Dibutyltin dilaurate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 24 June 2010 and 08 July 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in compliance with GLP and in line with the OECD guideline 402 (and EU Method B.3) with minor or no deviations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

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 (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyltin dilaurate

EC Number:

201-039-8

EC Name:

Dibutyltin dilaurate

Cas Number:

77-58-7

Molecular formula:

C32H64O4Sn

IUPAC Name:

dibutyltin dilaurate

Details on test material:

Sponsor's identification : CAS No 77-58-7
Description : clear colourless liquid
Batch number : LA6K05N001
Date received : 26 March 2010
Expiry date : 26 March 2011
Storage conditions : approximately 4°C in the dark, under nitrogen
The integrity of supplied data relating to the identity, purity and stability of the test material is the responsibility of the Sponsor.

Test animals

Species:

rat

Strain:

other: Wistar (HsdRccHan:WIST)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories U.K. Ltd., Oxon, UK
- Age at study initiation: eight to twelve weeks
- Weight at study initiation: at least 200 g (the weight variation did not exceed ± 20% of the mean weight for each sex)
- Housing: The animals were housed in suspended solid-floor polypropylene cages furnished with woodflakes. The animals were housed individually during the 24 hour exposure period and in groups of five by sex for the remainer of the study.
- Diet : Free access to 2014 Teklad Global Rodent diet supplied by Harlan Laboratories U.K. Ltd., Oxon, UK
- Water : Free access to mains drinking water
- Acclimation period: At least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 °C
- Humidity (%): 30-70%
- Air changes (per hr): The rate of air exchange was at least fifteen changes per hour
- Photoperiod (hrs dark / hrs light): Lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.

The 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.
The diet, drinking water and bedding were routinely analysed and were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: Back and flanks
- % coverage: Approximately 10%
- Type of wrap if used: A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self adhesive bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): 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.
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied : 2000 mg/kg, dose volume 1.91 mL/kg

On the day before treatment the back and flanks of each animal were clipped free of hair.
For the purpose of the study the test material was used as supplied. The specific gravity was determined and used to calculate the appropriate dose volume for the required dose level.
The absorption of the test material was not determined.

Duration of exposure:

24 hours

Doses:

2000 mg/kg

No. of animals per sex per dose:

10 (5 males/5 females)

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The animals were observed for deaths or overt signs of toxicity 30 minutes, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days. Individual bodyweights were recorded prior to application of the test material on Day 0 and on Days 7 and 14 or at death.
- Necropsy of survivors performed: Yes. At the end of the study the surviving 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.
- Other examinations performed: After removal of the dressings and subsequently once daily for fourteen days, the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize J H (1977) "Dermal and Eye Toxicity Tests" In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.31

EVALUATION OF SKIN REACTIONS
Erythema and Eschar Formation
No erythema : 0
Very slight erythema (barely perceptible): 1
Well-defined erythema: 2
Moderate to severe erythema: 3
Severe erythema (beef redness) to slight eschar formation (injuries in depth): 4
Oedema Formation
No oedema: 0
Very slight oedema (barely perceptible): 1
Slight oedema (edges of area well-defined by definite raising): 2
Moderate oedema (raised approximately 1 millimetre): 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure): 4

Any other skin reactions, if present were also recorded.

Statistics:

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 dermal median lethal dose (LD50) of the test material was made.

Results and discussion

Preliminary study:

No preliminary study reported. Dosing was selected using available information on the toxicity of the test material.

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

One female was killed for humane reasons seven days after dosing, due to the approach of the moderate severity limit set by the UK Home Office.

Clinical signs:

other: Signs of systemic toxicity noted in the female that was humanely killed were hunched posture, pilo-erection, dehydration, emaciation and pallor of the extremities. Tiptoe gait and/or hunched posture were noted in two other females. No signs of systemic

Gross pathology:

Gaseous distension of the stomach was noted in the animal that was killed for humane reasons during the study. No abnormalities were noted at necropsy of the animals killed at the end of the study.

Other findings:

Signs of dermal irritation noted were very slight erythema, light brown discolouration of the epidermis, blanching of the skin, small superficial scattered scabs, hardened light brown coloured scab, hardened dark brown/black coloured scab, scab cracking, scab lifting at edges to reveal dried blood, scab lifting to reveal glossy skin, scab undulating and glossy skin. The scab/damaged tissue at the test site of one animal has sloughed off revealing a crater (ulcer) over the majority of the test site.
Adverse dermal reactions prevented accurate evaluation of erythema and oedema at all test sites during the test. The reactions were considered to be indicative of dermal corrosion.

Any other information on results incl. tables

Tabulated data, clinical observations, necropsy data, bodyweight (and bodyweight changes) and dermal reactions are presented in the attached pdf (Tables 1 -5.pdf).

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: OECD GHS

Conclusions:

The acute dermal median lethal dose (LD50) of the test material in the Wistar strain rat was found to be greater than 2000 mg/kg bodyweight.

Executive summary:

In a GLP compliant study conducted according to OECD guideline 402, the acute dermal LD50 of the test material was determined in the Wistar rats. The acute dermal median lethal dose (LD50) of the test material in the Wistar strain rat was found to be greater than 2000 mg/kg bodyweight.