Tris(2-ethylhexyl) orthoborate

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 September 2003 to 08 December 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Details on test material:

- Physical state: Colourless liquid
- Date received: 20 December 2002
- Storage condition of test material: Room temperature in the dark, over silica gel, under nitrogen

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

ANIMALS AND ANIMAL HUSBANDARY
- Female Sprague-Dawley CD (Crl: CD (SD) IGS BR) strain rats were supplied by Charles River (UK) Ltd, Margate, Kent, UK.
- The animals were randomly allocated to cages on receipt.
- The animals were nulliparous and non-pregnant.
- After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink marking on the tail and a number written on the cage card.
- At the start of the study the animals were eight to twelve weeks of age.
- The bodyweights fell within an interval of ± 20 % of the mean initial bodyweight of the first treated group.
- Animals were housed in groups of three in suspended solid-floor polypropylene cages furnished with wood flakes.
- With the exception of an overnight fast immediately before dosing and for approximately three to four hours after dosing, free access to mains drinking water and food (Certified Rat and Mouse Diet (Code 5LF2) supplied by International Product Supplies Limited, Wellingborough, Northants, UK) was allowed throughout the study.
- The diet, drinking water and bedding were routinely analysed and were considered not to contain any contaminants that would reasonably be expected to affect the purpose or integrity of the study.
- Temperature and relative humidity were set to achieve limits of 19 °C to 25 °C and 30 % to 70 % respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study.
- The rate of air exchange was at least 15 changes per hour.
- Lighting was controlled by a time switch to give 12 hours continuous light (06:00 to 18:00) and 12 hours darkness.
- Animals were provided with environmental enrichment items, which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Two groups of three female animals

Control animals:

no

Details on study design:

PROCEDURE
- Using all available information on the toxicity of the test material, 2000 mg/kg bw was chosen as the starting dose.
- All animals were dosed once only by gavage, using a metal cannula attached to a graduated syringe.
- The volume administered to each animal was calculated according to the fasted bodyweight at the time of dosing.
- Treatment of animals was sequential.
- Sufficient time was allowed between each group to confirm the survival of the previously dosed animals.
- Animals were observed for deaths or overt signs of toxicity 0.5, 1, 2 and 4 hours after dosing and subsequently once daily for up to 14 days.
- Individual bodyweights were recorded prior to dosing and 7 and 14 days after treatment or at death.
- At the end of the observation period the surviving animals were killed by cervical dislocation.
- All animals were subjected to gross pathological examination. This consisted of an external examination and opening of the abdominal and thoracic cavities for examination of major organs. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

EVALUATION OF DATA
- Data evaluations included the relationship, if any, between the exposure of the animal to the test material and the incidence and severity of all abnormalities including behavioural and clinical observations, gross lesions, bodyweight changes, mortality and any other toxicological effects.
- Using the mortality data obtained, an estimate of the acute oral median lethal dose (LD50) of the test material was made as shown in the schematic diagram in Appendix 1 (attached).

Results and discussion

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

- Individual mortality data are given in Table 1 (attached).
- One animal was found dead one day after dosing.

Clinical signs:

other: - Individual clinical observations are given in Table 2 (attached). - Signs of systemic toxicity noted during the study were hunched posture, ataxia, lethargy, pilo-erection, diuresis, decreased respiratory rate and laboured respiration. Surviving animals

Gross pathology:

- Individual necropsy findings are given in Table 4 (attached).
- Abnormalities noted at necropsy of the animal that died during the study were abnormally red lungs, dark liver and dark kidneys. No abnormalities were noted at necropsy of animals that were killed at the end of the study.

Applicant's summary and conclusion

Conclusions:

The acute oral median lethal dose (LD50) of the test material in the female Sprague-Dawley CD strain rat was estimated as being greater than 2000 mg/kg bw.

Executive summary:

INTRODUCTION

The study was performed to assess the acute oral toxicity of the test material following a single oral administration in the Sprague-Dawley CD strain rat. The method was designed to meet the requirements of the OECD Guidelines for the testing of Chemicals No 423 "Acute Oral Toxicity - Acute Toxic Class Method" (adopted 17 December 2001).

METHOD

A group of three fasted females was treated with the test material at a dose level of 2000 mg/kg bw. This was followed by a further group of three fasted females at the same dose level.

The test material was administered orally undiluted. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Mortality: One animal was found dead the day after dosing.

Clinical observations: Signs of systemic toxicity noted during the study were hunched posture, ataxia, lethargy, pilo-erection, diuresis, decreased respiratory rate and laboured respiration. Surviving animals appeared normal two or three days after dosing.

Body weight: The surviving animals showed expected gains in body weight over the study period.

Necropsy: Abnormalities noted at necropsy of the animal that died during the study were abnormally red lungs, dark liver and dark kidneys. No abnormalities were noted at necropsy of animals that were killed at the end of the study.

CONCLUSION

The acute oral median lethal dose (LD50) of the test material in the female Sprague-Dawley CD strain rat was estimated as being greater than 2000 mg/kg bw.