collected via metabolism chambers following the eighth exposure of female rats and following the seventh exposure of male rats. Urine volume was measured using calibrated test tubes, and urine color and turbidity were visually assessed. Urinalysis parameters were urine osmolality, pH, protein, glucose, ketone, bilirubin, blood and urobilinogen.

NEUROBEHAVIOURAL EXAMINATION: No

OTHER:
Vaginal smears for determination of the stage of estrus were obtained from all surviving females once daily beginning 21 days prior to the scheduled necropsy. The average cycle length was calculated for complete estrous cycles (i.e., the total number of returns to metestrus [M] or diestrus [D] from estrus [E] or proestrus [P]) beginning 21 days prior to the scheduled necropsy. The final vaginal smear for each female was collected on the day of necropsy.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
A complete necropsy was conducted on all animals. The necropsy included, but was not limited to, examination of the external surface, all orifices and the cranial, abdominal and pelvic cavities and their viscera.

HISTOPATHOLOGY: Yes
At the time of necropsy, the following tissues and organs were collected and preserved in 10% neutral buffered formalin: adrenals (2), aorta, bone with marrow (femur, sternebrae), bone marrow smear (from femur), brain (forebrain, midbrain, hindbrain), coagulating gland, eyes with optic nerve (2; preserved in Davidson's solution), gastrointestinal tract (esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, rectum), heart, kidneys (2), liver (sections of two lobes), lungs (including bronchi, fixed by inflation with fixation), lymph node (mesenteric, submandibular), mammary gland (females only), ovaries with oviducts (2), pancreas, peripheral nerve (sciatic), pituitary, prostate, salivary glands (submaxillary, 2), seminal vesicles (2), skeletal muscle (vastus medialis), skin, spinal cord (cervical, midthoracic, lumbar), spleen, testis with epididymis (1) and vas deferens, thymus, thyroid (with parathyroids if present (2)), trachea, urinary bladder, uterus with vagina and cervix, and all gross lesions (when possible). Bone marrow smears were obtained from all animals not found dead, but were not placed in 10% neutral buffered formalin. The right testis/epididymis from all males at the scheduled necropsy and both testes/epididymides from those males found dead were preserved in Bouin's solution and prepared for microscopic examination using PAS/hematoxylin staining. The left testis/epididymis from all males euthanized at the scheduled necropsy were prepared for sperm analysis as described below. The following organs from animals euthanized at the scheduled necropsy were weighed: adrenals, brain, epididymides (weighed separately; total and cauda), kidneys, liver, ovaries (with oviducts), pituitary, prostate, seminal vesicles with coagulating glands (with accessory fluids), testes (weighed separately), and thyroid (fixed weight). Organ to final body weight and organ to brain weight ratios were calculated. The tissues noted above from all animals found dead or euthanized in extremis and from all animals in the control and 600 mg/kg/day groups euthanized at the scheduled necropsy, as well as the lungs, liver, and kidneys from all animals in the 70 and 200 mg/kg/day groups were examined microscopically.

In addition, PAS/hematoxylin-stained sections of the right testis and epididymis from all males were examined microscopically at the scheduled necropsy. Spermatogenic analysis was conducted according to the following protocol. For motility/viability assessment, immediately following euthanasia, the reproductive tract of each male was exposed via a ventral mid-line incision. The right epididymis was excised and weighed separately. An incision was made in the distal region of the cauda epididymis. The cauda was then placed in Dulbecco's phosphate-buffered saline (maintained at approximately 37oC) with 10 mg/ml Bovine Serum Albumin (BSA). A sample of the diluted sperm was then loaded into a 100 µm cannula for determination of motility. As sperm motility can be affected by temperature shock, all cannulas, diluents and slides were pre-warmed and maintained at approximately 37oC. Motility determinations were performed under constant temperature using the Hamilton-Thorne HTM-IVOS Version 10 computer-assisted sperm analysis (CASA) system. At least 200 (if possible) motile and nonmotile spermatozoa/animal were analyzed. A sample of sperm for morphology assessment was obtained from the right cauda epididymis of each male. Sperm morphology was evaluated using a modification of the wet-mount technique described by Linder et al., 1992. Abnormal forms of sperm (double heads, double tails, micro- or megacephalic, etc.) were recorded from a differential count of 200 spermatozoa/animal. For enumeration of epididymal and testicular sperm numbers and sperm production rates, the left testis and epididymis from each male at the scheduled necropsy were weighed and frozen, then homogenized and evaluated for sperm production rate using the method described by Blazak et al., 1985. Analyses were performed using the Hamilton-Thorne CASA system.

