Ethanol, 2-methoxy-, manufacture of, by-products from, esters with boric acid

Endpoint summary

Description of key information

B-TTEGME in brake fluids was very well tolerated in rats after both acute oral and dermal dosing. Oral LD50 values were above the limit dose of 2000 mg/kg bw for B-TTEGME, whereas dermal LD50 values were above 1520 mg/kg bw . As also brake fluid and B-TEGME (component and read across compound) demonstrated LD50 values above 2000 mg/kg bw for oral and dermal acute toxicity, the acute safety profile of B-TTEGME is considered to be very safe. 

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Additional information

The acute toxicity of B-TTEGME was studied by read-across from data on various test materials, including Brake Fluid DOT4 Super, Brake Fluid DOT 4 and B-TEGME. Similarity with B-TTEGME was based on a common functional group, common precursors an/or likelihood of common breakdown products and common constituents, as also described in a separated justification document in Section 13.

The key study for acute oral toxicity in rats was performed with abrake fluid containing 76% B-TTEGME of which ca. 45% was B-TEGME corresponding with 37% B-TEGME in the tested brake fluid (Shell, 1990a). This study was conducted according OECD 401 guidelines and was considered to be adequate, reliable and relevant. The acute oral LD50 was greater than 5000 mg brake fluid/kg bw or greater than 3800 mg B-TTEGME/kg bw. The sole common sign of reaction to treatment was a hunched posture apparent from within 1 hour of dosing. Other isolated clinical signs were lachrymation, abasia, lethargy, unkempt appearance and encrustation of the periorbital zone. Recovery was complete by day 3. No macroscopic changes were apparent during necropsy of the treated rats on day 15.Weight of evidencewas also available from  undiluted B-TEGME (Clariant, 1995; BASF, 1974a), yielding an LD₅₀of >2000 mg/kg and of approximately 12000 mg/kg body weight, respectively. In the first study, there were no clinical signs nor macaroscopic findings; in the second study principal clinical signs were dyspnoe, slight apathy, ataxia, slight dehydration and macroscopic changes were acute hart dilatation with hyperaemia.

Acute oral toxicity was also tested in a supporting study in rats with abrake fluid, containing 38% B-TTEGME (of which ca. 45% was B-TEGME coresponding with 17% B-TEGME in the tested brake fluid) and demonstrated an LD50 value of greater than 5000 mg brake fluid/kg bw or greater than 1900 mg B-TTEGME/kg bw (Shell, 1992a). Principal signs of reaction were abasia/ataxia, hunched posture, piloerection, lachrymation and, at a later stage, unkempt appearance and staining/soiling of the anogenital fur. Recovery was advanced by day 2 and complete by Day 8 and no macroscopic changes nor deaths were apparent on day 15.Most likely other components of brake fluids may have contributed to the clinical signs observed in the animals. There were 2 other studies with brake fluid, confirming high LD50 values >4000 mg/kg bw (Shell, 1975 & 1977).

In conclusion, the acute oral toxicity profile for B-TTEGME is very safe, with LD50 values above 2000 mg/kg bw.

An acute inhalation toxicity study with B-TEGME (Inhalation Risk Test, IRT) could not be used for assessment because of significant methodological deficiencies (substance weight increase instead of decrease during IRT, probably due to hygroscopic properties of the test substance. Therefore one can not be sure whether the animals were exposed to any test substance at all. (BASF, 1974). Further inhalation toxicity testing was waived based upon a low vapour pressure.

The key study for acute dermal toxicity was based upon testing in rats with a brake fluid containing 76% B-TTEGME of which 45% was B-TEGME (Shell, 1990b). This study was applied according to OECD402 and EU B.2 method and was considered to be adequate, reliable and relevant. This study revealed an LD₅₀value greater than 2000 mg/kg body weight, corresponding to an LD₅₀>1520 mg/kg bw for B-TTEGME. Weight of evidencewas also available from an acute dermal toxicity study in rats with B-TEGME, showing an acute dermal LD₅₀value greater than 2000 mg/kg bw (Shell, 2010a).

Acute dermal toxicity was also tested in supporting studies with brake fluid,containing 38% B-TTEGME in rats (Shell, 1992b). The study showed an LD50 >2000 mg/kg bw, corresponding to >760 mg/kg bw B-TTEGME. There were no clinical signs nor any effects on body weight nor macroscopic changes, except for some minor vascular congestion of the dermis underlying the site of application. Other constituents may have contributed to these effects. There were 2 other studies with brake fluid, confirming high LD50 values >4000 mg/kg bw (Shell, 1975 & 1977).

In conclusion, based on the key study and the similarity between B-TTEGME and B-TEGME, the acute dermal toxicity profile for B-TTEGME is very safe, with LD50 values above 2000 mg/kg bw.

 

Justification for classification or non-classification

Both for oral and dermal acute toxicity testing, the acute toxicity profile was considered to be very safe. Therefore classification is not warranted.