Dibutoxydibutylstannane

Endpoint summary

Description of key information

Oral:
Sanders, A 2010; ACUTE ORAL TOXICITY IN THE RAT - FIXED DOSE METHOD; Testing Laboratory: Harlan Laboratories Limited, Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Owner company: Chemtura Corporation, 199 Benson Road, Middlebury, CONNECTICUT 06749, UNITED STATES OF AMERICA. Project No.: 3103/0038.
The acute oral median lethal dose (LD50) of the test material in the female Wistar strain rat was estimated to be greater than 2000 mg/kg bodyweight (OECD 420).
Dermal:
Sanders, A 2010; ACUTE DERMAL TOXICITY (LIMIT TEST) IN THE RAT; Testing Laboratory: Harlan Laboratories Limited, Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Owner company: Chemtura Corporation, 199 Benson Road, Middlebury, CONNECTICUT 06749, UNITED STATES OF AMERICA. Project No.: 41003850.
The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat could not be deterimined as no animals died from dermal toxicity at the tested does, however due to severe/corrosive dermal reactions the animals were killed for humane reasons at 7 days.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 05 August 2010 and 26 August 2010.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted to GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

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 of age
- Weight at study initiation: 168-188g
- Fasting period before study: overnight fast immediately before dosing and for approximately three to four hours after dosing.
- Housing: The animals were housed in groups of up to four in suspended solid floor polypropylene cages furnished with woodflakes.
- Diet/water (e.g. ad libitum): 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 (2014 Teklad Global Rodent diet supplied by Harlan Laboratories U.K. Ltd., Oxon, 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.
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25°C
- Humidity (%): 30 to 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.

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

VEHICLE
- Justification for choice of vehicle: Arachis oil BP was used because the test material did not dissolve/suspend in distilled water.

DOSAGE PREPARATION (if unusual):
For the purpose of the 2000 mg/kg dose level, 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. For the purpose of the 300 mg/kg dose level, the test material was freshly prepared, as required, as a solution in arachis oil BP.

The test material was formulated within two hours of being applied to the test system. It is assumed that the formulation was stable for this duration.
No analysis was conducted to determine the homogeneity, concentration or stability of the test material formulation. This is an exception with regard to GLP and has been reflected in the GLP compliance statement.

Doses:

300 & 2000 mg/kg

No. of animals per sex per dose:

1 female for the 300 mg/kg dose
5 females for the 2000 mg/kg dose

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Clinical observations were made ½, 1, 2, and 4 hours after dosing and then daily for fourteen days. Morbidity and mortality checks were made twice daily. Individual bodyweights were recorded on Day 0 (the day of dosing) and on Days 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: At the end of the observation period 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.

Statistics:

Data evaluations included the relationship, if any, between the animals' exposure 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. If possible the signs of evident toxicity were also identified. Evident toxicity is defined as the toxic effects which are of a severity such that administration at the next highest level could result in mortality.
Using the mortality data obtained, an estimate of the acute oral median lethal dose (LD50) of the test material was made.

Preliminary study:

Results for 300 mg/kg dose level:

There was no mortality.

Clinical Observations: No signs of systemic toxicity were noted during the observation period.

The animal showed expected gains in bodyweight over the observation period.

No abnormalities were noted at necropsy.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

One animal was found dead seven days after dosing.

Clinical signs:

other: Signs of systemic toxicity noted were hunched posture, diarrhoea, diuresis, pilo erection, emaciation and dehydration. Surviving animals appeared normal ten to thirteen days after dosing.

Gross pathology:

Dark liver and pale kidneys were noted at necropsy of the animal that died during the study but the stomach could not be examined as the animal was cannibalised. Pale liver was noted at necropsy of one animal that was killed at the end of the study. No abnormalities were noted at necropsy of all other animals that were killed at the end of the study.