Statistics:

All analyses were conducted using two-tailed tests for minimum significance levels of 1% and 5% comparing the test article-treated groups to the control group by sex. All means were presented with standard deviations (S.D.) and the number of sampling units (N) used to calculate the means. Statistical analyses were not conducted if the number of animals was two or less. All statistical tests were performed using appropriate computing devices or programs. Body weight, body weight change, food consumption, clinical pathology, absolute and relative organ weight data and epididymal and testicular sperm numbers and sperm production rates were subjected to a one-way analysis of variance (ANOVA), followed by Dunnett's test if the ANOVA revealed statistical significance (p<0.05). The percentage of motile spermatozoa and the percentage of sperm with normal morphology were analyzed by the Kruskal-Wallis nonparametric ANOVA test to determine intergroup differences, followed by the Mann-Whitney U-Test comparing the control and test article-treated groups if the ANOVA revealed statistical significance (p<0.05). Clinical laboratory values for leukocytes that occur at a low incidence (i.e., monocytes, eosinophils and basophils) were not subjected to statistical analysis.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Clinical signs included laboured breathing/gasping, partially closed eyes, pallor, hypothermia, dermal atonia and/or tremor. The predominant clinical sign in surviving animals was rales (rattling/crackling sound during breathing) following exposure to 600 mg/kg/day. Furthermore, at 600 mg/kg/day, wet and/or dried material on various parts of the body and abnormal excreta were observed. These signs were observed sporadically at lower doses.

Mortality:

mortality observed, treatment-related

Description (incidence):

At 600 mg/kg bw/day, death of 1 male and 8 females occurred and was considered as a treatment related effect. Moreover, one male in the control group, one female at 200 mg/kg bw/day as well as two males at 600 mg/kg bw/day died which were not considered to be treatment-related since the latter were due to dosing error.

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Increased mean aspartate aminotransferase (AST) values for males at week 13 and alanine aminotransferase (ALT) for both sexes at weeks 4 and 13 (greatest at week 13), were associated (in males) with liver weight increases and cellular changes seen on microscopic examination. Transient or sporadic variations in serum urea nitrogen and sodium were not considered biologically significant.

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Increased liver weights in high dose males (non statistically significant increase in mean liver:brain weight; statistically significant increase in liver:body weight compared to controls) correlated with increased ALT and AST and hepatocellular vacuolation evident on microscopic examination. Increased adrenal weight (absolute, adrenal:brain, adrenal:body weight) in 600 mg/kg bw/day males was not associated with macroscopic, microscopic, haematologic or clinical chemistry findings, and was considered spurious.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

For one male and most females that died prior to scheduled necropsy, macroscopic changes included distension of various parts of the gut. The only macroscopic change at scheduled necropsy was an increased incidence of gaseous distension of the gut, primarily of the cecum, in 7/12 males and 2/7 females in the high dose group.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Microscopic examination revealed changes to the liver of 600 mg/kg bw/day males consisting of centrilobular to generalized hepatocellular vacuolation. No other test article-related microscopic changes were observed.

Histopathological findings: neoplastic:

no effects observed

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

200 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No adverse effects observed at 200 mg/kg bw/day

Dose descriptor:

LOAEL

Effect level:

600 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: mortality, clinical signs, liver effects

Key result

Critical effects observed:

no

Table 1: Summary of mortalities

	Dose (mg/kg bw/day)
	Control		70		200		600
	male	female	male	female	male	female	male	female
died	1/15*	0/15	0/15	0/15	0/15	1/15*	1/15 2/15*	8/15
week of study	4*		-		-	9*	2*, 7	1-6

* dosing error

Conclusions:

A well reported 90-day oral study, conducted in the main according to the current guideline (OECD TG 408) and in accordance with GLP, identified a NOAEL value of 200 mg/kg bw/day in male and female rats. Mortality, clinical observations and liver effects were evident at 600 mg/kg bw/day

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEL

200 mg/kg bw/day

Study duration:

subchronic

Species:

rat

System:

gastrointestinal tract

Organ:

liver

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 1989-08-14 to 1989-09-29

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)

GLP compliance:

yes

Species:

rat

Strain:

Fischer 344

Remarks:

/CDF

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories (Kingston, NY)
- Females nulliparous and non-pregnant: n/a
- Age at study initiation: 20 days
- Weight at study initiation:
- Fasting period before study:
- Housing: 1-2 rats per cage in stainless steel, wire-mesh cages, 23.5 cm * 20cm * 18 cm.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: not specified

DETAILS OF FOOD AND WATER QUALITY: Water was provided by an automatic watering system (Municipal Authority of Westmoreland County, Greensburg, PA)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): not specified
- Humidity (%): not specified
- Air changes (per hr): 13.5
- Photoperiod (hrs dark / hrs light): 12/12 hours.

