Registration Dossier

Administrative data

Description of key information

The key acute oral toxicity study (BRRC, 1984) reported LD50 values of 7120 and 7236 mg/kg bw for males and females respectively, in a study conducted according to current guideline but not in compliance with GLP. The key acute inhalation study (BRRC, 1986) reported an LC50 of 2773 ppm (16.8 mg/l) for male and female rats in a study conducted according to current guideline, but not in compliance with GLP. The key acute dermal toxicity study (BRRC 1984) reports LD50 values of 3.36 ml/kg bw and 4.0 ml/kg bw in female and male rabbits respectively (estimated to be equivalent to 3259 and 3880 mg/kg bw) in a study conducted according to current guideline but not in compliance with GLP.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
7 120 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LC50
Value:
16 800 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
3 259 mg/kg bw

Additional information

The key acute oral toxicity study (BRRC, 1984) gave LD50 values of 7.34 ml/kg bw and 7.46 ml/kg bw in male and female rats, respectively. Clinical signs included sluggishness, red to brown discharge, lacrimation, pilo-erection, unkempt appearance, prostration, emaciation and unsteady gait. At necropsy, dark red kidney sections were observed in animals that died at 16 and 8 ml/kg bw. There were no gross necropsy findings in animals that survived to the end of the study. On the basis of a measured relative density of 0.97, the reported LD50 values correspond to ca. 7120 and 7236 mg/kg bw for males and females respectively.

Several supporting studies were also available for acute oral toxicity.

An LD50 value of 11.3 ml/kg bw (equivalent to 10961 mg/kg bw) was determined in a reliable study conducted according to an appropriate test protocol. The study was not compliant with GLP (Mellon 1962).

An acute oral toxicity study conducted in accordance with OECD 423 (acute toxic class method) determined the LD50 value to be between 300 and 2000 mg/kg bw (Hashima, undated). Based on weight of evidence from several other available acute oral toxicity studies which report LD50s well above the limit dose, the result of this study is considered not to be representative of the acute toxicity of the test material.

The LD50 value of 8.2 ml/kg bw (equivalent to 7954 mg/kg bw) was determined in a reliable study conducted according to an appropriate test protocol. The study was not compliant with GLP (Consultox 1976).

In addition, two reliability 4 sources were also available which are in line with the results of the reliable studies (Smyth et al., 1969, Dow Corning Corporation 1973).

 

The key acute inhalation study (BRRC, 1986) gave an LC50 of 2773 ppm (16.8 mg/l) for male and female rats. Clinical signs included perinasal, encrustation, unkempt fur, hypoactivity, blepharospasm, lacrimation, respiratory difficulties (mouth breathing, audible respiration, decreased respiration rate), ataxia, prostration, tremors, distended stomachs, a negative surface and air righting reflex, and negative toe and tail pinch reflex. Two males and four females of the 5372 ppm exposure group had eye opacities with three males and five females also having gas-filled stomachs. There were no other gross lesions in any of the other exposure groups.

 

Two reliability 4 studies were also available which support the key findings (Dow Corning Corporation 1973, BRRC 1984).

 

The key acute dermal toxicity study was conducted in accordance with an appropriate OECD test guideline, but was not compliant with GLP (BRRC, 1984). The acute dermal LD50 values were determined to be 3.36 ml/kg bw and 4.0 ml/kg bw in female and male rabbits respectively (equivalent to 3259 - 3880 mg/kg bw based on relative density of 0.97). Signs of local dermal irritation were reported, and clinical signs of toxicity included discomfort, sluggishness, unsteady gait and prostration. At necropsy, lungs were red and mottled, and some livers were mottled with hard red of white foci.

An acute dermal LD50 value of 3.54 ml/kg bw (equivalent to 3434 mg/kg bw) was determined for rabbits in a study which did not meet current guideline requirements for OECD and which was not in compliant with GLP) (Mellon 1962).

A reliability 4 study was also available (Witco 1996), which supports the key findings.


Justification for classification or non-classification

Based on the available data trimethoxyvinylsilane requires classification for acute inhalation toxicity as Acute Toxicity Category 4 (vapour); H332: Harmful if inhaled, according to Regulation (EC) 1272/2008. Classification for acute oral and dermal toxicity is not required.