Trimethoxysilane

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The study was conducted according to an appropriate OECD test guideline, with acceptable restrictions. The restrictions were there was no GLP statement or information on the test substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

Limited details on the test substance, no information on GLP status.

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Trimethoxysilane

EC Number:

219-637-2

EC Name:

Trimethoxysilane

Cas Number:

2487-90-3

Molecular formula:

C3H10O3Si

IUPAC Name:

Trimethoxysilane

Test material form:

liquid

Test animals

Species:

rat

Strain:

not specified

Sex:

male/female

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Doses:

males: 1.0, 2.0, 4.0, and 8.0 ml/kg; females: 1.0, 1.41, 2.0, and 4.0 ml/kg

No. of animals per sex per dose:

5/sex/dose, with the exception of only 2 male rats dosed at 8.0 ml/kg

Control animals:

no

Details on study design:

The test material was administered orally by gavage to four groups of rats (5/sex/dose, with the exception of only 2 male rats dosed at 8.0 ml/kg).
The animals were observed for mortality and toxic effects immediately after dosing and daily for a total of 14 days.  At the end of the 14 day observation period the surviving animals were weighed, sacrificed and necropsied.  Animals that died during the study were also subjected to a necropsy.

Results and discussion

Effect levels

Effect levels 1

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

2.46 mL/kg bw

95% CL:

>= 1.79 - <= 3.39

Remarks on result:

other: Equivalent to 2337 mg/kg bw based on a density of 0.95

Effect levels 2

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

1.56 mL/kg bw

95% CL:

>= 1.33 - <= 1.83

Remarks on result:

other: Equivalent to 1482 mg/kg bw based on a density of 0.95

Mortality:

Most deaths occurred at one to 4 days.  Three females died at 7 to 11 days.  Most survivors recovered at 2 days with one male rat recovering at 10 days.

Clinical signs:

other: Signs of toxicity included sluggishness, lacrimation, an unsteady gait, distended abdomens (a "bloated" appearance), head and body twitches (in 2), piloerection, prostration, a moribund appearance (in one), red crust around nose and eyes, diarrhea (in 2),

Gross pathology:

 At necropsy, there were gas-filled stomachs and intestines, red and/or thick stomachs (glandular portion), a hard white material present in the stomach, red intestines and red liquid-filled abdominal cavities.  These observations were noted only for animals that died.  The only gross pathologic finding for survivors was a mottled and tan to dark red appearance of several kidneys.

Other findings:

MALES:
Dosage (ml/kg): 8.0
Dead/Dosed: 2/2
Days to Death: 1, 1
Mean Weight, g +/- S.D.: 0 days: 249 +/- 4.2 7 days: - 14 days: 
Signs of Toxicity: Marked sluggishness at 10 min; distended abdomens, prostration, head and body twitches at 45 min.
Gross Pathology: Glandular portion of stomachs red, thick; stomachs severely distended with gas and a hard material; intestines red, gas-filled; abdominal cavities filled with red liquid.

Dosage (ml/kg): 4.0
Dead/Dosed: 5/5
Days to Death: 1, 1, 1, 4, 4
Mean Weight, g +/- S.D.: 0 days: 221 +/- 12.8 7 days: - 14 days: 
Signs of Toxicity: Sluggishness at 10 min; distended abdomen at 1 hr; lacrimation at 2 hr; red crust on perinasal fur at 1 day; red crust on periocular fur of 1 at 2 days.
Gross Pathology: Glandular portion of stomachs red, thick; stomachs severely distended with gas and a hard white material; intestines red, gas-filled; abdominal cavity of 1 filled with red liquid.

Dosage (ml/kg): 2.0
Dead/Dosed: 1/5
Days to Death: 1
Mean Weight, g +/- S.D.: 0 days: 207 +/- 6.2 7 days: 209 +/- 27.0 14 days: 242 +/ 27.1
Signs of Toxicity: Marked sluggishness, unsteady gait at 30 min; distended abdomen at 1.5 hr, red crust on perinasal fur at 1 day; emaciation of 1 at 7 days.  Survivors recovered at 2 to 10 days.
Gross Pathology: In animal that died, glandular portion of stomach red, thick; stomach distended with gas and a hard material; intestines red, gas-filled.  In survivors, nothing remarkable.

Dosage (ml/kg): 1.0
Dead/Dosed: 0/5
Days to Death: -
Mean Weight, g +/- S.D.: 0 days: 223 +/- 13.4 7 days: 262 +/- 15.8 14 days: 293 +/ 20.1
Signs of Toxicity: None noted.
Gross Pathology: Kidneys of 2 mottled tan to dark red.