IN-LIFE DATES: From: 24th of July 1989 to 29th of September 1989 for the control group and from the 18th of July 1989 to 29th of September 1989 for the exposure group.

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

other: water

Mass median aerodynamic diameter (MMAD):

2.92 µm

Geometric standard deviation (GSD):

1.74

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The chambers were of stainless steel with glass windows for animal observations. The chamber volume was 1330 litres.
- Method of holding animals in test chamber: not specified
- Source and rate of air: the airflow was approximately 300 L/min (13.5 air changes per hour).
- Method of conditioning air: not specified
- System of generating particulates/aerosols: A Dwyer Magnehelic pressure gauge
- Temperature, humidity, pressure in air chamber: 18-22°C (64-71°F) with a relative humidity of 46-66 % for the exposed animals and 17-21°C (62-70°F) with a relative humidity of 45-77 % for the animals in the control group.
- Air flow rate: 300 L/min
- Air change rate: 13.5 air changes per hour
- Method of particle size determination: TSI Aerodynamics particle Sizer and a 20:1 diluter.
- Treatment of exhaust air:

TEST ATMOSPHERE
- Brief description of analytical method used:
- Samples taken from breathing zone: not specified

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

6 hours per day for a total of 19 exposures over 4 weeks

Frequency of treatment:

Five days/week for three weeks and four consecutive days during the fourth week

Dose / conc.:

0 mg/m³ air

Remarks:

Control

Dose / conc.:

147 mg/L air (analytical)

Remarks:

Test group

No. of animals per sex per dose:

15 males for the test and control group respectively

Control animals:

other: concurrent; filtered air

Details on study design:

Post-exposure period: Not applicable. The rats were observed daily during exposure and observations were recorded on a group basis. Preceding and following each exposure and on weekends, observations were recorded for animals exhibiting overt clinical signs.

Positive control:

No

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily when not exposed. When exposed, observations were recorded on a group basis.
- Cage side observations checked in table were included: no

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily when not exposed. When exposed, observations were recorded on a group basis.

BODY WEIGHT: Yes
- Time schedule for examinations: weekly including prior to to initiation of the treatment and immediately preceding sacrifice.

FOOD CONSUMPTION AND COMPOUND INTAKE: n/a

FOOD EFFICIENCY: n/a

WATER CONSUMPTION AND COMPOUND INTAKE: No

OPHTHALMOSCOPIC EXAMINATION: Not specified

HAEMATOLOGY: No

CLINICAL CHEMISTRY: No

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

OTHER: Necropsy and histopathology evaluations occurred in all animals being exposed and includes the following tissues: gross lesions, larynx, lungs, trachea, nasal turbinates and kidneys.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Statistics:

The data for continuous and parametric variables were intercompared for the exposure and control groups by use of Levene's test for homogeneity of variances and by t-tests. If Levene's test indicated homogeneous variances, the groups were compared by pooled variance t-tests. If Levene's test indicated heterogeneous variances, the groups were compared by separate variance t-test. Frequency data were compared using Fisher's exact tests. All statistical tests, except the frequency comparisons, were performed using BMDP Statistical Software. The frequency data tests are described in Biometry (Sokal and Rohlf, 1969). The probability value of p 0.05 (two-tailed) was used as the critical level of significance for all tests.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

A significantly lower body weight gain was observed in the exposed animals between the initiation week until week 3. This was considered as not treatment related since the body weights were different prior to the start of the exposure regimen. The difference in preexposure body weight was a result of randomising the animals at different times since they were received at different times. However, body weight gain for the exposure group was statistically lower than the control group during the first week of the study which was considered as treatment related. Body weight gain was comparable or greater than the control group after the first week of exposure. Specifically, body weight gain was statistically significant greater in the exposure group at the end of the 4-week exposure period.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not specified

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not specified

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not specified

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Cytoplasmic hyalinisation (mild to moderate) was observed within the olfactory mucosa of the nasal cavity and was characterised by the presence of smooth homogenous oesinophilic material within the cytoplasm. Two of the rats with laryngeal squamous metaplasia had also minimal degrees of granulomatous laryngitis. Moreover, alveolar histiocytosis, bronchopneumonia and interstitial pneumonitis were observed within the lungs.