Table 4              Individual Clinical Observations and Mortality Data - 2000 mg/kg

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Dosing (Hours)				Effects Noted During Period After Dosing (Days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	2-0 Female	0	0	H	H	0	0	0	0	0	0	0	DDu	DDu	DDu	0	0	0	0
	3-0 Female	0	0	0	0	0	0	0	0	0*	HPDDu	HPDDu	HEmD	HDh	0	0	0	0	0
	3-1 Female	0	0	0	0	0	0	0	0	0*	HPDDu	X
	3-2 Female	0	0	0	0	0	0	0	0	0*	HPDDh	HPDDh	HEmDh	HDh	H	H	0	0	0
	3-3 Female	0	0	0	0	0	0	0	0	0*	HPDDu	HPDh	HEmDh	HDh	H	H	H	0	0

0 = No signs of systemic toxicity

H = Hunched posture

D = Diarrhoea

Du = Diuresis

P = Pilo-erection

Em = Emaciation

Dh = Dehydration

X = Animal dead

* = Diarrhoea and diuresis noted (pm) after Day 5 observation performed

Table 5              Individual Bodyweights and Bodyweight Changes - 2000mg/kg

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			Bodyweight (g) at Death	Bodyweight Gain (g) During Week
		0	7	14		1	2
2000	2-0 Female	188	188	194		0	6
	3-0 Female	187	145	180		-42	35
	3-1 Female	176	-	-	123	-	-
	3-2 Female	168	141	163		-27	22
	3-3 Female	184	143	163		-41	20

- = Animal dead

Table 6             Individual Necropsy Findings - 2000 mg/kg

Dose Level mg/kg	Animal Number and Sex	Time of Death	Macroscopic Observations
2000	2-0 Female	Killed Day 14	No abnormalities detected
	3-0 Female	Killed Day 14	No abnormalities detected
	3-1 Female	Found dead 7	Liver: dark Kidneys: pale Stomach: unable to examine, animal cannibalised
	3-2 Female	Killed Day 14	No abnormalities detected
	3-3 Female	Killed Day 14	Liver: pale

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

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

Executive summary:

The study was performed to assess the acute oral toxicity of the test material in the Wistar strain rat. The method was designed to meet the requirements of the following:

- OECD Guidelines for Testing of Chemicals No 420 “Acute Oral Toxicity - Fixed Dose Method” (2001)

-  Method B1 bis Acute Toxicity (Oral) of Commission Regulation (EC) No. 440/2008

Following a sighting test at dose levels of 300 mg/kg and 2000 mg/kg, a further group of four fasted females was given a single oral dose of test material at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

One animal treated at a dose level of 2000 mg/kg was found dead seven days after dosing.

Signs of systemic toxicity noted in animals treated at a dose level of 2000 mg/kg were hunched posture, diarrhoea, diuresis, pilo-erection, emaciation and dehydration. Surviving animals treated at a dose level of 2000 mg/kg appeared normal ten to thirteen days after dosing. There were no signs of systemic toxicity noted in the animal treated at a dose level of 300 mg/kg.

Surviving animals treated at a dose level of 2000 mg/kg showed either no gain in bodyweight or bodyweight loss during the first week but expected gains in bodyweight during the second week. The animal treated at a dose level of 300 mg/kg showed expected gains in bodyweight during the study.

Dark liver and pale kidneys were noted at necropsy of the animal treated at a dose level of 2000 mg/kg that died during the study but the stomach could not be examined as the animal was cannibalised. Pale liver was noted at necropsy of one animal treated at a dose level of 2000 mg/kg that was killed at the end of the study. No abnormalities were noted at necropsy of all other animals that were killed at the end of the study.

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

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 22 September 2010 and 29 September 2010.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted to GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

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

Species:

rat

Strain:

Wistar

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 of age
- Weight at study initiation: at the start of the study the animals weighed at least 200g
- Housing: The animals were individually housed in suspended solid floor polypropylene cages furnished with woodflakes.
- Diet/water: Free access to mains drinking water and food (2014 Teklad Global Rodent diet supplied by Harlan Laboratories U.K. Ltd., Oxon, UK) was allowed throughout 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.
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25°C
- Humidity (%): 30 to 70%
- Air changes (per hr): 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

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- % coverage: approximately 10% of the total body surface area
- 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): after the 24-Hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with arachis oil BP to remove any residual test material.
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 1.77 ml/kg (2000 mg/kg)
- Concentration (if solution): used as supplied
- Constant volume or concentration used: yes

Duration of exposure:

24 hours

Doses:

2000 mg/kg

No. of animals per sex per dose:

1 male and 1 female

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 7 days
- Frequency of observations and weighing: The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for seven days. Individual bodyweights were recorded prior to application of the test item on Day 0 and at death (Day 7).
- Necropsy of survivors performed: yes
- Other examinations performed: 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.