FEMALES:
Dosage (ml/kg): 4.0
Dead/Dosed: 5/5
Days to Death: 2, 2, 2, 2, 9
Mean Weight, g +/- S.D.: 0 days: 222 +/- 8.8 7 days: 166 14 days: -
Signs of Toxicity: Sluggishness, unsteady gait at 15 min; distended abdomens, lacrimation at 30 min; prostration at 1 hr; red crust on perinasal fur at 1 day; unkempt appearance in 1 at 2 days; emaciation in 1 at 6 days.
Gross Pathology: Glandular portion of stomachs red, thick; stomachs distended with gas and a hard material; intestines red, gas-filled.
Dosage (ml/kg): 2.0
Dead/Dosed: 5/5
Days to Death: 1, 1, 2, 7, 11
Mean Weight, g +/- S.D.: 0 days: 211 +/- 7.9 7 days: 182 14 days: 
Signs of Toxicity: Makred sluggishness; lacrimation, distended abdomens at 1.5 hr; prostration followed by a moribund appearance in 1 at 1 day; red discharge on perinasal fur at 1 day; red crust on periocular fur at 2 days; emaciation in 2 at 5 days.
Gross Pathology: Glandular portion of stomachs red, thick; stomachs distended with gas; stomachs of 2 with a hard white material; intestines red, gas-filled.

Dosage (ml/kg): 1.41
Dead/Dosed: 1/5
Days to Death: 2
Mean Weight, g +/- S.D.: 0 days: 221 +/- 8.2 7 days: 234 +/- 9.4 14 days: 249 +/ 6.8
Signs of Toxicity: Sluggishness, lacrimation, distended abdomen, piloerection at 4 hr; diarrhea in 2 at 4 hr; prostration in 1 at 1 day; unkempt appearance at 1 day. Survivors recovered at 2 days.
Gross Pathology: In animals that died, glandular portion of stomach red, thick; stomach distended with gas and a hard white material.  In survivors, nothing remarkable.

Dosage (ml/kg): 1.0
Dead/Dosed: 0/5
Days to Death: -
Mean Weight, g +/- S.D.: 0 days: 210 +/- 3.0 7 days: 225 +/- 2.7 14 days: 238 +/ 4.9
Signs of Toxicity: None noted.
Gross Pathology: Kidneys mottled tan to dark red.

Any other information on results incl. tables

Table 1 Summary of mortality and body weight data

Dead/number in group	Days to death	Mean weight (g) ± standard deviation
		0 days	7 days	14 days
Males
2/2	1,1	249± 4.2	-	-
5/5	1,1,1,4,4	221± 12.8	-	-
1/5	1	207± 6.2	209± 27	242± 27.1
0/5	-	223± 13.4	262± 15.8	293± 20.1
Females
5/5	2,2,2,2,9	222± 8.8	166	-
5/5	1,1,2,7,11	211± 7.9	182	-
1/5	2	221± 8.2	234± 9.4	249± 6.8
0/5	-	210± 3.0	225± 2.7	238± 4.9

Signs of toxicity included sluggishness, lacrimation, unsteady gait, distended abdomen, head and body twitches (two animals), piloerection, prostration, moribund appearance (one animal), red crust around nose and eyes, diarrhoea (two animals), inkempt appearance and emaciation. Most deaths occurred between one and four days after administration. At necrospy the animals that died had gas-filled stomachs and intestines, red and/or thick stomachs, a hard white material in the stomach, red intestines and red liquid-filled abdominal cavities. In survivors, the only macroscopic finding was mottled and tan to dark red appearance of several kidneys.

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

In an acute oral toxicity study, conducted according to a protocol similar to the now deleted OECD Test Guideline 401, the LD50 for trimethoxysilane was 2.46 mL/kg bw (ca. 2337 mg/kg bw) for males rats and 1.56 mL/kg bw (ca 1482 mg/kg bw) for female rats.

Executive summary:

In an acute oral toxicity study (reliability score 2) the LD50 for trimethoxysilane was 2.46 and 1.56 ml/kg bw for males and females, respectively. Signs of toxicity included sluggishness, lacrimation, unsteady gait, distended abdomen, head and body twitches (two animals), piloerection, prostration, moribund appearance (one animal), red crust around nose and eyes, diarrhoea (two animals), inkempt appearance and emaciation. Most deaths occurred between one and four days after administration. At necrospy the animals that died had gas-filled stomachs and intestines, red and/or thick stomachs, a hard white material in the stomach, red intestines and red liquid-filled abdominal cavities. In survivors, the only macroscopic finding was mottled and tan to dark red appearance of several kidneys. There was no apparent effect on body weights.