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Foci of squamous metaplasia (minimal to mild) were present within the larynx and nasal mucosa of exposed rats. The squamous metaplasia observed in the larynx was observed in the region of the transitional epithelium which is susceptible to toxic injury. Cellular hyperplasia was observed within the trachea of exposed animals. Within the lungs, alveolar type II pneumocyte hyperplasia was observed.

Other effects:

effects observed, non-treatment-related

Description (incidence and severity):

The slightly higher mineralisation of the corneal epithelium and at the corneoscleral junction was not considered to be exposure related since these formations are common in Fischer 344 rat strain and the intergroup frequency of these lesions can vary widely.

Dose descriptor:

LOAEC

Effect level:

>= 147 mg/L air (analytical)

Based on:

test mat.

Sex:

male

Basis for effect level:

body weight and weight gain

histopathology: non-neoplastic

Critical effects observed:

not specified

Conclusions:

In a 28-day repeated inhalation study, which was conducted according to a protocol similar to OECD TG 414 and in compliance with GLP, it was reported that exposure to an aerosol of the test substance hydrolysate (147 mg/L) was associated with laryngeal changes, however, not laryngeal granulomas.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

0.147 mg/m³

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 1989-08-14 to 1989-09-29

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)

GLP compliance:

yes

Species:

rat

Strain:

Fischer 344

Remarks:

/CDF

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories (Kingston, NY)
- Females nulliparous and non-pregnant: n/a
- Age at study initiation: 20 days
- Weight at study initiation:
- Fasting period before study:
- Housing: 1-2 rats per cage in stainless steel, wire-mesh cages, 23.5 cm * 20cm * 18 cm.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: not specified

DETAILS OF FOOD AND WATER QUALITY: Water was provided by an automatic watering system (Municipal Authority of Westmoreland County, Greensburg, PA)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): not specified
- Humidity (%): not specified
- Air changes (per hr): 13.5
- Photoperiod (hrs dark / hrs light): 12/12 hours.

IN-LIFE DATES: From: 24th of July 1989 to 29th of September 1989 for the control group and from the 18th of July 1989 to 29th of September 1989 for the exposure group.

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

other: water

Mass median aerodynamic diameter (MMAD):

2.92 µm

Geometric standard deviation (GSD):

1.74

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The chambers were of stainless steel with glass windows for animal observations. The chamber volume was 1330 litres.
- Method of holding animals in test chamber: not specified
- Source and rate of air: the airflow was approximately 300 L/min (13.5 air changes per hour).
- Method of conditioning air: not specified
- System of generating particulates/aerosols: A Dwyer Magnehelic pressure gauge
- Temperature, humidity, pressure in air chamber: 18-22°C (64-71°F) with a relative humidity of 46-66 % for the exposed animals and 17-21°C (62-70°F) with a relative humidity of 45-77 % for the animals in the control group.
- Air flow rate: 300 L/min
- Air change rate: 13.5 air changes per hour
- Method of particle size determination: TSI Aerodynamics particle Sizer and a 20:1 diluter.
- Treatment of exhaust air:

TEST ATMOSPHERE
- Brief description of analytical method used:
- Samples taken from breathing zone: not specified

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

6 hours per day for a total of 19 exposures over 4 weeks

Frequency of treatment:

Five days/week for three weeks and four consecutive days during the fourth week

Dose / conc.:

0 mg/m³ air

Remarks:

Control

Dose / conc.:

147 mg/L air (analytical)

Remarks:

Test group

No. of animals per sex per dose:

15 males for the test and control group respectively

Control animals:

other: concurrent; filtered air

Details on study design:

Post-exposure period: Not applicable. The rats were observed daily during exposure and observations were recorded on a group basis. Preceding and following each exposure and on weekends, observations were recorded for animals exhibiting overt clinical signs.

Positive control:

No

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily when not exposed. When exposed, observations were recorded on a group basis.
- Cage side observations checked in table were included: no

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily when not exposed. When exposed, observations were recorded on a group basis.

BODY WEIGHT: Yes
- Time schedule for examinations: weekly including prior to to initiation of the treatment and immediately preceding sacrifice.