Statistics:

Data evaluations included the relationship, if any, between the exposure of the animal to the test item 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 item was made.
The results were evaluated according to EU labelling regulations Commission Directive 2001/59/EC for classification and labelling of dangerous substances.

Remarks on result:

other: Inconclusive

Mortality:

Both animals were 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 were hunched posture, pilo-erection, lethargy, dehydration and pallor of the extremities.

Gross pathology:

Raised limiting ridge of the stomach and scattered dermal haemorrhage at the sub cutaneous site of application were noted at necropsy.

Other findings:

Very slight or well-defined erythema and hardened dark brown black coloured scab were noted at both test sites. Additional signs of dermal irritation noted at the test site of the male were hardened light brown coloured scab and scab cracking. Additional signs of dermal irritation noted in the female were haemorrhage of dermal capillaries, hardened light brown coloured scab, small areas of pale green coloured dermal necrosis scattered around the edges of the test site, blanching of the skin and hardened dark brown coloured scab, approximately 10 mm x 20 mm in size, surrounded by loss of skin elasticity and light brown discolouration of the epidermis. Adverse dermal reactions prevented accurate evaluation of erythema and oedema at both test sites six and seven days after dosing. The reactions noted in the male were considered to be indicative of dermal corrosion.

Due to severe/corrosive dermal reactions no further animals were treated with the test item.

Table 1              Individual Clinical Observations and Mortality Data

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Initiation of Exposure (Hours)				Effects Noted After Initiation of Exposure (Days)
		½	1	2	4	1	2	3	4	5	6	7
2000	1-0 Male	0	0	0	0	0	0	0	0	H	HPDh	HPDhEX*
	2-0 Female	0	0	0	0	0	0	0	0	H	HPLDh	HPLDhEX*

0 = No signs of systemic toxicity

H = Hunched posture

P = Pilo-erection

L = Lethargy

Dh = Dehydration

E = Pallor of the extremities

X* = Animal killed for humane reasons due to the approach of the moderate severity limit set by the UK Home Office

Table 2              Individual Dermal Reactions

Dose Level mg/kg		Animal Number and Sex		Observation		Effects Noted After Initiation of Exposure (Days)
			1			2		3		4		5		6		7
2000		1-0 Male		Erythema		0		1		1		1		1		?e		?e
			Oedema		0		0		0		0		0		?od		?od
			Other		0		0		0		0		0		St		SpSk
		2-0 Female		Erythema		1		1		0		0		0		?e		?e
			Oedema		0		0		0		0		0		?od		?od
			Other		0		0		0		Hd		Hd		St		NBlSt*LeBr

0 = No reactions

Hd = Haemorrhage of dermal capillaries

St = Hardened dark brown black coloured scab

Sp = Hardened light brown coloured scab

Sk = Scab cracking

N = Small areas of pale green coloured dermal necrosis scattered around the edges of the test site

Bl = Blanching of the skin

St* = Hardened dark brown coloured scab, approximately 10 mm x 20 mm in size

Le = Loss of skin elasticity

Br = Light brown discolouration of the epidermis

?e = Adverse dermal reactions prevent accurate evaluation of erythema

?od = Adverse dermal reactions prevent accurate evaluation of oedema

Table 3              Individual Bodyweights and Weekly Bodyweight Changes

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			At Death	Bodyweight Change (g) During Week
		0	7	14		1	2
2000	1-0 Male	223	-	-	166	-	-
	2-0 Female	211	-	-	160	-	-

- = Animal dead

Table 4              Individual Necropsy Findings

Dose Level mg/kg	Animal Number and Sex	Time of Death	Macroscopic Observations
2000	1-0 Male	Humanely killed Day 7	Stomach: raised limiting ridge Sub-cutaneous at the site of application: scattered dermal haemorrhage
	2-0 Female	Humanely killed Day 7	Stomach: raised limiting ridge Sub-cutaneous at the site of application: scattered dermal haemorrhage

 

Interpretation of results:

other: inconclusive

Remarks:

Criteria used for interpretation of results: not specified

Conclusions:

The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat could not be determined, as due to severe/corrosive dermal reactions, the animals were killed for humane reasons at 7 days.

