Tributyl borate

Endpoint summary

Description of key information

Tributyl borate is rapidly hydrolyzed to Boric acid and n-Butanol in the presence of water or moisture in the air (18.3 sec at 21°C). Reliable endpoint data of the hydrolysis products n-Butanol and Boric acid are used, which is entirely appropriate to draw conclusions on the acute toxicity of Tributyl borate by the oral route:

1) Hydrolysis product n-Butanol

LD50 in female rats: 2290 mg/kg bw.

2) Hydrolysis product Boric acid

- LD50 in male rats: 3450 mg/kg bw (2950 - 4040 mg/kg bw);

- LD50 in female rats 4080 mg/kg bw (3640 - 4560 mg/kg bw).

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

other: experimental study on hydrolysis product Boric acid

Adequacy of study:

key study

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards with acceptable restrictions.

Qualifier:

according to guideline

Guideline:

other: No data

Deviations:

not specified

Principles of method if other than guideline:

Boric acid was administered orally by gavage to six groups of five male and five female albino Sprague-Dawley rats. The test material was administered as a 50 % w/v suspension in 0.5 % aqueous methyl cellulose at dosage levels of 2.0; 2.5; 3.16; 3.98; 5.01 and 6.31 g/kg bw. Rats were fasted for a period of 3 to 4 h prior to dosage. Animals were observed for mortality and toxic effects at 1, 2, 4, and 24 h and once daily after for a total of 14 days. At the end of the observation period the surviving animals were weighed sacrificed and autopsies were performed.

GLP compliance:

no

Remarks:

Study pre-dates GLP

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
- Weight at study initiation: Males: 267 - 302 g; Females: 214 - 248 g

Route of administration:

oral: gavage

Vehicle:

other: 0.5 % aqueous methyl cellulose

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 50 % w/v

MAXIMUM DOSE VOLUME APPLIED: 3450 - 4080 mg/kg bw

Doses:

2.0; 2.5; 3.16; 3.98; 5.01 and 6.31 g/kg bw.

No. of animals per sex per dose:

Five animals/group; no further data

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Necropsy of survivors performed: Yes
- Other examinations performed: Clinical signs

Statistics:

Litchfield and Wilcoxon

Sex:

male

Dose descriptor:

LD50

Effect level:

3 450 mg/kg bw

Based on:

test mat.

95% CL:

2 950 - 4 040

Remarks on result:

other: mg boric acid/kg

Sex:

female

Dose descriptor:

LD50

Effect level:

4 080 mg/kg bw

Based on:

test mat.

95% CL:

3 640 - 4 560

Remarks on result:

other: mg boric acid/kg bw

Mortality:

No data

Clinical signs:

Symptoms include sings of CNS depression, ataxia, convulsions, laboured breathing or rapid respiration; blood crust around nose, marked diarrhoea and ptosis.

Body weight:

No data

Gross pathology:

Autopsies indicated congestion of lungs, kidneys and adrenals; inflammation of the pyloric portion of stomach and small intestine.

Other findings:

No data

Interpretation of results:

other: EU-GHS criteria not met

Conclusions:

The acute oral LD50 of boric acid for male albino rats was 3450 (2950 - 4040) mg boric acid/kg, equivalent to 604 mg B/kg bw. In female albino rats the acute oral LD50 of boric acid was 4080 (3640 - 4560) mg boric acid/kg, equivalent to 714 mg B/kg bw.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

other: experimental study on hydrolysis product n-Butanol

Adequacy of study:

key study

Study period:

1967

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study was conducted prior to GLP and test guidelines, but sufficient data is available for interpretation of results.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Principles of method if other than guideline:

Test material was administered by oral gavage to rats at various dose levels. Survivors were observed for 14 days after dosing.

GLP compliance:

no

Remarks:

performed prior to GLP

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

other: Harlan Wistar

Sex:

female

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Doses:

Dosage levels differ by a factor of 2 in a geometric series.

No. of animals per sex per dose:

Number of female rats used not stated in report but typically 6 rats are used/dose level.

Control animals:

no

Sex:

female

Dose descriptor:

LD50

Effect level:

2.83 mL/kg bw

Based on:

test mat.

Remarks on result:

other: original value

Sex:

female

Dose descriptor:

LD50

Effect level:

ca. 2 292 mg/kg bw

Based on:

test mat.

Remarks on result:

other: converted value (calculated with a density 0.81 g/mL)

No additional information available.

Interpretation of results:

other: EU-GHS criteria not met

Conclusions:

LD50 in female rats: 2.83 ml/kg, corresponding to 2290 mg/kg bw

Executive summary:

The acute oral toxicity of n-butanol was determined in a study comparable to OECD TG 401.

60-day-old female Harlan Wistar rats were dosed with the test material at various dose levels per gavage. The acute LD50 value was 2.83 mL/kg bw in female rats, corresponding to 2290 mg/kg bw (calculated with a density of 0.81 g/mL). No further data were available.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The hydrolysis product boric acid does not require classification for lethal effects following single oral exposure according to Regulation 1272/2008/EC.

The hydrolysis product n-Butanol is listed in Annex VI to Regulation (EC) No 1272/2008 and classified with Cat. 4 oral (H302:" Harmful if swallowed"). As the classification in the Annex shall be considered as a minimum classification, the target substance Tributyl borate is classified in this hazard class as well.