FOOD CONSUMPTION AND COMPOUND INTAKE: n/a

FOOD EFFICIENCY: n/a

WATER CONSUMPTION AND COMPOUND INTAKE: No

OPHTHALMOSCOPIC EXAMINATION: Not specified

HAEMATOLOGY: No

CLINICAL CHEMISTRY: No

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

OTHER: Necropsy and histopathology evaluations occurred in all animals being exposed and includes the following tissues: gross lesions, larynx, lungs, trachea, nasal turbinates and kidneys.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Statistics:

The data for continuous and parametric variables were intercompared for the exposure and control groups by use of Levene's test for homogeneity of variances and by t-tests. If Levene's test indicated homogeneous variances, the groups were compared by pooled variance t-tests. If Levene's test indicated heterogeneous variances, the groups were compared by separate variance t-test. Frequency data were compared using Fisher's exact tests. All statistical tests, except the frequency comparisons, were performed using BMDP Statistical Software. The frequency data tests are described in Biometry (Sokal and Rohlf, 1969). The probability value of p 0.05 (two-tailed) was used as the critical level of significance for all tests.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

A significantly lower body weight gain was observed in the exposed animals between the initiation week until week 3. This was considered as not treatment related since the body weights were different prior to the start of the exposure regimen. The difference in preexposure body weight was a result of randomising the animals at different times since they were received at different times. However, body weight gain for the exposure group was statistically lower than the control group during the first week of the study which was considered as treatment related. Body weight gain was comparable or greater than the control group after the first week of exposure. Specifically, body weight gain was statistically significant greater in the exposure group at the end of the 4-week exposure period.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not specified

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not specified

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not specified

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Cytoplasmic hyalinisation (mild to moderate) was observed within the olfactory mucosa of the nasal cavity and was characterised by the presence of smooth homogenous oesinophilic material within the cytoplasm. Two of the rats with laryngeal squamous metaplasia had also minimal degrees of granulomatous laryngitis. Moreover, alveolar histiocytosis, bronchopneumonia and interstitial pneumonitis were observed within the lungs.

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Foci of squamous metaplasia (minimal to mild) were present within the larynx and nasal mucosa of exposed rats. The squamous metaplasia observed in the larynx was observed in the region of the transitional epithelium which is susceptible to toxic injury. Cellular hyperplasia was observed within the trachea of exposed animals. Within the lungs, alveolar type II pneumocyte hyperplasia was observed.

Other effects:

effects observed, non-treatment-related

Description (incidence and severity):

The slightly higher mineralisation of the corneal epithelium and at the corneoscleral junction was not considered to be exposure related since these formations are common in Fischer 344 rat strain and the intergroup frequency of these lesions can vary widely.

Dose descriptor:

LOAEC

Effect level:

>= 147 mg/L air (analytical)

Based on:

test mat.

Sex:

male

Basis for effect level:

body weight and weight gain

histopathology: non-neoplastic

Critical effects observed:

not specified

Conclusions:

In a 28-day repeated inhalation study, which was conducted according to a protocol similar to OECD TG 414 and in compliance with GLP, it was reported that exposure to an aerosol of the test substance hydrolysate (147 mg/L) was associated with laryngeal changes, however, not laryngeal granulomas.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEC

0.147 mg/m³

Study duration:

subacute

Species:

rat

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988-08-08 to 1988-08 19 (in life)

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The objective of this 11-day repeated cutaneous dose toxicity study was to evaluate the potential skin irritancy and systemic toxicity of the test article in rabbit resulting from 9 applications.

GLP compliance:

yes

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:
- Females nulliparous and non-pregnant: not specified
- Age at study initiation: 18 weeks
- Weight at study initiation: 2976 to 3388 grams for males and from 2885 to 3484 grams for females.
- Fasting period before study: No
- Housing: not specified
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: not specified

Type of coverage:

occlusive

Vehicle:

other: mineral oil

Details on exposure:

The test article was administered at a constant volume of 2.0 ml/kg/day in mineral oil (1%, 5% or 7.5% solutions) and the resulting dose levels corresponded to 17, 84 and 126 mg bw/kg/day. These dose levels were chosen based upon the results of a four-day probe with the test material diluted to 1, 5, 7.5 and 10% in mineral oil. The control group was treated with mineral oil only, at the same volume. The doses were applied using the treatment regimen identified above. The animals given 126 mg/kg/day were treated with the test material at least 6 hours/day for 3 consecutive days and observed for any reversal of the cutaneous irritation for the remainder of the study. Prior to dosing and subsequently as required, the fur was clipped from the dorsal area of the trunk of each animal. The clipped area was covered with a gauze patch and the test solution was applied to the gauze patch. Each animal was then wrapped and returned to its cage for a period of 6 hours. At the end of the exposure period, the wrappings were removed and the exposure area was wiped with a dry cloth to remove any remaining test material.