Executive summary:

The study was performed to assess the acute dermal toxicity of the test item in the Wistar strain rat. The method was designed to meet the requirements of the following:

 OECD Guidelines for the Testing of Chemicals No. 402 “Acute Dermal Toxicity” (adopted 24 February 1987)

 Method B3 Acute Toxicity (Dermal) of Commission Regulation (EC) No. 440/2008

Initially, two animals (one male and one female) were given a single, 24-hour, semi-occluded dermal application of the undiluted test item to intact skin at a dose level of 2000 mg/kg bodyweight. Based on the results of the initial test, no further animals were treated. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Both animals were killed for humane reasons seven days after dosing, due to the approach of the moderate severity limit set by the UK Home Office.

Signs of systemic toxicity noted were hunched posture, pilo-erection, lethargy, dehydration and pallor of the extremities.

Signs of dermal irritation noted were well-defined erythema, haemorrhage of dermal capillaries, hardened light brown, dark brown or dark brown black coloured scab, scab cracking, blanching of the skin, loss of skin elasticity, light brown discolouration of the epidermis and small areas of pale green coloured dermal necrosis. The reactions noted in the male were considered to be indicative of dermal corrosion. Bodyweight loss was noted over the study period.

Raised limiting ridge of the stomach and scattered dermal haemorrhage at the sub cutaneous site of application were noted at necropsy.

The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat could not be determined, as due to severe/corrosive dermal reactions, the animals were killed for humane reasons at 7 days.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Additional information

ORAL

Key value for chemical safety assessment:

LD50 (oral): >2000 mg/kg bw

The key study (Sanders, 2010) was performed to assess the acute oral toxicity of the test material in the Wistar strain rat. The method was designed to meet the requirements of the following:

OECD Guidelines for Testing of Chemicals No 420 “Acute Oral Toxicity - Fixed Dose Method” (2001)

Method B1 bis Acute Toxicity (Oral) of Commission Regulation (EC) No. 440/2008

A reliability score of 1 was assigned according to Klimisch, 1997 as the study was conducted to recognised guidelines and GLP.

Following a sighting test at dose levels of 300 mg/kg and 2000 mg/kg, a further group of four fasted females was given a single oral dose of the undiluted test material at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

 

DERMAL

Key value for chemical safety assessment:

LD50 (dermal): Could not be determined due to severe/corrosive dermal reactions. The animals were killed for humane reasons at 7 days.

The key study (Sanders, 2010) was performed to assess the acute dermal toxicity of the test material in the Wistar strain rat. The method was designed to meet the requirements of the following:

 OECD Guidelines for the Testing of Chemicals No. 402 “Acute Dermal Toxicity” (adopted 24 February 1987)

 Method B3 Acute Toxicity (Dermal) of CommissionRegulation (EC) No. 440/2008

A reliability score of 1 was assign according to Klimisch, 1997 as the study was conducted to recognised guidelines and GLP.

Initially, two animals (one male and one female) were given a single, 24 -hour, semi-occluded dermal application of the undiluted test item to intact skin at a dose level of 2000 mg/kg bodyweight. Based on the results of the initial test, no further animals were treated. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Justification for classification or non-classification

Oral:

The key parameter chosen for acute toxicity for the oral route was greater than the criteria set out in Directive 67/548/EEC and also Regulation (EC) no 1272/2008, therefore classification for acute toxicity was not considered to be necessary.

Dermal:

The classification for the test substance could not be determined as due to severe/corrosive dermal reactions seen, the animals were killed for humane reasons at 7 days. In accordance with EC Regulation 1907/2006, Annex VIII, Column 2, point 8.5, this study generally does not need to be conducted if the substance is classified as corrosive, and therefore this endpoint is not necessary for registration purposes. It should be noted that this study was undertaken on the basis that the in vitro skin corrosion study (Warren, 2010) gave the result of "non-corrosive". The study does not technically fit the criteria for "corrosive" with regards to Directive 67/548/EEC and also Regulation (EC) no 1272/2008, however corrosive effects are seen in this study around day 5. Expert judgement has been applied to classify this substance as corrosive.