Tris(2-ethylhexyl) orthoborate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 October 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

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

GLP compliance:

yes

Test type:

standard acute 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:

male/female

Details on test animals or test system and environmental conditions:

ANIMALS AND ANIMAL HUSBANDARY
- Five male and five 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 weighed at least 200 g and were eight to twelve weeks of age.
- Animals were housed in suspended solid-floor polypropylene cages furnished with wood flakes.
- The animals were housed individually during the 24 hour exposure period and in groups of up to four, by sex, for the remainder of the study.
- 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

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

PROCEDURE
- On the day before treatment, the back and flanks of each animal were clipped free of hair.
- Initially, one male and one female rat were treated with 2000 mg/kg bw (specific gravity of test material 0.857; dose volume 2.34 mL/kg)
- The animals were caged individually during the 24 hour exposure period and for the remainder of the study.
- The calculated volume of test material, as received, was applied as evenly as possible to an area of shorn skin (approximately 10 % of the total body surface area) using a graduated syringe.
- A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self-adhesive bandage.
- Shortly after dosing the dressings were examined to ensure they were securely in place.
- After the 24hour contact period, the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test material.
- Since no mortalities were noted, a further group of animals (four males and four females) was similarly treated with the test material at a dose level of 2000 mg/kg bw.
- After the 24hour contact period, the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test material.
- The animals were returned to group housing for the remainder of the study period.
- Animals were observed for deaths or overt signs of toxicity 0.5, 1, 2 and 4 hours after dosing and subsequently once daily for 14 days.
- After removal of the dressings and subsequently once daily for 14 days, the test sites were examined for evidence of primary irritation and scored according to the Draize (1977) scale (details attached). Any other skin reactions, if present, were also noted.
- Individual bodyweights were recorded prior to application of the test material on Day 0 and on Days 7 and 14.
- At the end of the study the animals were killed by cervical dislocation.
- All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Five males and five females

Control animals:

no

Details on study design:

PREPARATION OF TEST MATERIAL
- The specific gravity was determined and used to calculate the appropriate dose volume for the required dose level.
- Absorption of the test material was not determined.

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.

Results and discussion

Effect levels

Sex:

male/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).
- There were no deaths.

Clinical signs:

other: - Individual clinical observations are given in Table 2 (attached). - There were no signs of systemic toxicity.

Gross pathology:

- Individual necropsy findings are given in Table 5 (attached).
- No abnormalities were noted at necropsy.

Other findings:

DERMAL REACTIONS
- Individual dermal reactions are given in Tables 2 and 3 (attached).
- There were no signs of dermal irritation.

Applicant's summary and conclusion

Conclusions:

The acute dermal median lethal dose (LD50) of the test material in the Sprague-Dawley CD strain rat was found to be greater than 2000 mg/kg bw.

Executive summary:

INTRODUCTION

The study was performed to assess the acute dermal toxicity of the test material 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 402 "Acute Dermal Toxicity" (adopted 24 February 1987) and Commission Directive 92/69/EEC Method B.3 Acute Toxicity (Dermal).

METHOD

Initially, two animals (one male and one female) were given a single, 24 hour, semi-occluded dermal application of the undiluted test material to intact skin at a dose level of 2000 mg/kg bw. Based on the results of the initial test, a further group of eight animals (four males and four females) were similarly treated. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

RESULTS

Mortality: There were no deaths.

Clinical Observations: There were no signs of systemic toxicity.

Dermal irritation: There were no signs of dermal irritation.

Bodyweight: All animals showed expected gains in bodyweight over the study period.

Necropsy: No abnormalities were noted at necropsy.

CONCLUSION

The acute dermal median lethal dose (LD50) of the test material in the Sprague-Dawley CD strain rat was found to be greater than 2000 mg/kg bw.