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

6 h/day, 3 days or 9 days (over 11 days)

Frequency of treatment:

See table 1, below.

Animals in the 0, 17, and 84 mg/kg bw/day groups were treated for five consecutive days in the first week, followed by two days without treatment, and subsequently four consecutive days of treatment in the second week for a total of nine applications. Those in the 126 mg/kg bw/day group were treated on 3 consecutive days.

Dose / conc.:

17 mg/kg bw/day (nominal)

Dose / conc.:

84 mg/kg bw/day (nominal)

Dose / conc.:

126 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: Not applicable. All animals were euthanized and necropsied upon completion of the treatment period; no recovery or other satellite groups were included.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once daily
- Cage side observations checked in table were included: No

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once daily

DERMAL IRRITATION: Yes
- Time schedule for examinations: daily immediately before each application of the test material, on the days when no test material was applied and on the day of necropsy.

BODY WEIGHT: Yes
- Time schedule for examinations: on the first day of treatment (Day 1) and on Days 8 and 12.

FOOD CONSUMPTION: yes, daily
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data

FOOD EFFICIENCY: not specified
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION: No data
- Time schedule for examinations: n/a

OPHTHALMOSCOPIC EXAMINATION: No data
- Time schedule for examinations: n/a
- Dose groups that were examined: n/a

HAEMATOLOGY: Yes
- Time schedule for collection of blood: At study termination (day 12)
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: All animals
- Parameters checked in table were examined: Yes

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At study termination (day 12)
- Animals fasted: No data
- How many animals: All animals
- Parameters checked in table were examined: Yes

URINALYSIS: Yes
- Time schedule for collection of urine: At study termination (day 12)
- Metabolism cages used for collection of urine: No, urine was collected from the urinary bladder following anaesthesia.
- Animals fasted: No data
- Parameters checked in table were examined: Not specified

NEUROBEHAVIOURAL EXAMINATION: No
- Time schedule for examinations: n/a
- Dose groups that were examined: n/a
- Battery of functions tested: sensory activity / grip strength / motor activity / other: n/a

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table)

HISTOPATHOLOGY: Yes (see table)

Statistics:

Levene's test was done to test for variance homogeneity. In the case of heterogeneity of variance at p 0.05, transformations were used to stabilize the variance. Analysis of variance (ANOVA) was done on the homogeneous or ranked data. If the ANOVA was significant, Dunnett's t-test was used for pairwise comparison between groups. When no transformation established variance homogeneity at p 0.001, the data were also examined by nonparametric techniques. These statistics include the Kruskal-Wallis H-test ANOVA and, if this test was significant, the Nemenyi-Kruskal-Wallis test for multiple comparisons or the Wilcoxon-Mann-Whitney two-sample rank test. Standard one-way ANOVA was used to analyze initial body weights, food consumptions, clinical chemistry and hematology values (except red blood cell morphology), organ weights, organ-to-body weight percentages, and organ-to-body weight ratios. Standard one-way analysis of covariance (ANCOVA) was used to analyze body weight, with initial body weight as the covariate. Although Levene's test for variance homogeneity was done, no transformations were used because covariance adjustment removed extraneous heterogeneity. If the ANCOVA was significant, Dunnett's t-test was used for pairwise comparisons between groups.

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

In the control and the low dose group, mild erythema and desquamation resulted from treatment with mineral oil. The lesions occurred earlier in the animals in the 17 mg/kg bw/day group. Moderate to severe erythema, edema, desquamation, atonia, and fissuring developed progressively in both sexes treated with 84 mg/kg bw/day. Moderate to severe lesions were observed in the high dose group animals following the second treatment and dosing was terminated after the third treatment. A slight improvement in erythema, oedema, and atonia occurred following termination of the dosing, however, desquamation and fissuring showed no significant improvement by the end of the study. Observations related to the test article at necropsy were restricted to cutaneous lesions at the treatment site.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, non-treatment-related

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not specified

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Microscopically, the test material resulted in moderately severe local skin changes characterized by crusting, acanthosis/hyperkeratosis, and ulcerative dermatitis primarily in the mid and high dose groups

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Dose descriptor:

NOAEL

Remarks:

Application for 9 days (over 11 days)

Effect level:

84 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: No observable effects

Dose descriptor:

NOAEL

Remarks:

Application for 3 days

Effect level:

126 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: No observable effects

Dose descriptor:

LOAEL

Remarks:

local effects

Effect level:

17 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: skin irritation

Critical effects observed:

not specified

The site of contact NOAEL was less than 17 mg/kg bw/day.

Conclusions:

A generally well reported 11-day dermal study, conducted in accordance with GLP but not to a current guideline, found skin irritation but no systemic toxicity in rabbits after 9 repeated doses of 84 mg/kg bw/day or 3 repeated doses of 126 mg/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

126 mg/kg bw/day

Study duration:

subacute

Species:

rabbit

Repeated dose toxicity: dermal - local effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988-08-08 to 1988-08 19 (in life)

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The objective of this 11-day repeated cutaneous dose toxicity study was to evaluate the potential skin irritancy and systemic toxicity of the test article in rabbit resulting from 9 applications.

GLP compliance:

yes

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:
- Females nulliparous and non-pregnant: not specified
- Age at study initiation: 18 weeks
- Weight at study initiation: 2976 to 3388 grams for males and from 2885 to 3484 grams for females.
- Fasting period before study: No
- Housing: not specified
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: not specified

Type of coverage:

occlusive

Vehicle:

other: mineral oil

Details on exposure:

The test article was administered at a constant volume of 2.0 ml/kg/day in mineral oil (1%, 5% or 7.5% solutions) and the resulting dose levels corresponded to 17, 84 and 126 mg bw/kg/day. These dose levels were chosen based upon the results of a four-day probe with the test material diluted to 1, 5, 7.5 and 10% in mineral oil. The control group was treated with mineral oil only, at the same volume. The doses were applied using the treatment regimen identified above. The animals given 126 mg/kg/day were treated with the test material at least 6 hours/day for 3 consecutive days and observed for any reversal of the cutaneous irritation for the remainder of the study. Prior to dosing and subsequently as required, the fur was clipped from the dorsal area of the trunk of each animal. The clipped area was covered with a gauze patch and the test solution was applied to the gauze patch. Each animal was then wrapped and returned to its cage for a period of 6 hours. At the end of the exposure period, the wrappings were removed and the exposure area was wiped with a dry cloth to remove any remaining test material.

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

6 h/day, 3 days or 9 days (over 11 days)

Frequency of treatment:

See table 1, below.

Animals in the 0, 17, and 84 mg/kg bw/day groups were treated for five consecutive days in the first week, followed by two days without treatment, and subsequently four consecutive days of treatment in the second week for a total of nine applications. Those in the 126 mg/kg bw/day group were treated on 3 consecutive days.

Dose / conc.:

17 mg/kg bw/day (nominal)

Dose / conc.:

84 mg/kg bw/day (nominal)

Dose / conc.:

126 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: Not applicable. All animals were euthanized and necropsied upon completion of the treatment period; no recovery or other satellite groups were included.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once daily
- Cage side observations checked in table were included: No

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once daily

DERMAL IRRITATION: Yes
- Time schedule for examinations: daily immediately before each application of the test material, on the days when no test material was applied and on the day of necropsy.

BODY WEIGHT: Yes
- Time schedule for examinations: on the first day of treatment (Day 1) and on Days 8 and 12.

FOOD CONSUMPTION: yes, daily
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data

FOOD EFFICIENCY: not specified
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION: No data
- Time schedule for examinations: n/a

OPHTHALMOSCOPIC EXAMINATION: No data
- Time schedule for examinations: n/a
- Dose groups that were examined: n/a

HAEMATOLOGY: Yes
- Time schedule for collection of blood: At study termination (day 12)
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: All animals
- Parameters checked in table were examined: Yes

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At study termination (day 12)
- Animals fasted: No data
- How many animals: All animals
- Parameters checked in table were examined: Yes

URINALYSIS: Yes
- Time schedule for collection of urine: At study termination (day 12)
- Metabolism cages used for collection of urine: No, urine was collected from the urinary bladder following anaesthesia.
- Animals fasted: No data
- Parameters checked in table were examined: Not specified

NEUROBEHAVIOURAL EXAMINATION: No
- Time schedule for examinations: n/a
- Dose groups that were examined: n/a
- Battery of functions tested: sensory activity / grip strength / motor activity / other: n/a

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table)

HISTOPATHOLOGY: Yes (see table)

Statistics:

Levene's test was done to test for variance homogeneity. In the case of heterogeneity of variance at p 0.05, transformations were used to stabilize the variance. Analysis of variance (ANOVA) was done on the homogeneous or ranked data. If the ANOVA was significant, Dunnett's t-test was used for pairwise comparison between groups. When no transformation established variance homogeneity at p 0.001, the data were also examined by nonparametric techniques. These statistics include the Kruskal-Wallis H-test ANOVA and, if this test was significant, the Nemenyi-Kruskal-Wallis test for multiple comparisons or the Wilcoxon-Mann-Whitney two-sample rank test. Standard one-way ANOVA was used to analyze initial body weights, food consumptions, clinical chemistry and hematology values (except red blood cell morphology), organ weights, organ-to-body weight percentages, and organ-to-body weight ratios. Standard one-way analysis of covariance (ANCOVA) was used to analyze body weight, with initial body weight as the covariate. Although Levene's test for variance homogeneity was done, no transformations were used because covariance adjustment removed extraneous heterogeneity. If the ANCOVA was significant, Dunnett's t-test was used for pairwise comparisons between groups.

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

In the control and the low dose group, mild erythema and desquamation resulted from treatment with mineral oil. The lesions occurred earlier in the animals in the 17 mg/kg bw/day group. Moderate to severe erythema, edema, desquamation, atonia, and fissuring developed progressively in both sexes treated with 84 mg/kg bw/day. Moderate to severe lesions were observed in the high dose group animals following the second treatment and dosing was terminated after the third treatment. A slight improvement in erythema, oedema, and atonia occurred following termination of the dosing, however, desquamation and fissuring showed no significant improvement by the end of the study. Observations related to the test article at necropsy were restricted to cutaneous lesions at the treatment site.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, non-treatment-related

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not specified

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Microscopically, the test material resulted in moderately severe local skin changes characterized by crusting, acanthosis/hyperkeratosis, and ulcerative dermatitis primarily in the mid and high dose groups

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Dose descriptor:

NOAEL

Remarks:

Application for 9 days (over 11 days)

Effect level:

84 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: No observable effects

Dose descriptor:

NOAEL

Remarks:

Application for 3 days

Effect level:

126 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: No observable effects

Dose descriptor:

LOAEL

Remarks:

local effects

Effect level:

17 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: skin irritation

Critical effects observed:

not specified

The site of contact NOAEL was less than 17 mg/kg bw/day.

Conclusions:

A generally well reported 11-day dermal study, conducted in accordance with GLP but not to a current guideline, found skin irritation but no systemic toxicity in rabbits after 9 repeated doses of 84 mg/kg bw/day or 3 repeated doses of 126 mg/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEL

17 mg/cm²

Study duration:

subacute

Species:

rabbit

Additional information

In the key 90-day oral repeated dose toxicity study, the high dose of 600 mg/kg bw/day was not well tolerated by a number of animals which were terminated prior to the scheduled necropsy. The main findings at this dose were clinical signs (rales and poor clinical condition), changes in some liver enzyme values, and/or an increase in mean relative liver weights (males only) and microscopic changes of hepatocellular vacuolation in the liver (males only). Based on these findings the NOAEL was defined as the intermediate dose of 200 mg/kg bw/day (WIL, 2001). The study was conducted according to OECD Test Guideline 408 and in compliance with GLP. In a supporting 14-day oral range-finding study conducted at the same doses that preceded the 90-day study, similar clinical signs and hepatic changes were recorded (WIL, 1999).

In another supporting 14-day oral repeated dose study on the silanol hydrolysis product, 3-aminopropylsilanetriol, no effect of treatment was noted at doses up to 81 mg/kg bw/day, the highest dose tested (Shin-Etsu, 1996).

In the key 28-day repeated dose inhalation study, a concentration of 147 mg/L resulted in laryngeal changes (squamous metaplasia and foci of minimal granulomatous laryngitis) and other histopathological changes in the olfactory and nasal mucosa, trachea and lungs which indicate on a local effect (BRRC, 1991). The study was conducted according to a protocol similar to OECD Test Guideline 412 and in compliance with GLP.

The repeated dose dermal study conducted in rabbits resulted in marked skin irritation but no systemic effects after 9 doses of 84 mg/kg bw/day or 3 doses of 126 mg/kg bw/day (BRRC, 1990).

Justification for classification or non-classification

Based on the available data 3-aminopropyl(triethoxy)silane does not require classification for specific target organ toxicity following repeated exposure according to Regulation (EC) No. 1272/2008.

The non-silanol hydrolysis product is not expected to contribute to the toxicity profile of 3-aminopropyl(triethoxy)silane as generally in repeat dose studies in animals with ethanol very large doses are used, and often specific endpoints relating to known effects in humans are the primary focus of such studies. However, adverse effects on the liver have been noted in animals but only at very high doses >8 g/kg bw/day. Ethanol is not classified for repeated dose toxicity in Annex VI of Regulation (EC) No 1272/2008.