2,2-dioctyl-1,3,2-oxathiastannolan-5-one

Endpoint summary

Description of key information

ORAL
Discriminating dose = 300 mg/kg bw, female rat, OECD 420, EU Method B.1 bis, Sanders (2013a).
DERMAL
LD50 > 2000 mg/kg bw (dioctyltin oxide), male/female rat, OECD 402, EU Method B.3, Sanders (2012a).

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:

4 December 2012 to 27 December 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

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
- Age at study initiation: 8 - 12 weeks.
- Weight at study initiation: 160 - 175 g. The bodyweight variation did not exceed ± 20 % of the initial bodyweights.
- Fasting period before study: yes (animals were fasted overnight immediately before dosing and for approximately three to four hours after dosing).
- Housing: animals were housed in groups up to four in suspended solid-floor polypropylene cages furnished with wood flakes.
- Diet: provided ad libitum.
- Water: mains drinking water, ad libitum.
- Acclimation period: at least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): at least 15 air changes per hour.
- Photoperiod (hrs dark / hrs light): 12 hours light / 12 hours dark.

Route of administration:

oral: gavage

Vehicle:

DMSO

Details on oral exposure:

PREPARATION OF DOSING FORMULATIONS
The test material was freeze dried using liquid nitrogen, ground to a powder and then freshly prepared, as required, as a solution in dimethyl sulphoxide DMSO. To aid preparation, the formulation was warmed in a water bath at 85 °C for 1 hour. The formulation was allowed to cool before dosing. DMSO was used because the test material did not dissolve/suitably suspend in distilled water/arachis oil BP.

The test material was formulated within 2 hours of being applied to the test system.

VEHICLE
- Concentration in vehicle: 200 mg/mL (2000 mg/kg dose); 30 mg/mL (300 mg/kg dose).

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg
The volume administered to each animal was calculated according to the fasted bodyweight at the time of dosing.

Doses:

2000 mg/kg bw (sighting test)
300 mg/kg bw (main test)

No. of animals per sex per dose:

1 (sighting test)
5 (main test)

Control animals:

no

Details on study design:

- Study schedule: a single animal was dosed at 2000 mg/kg. Due to mortality at this dose level, an additional group of animals was treated at 300 mg/kg. Treatment of the animals was sequential; sufficient time was allowed between each dose level to confirm survival of the previously dosed animals.
- Duration of observation period following administration: 14 days
- Frequency of observations: clinical observations were made ½, 1, 2 and 4 hours after dosing and then daily thereafter. Morbidity and mortality checks were made twice daily.
- Frequency of weighing: individual bodyweights were recorded on Day 0 (the day of dosing) and on Days 7 and 14 or at death.
- Necropsy of survivors performed: yes (this consisted of an external examination and opening of the abdominal and thoracic cavities). The appearance of any macroscopic abnormalities was recorded.

Statistics:

An estimate of the LD50 value was made according to the observed mortality rate.

Sex:

female

Dose descriptor:

LD50

Effect level:

300 - 2 000 mg/kg bw

Based on:

test mat.

Sex:

female

Dose descriptor:

discriminating dose

Effect level:

300 mg/kg bw

Based on:

test mat.

Mortality:

The animal dosed at 2000 mg/kg was killed for humane reasons, eight days after dosing, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project Licence.
None of the animals dosed at 300 mg/kg died during the study.

Clinical signs:

other: Signs of systemic toxicity noted on the animal dosed at 2000 mg/kg included hunched posture, pilo-erection, tiptoe gait, emaciation, dehydration, and palor of the extremities and hypothermia. In the group dosed at 300 mg/kg clinical signs included hunched

Gross pathology:

Pale liver and kidneys were noted at necropsy in the animal dosed at 2000 mg/kg.
No abnormalities were noted at necropsy of animals dosed at 300 mg/kg.

Interpretation of results:

Toxicity Category IV

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the study the acute oral LD50 of the test material in the female Wistar strain rat was estimated to be in the range of 300 to 2000 mg/kg bw.

Executive summary:

The acute oral toxicity of the test material was investigated in a GLP study which was conducted in accordance with the standardised guidelines OECD 420 and EU Method B.1 bis, following the fixed dose method.

Following a sighting test in a single animal dosed 2000 mg/kg bw, a group of five fasted females was given a single oral dose of test material, as a solution in dimethyl sulphoxide, at a dose level of 300 mg/kg bw. Clinical signs and bodyweight development were monitored during the study and all animals were subjected to gross necropsy at study termination on day 14.

The animal treated at 2000 mg/kg was killed for human reasons, eight days after dosing, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project Licence. There were no deaths in the group dosed at 300 mg/kg.

Signs of systemic toxicity noted in the animals treated at 2000 mg/kg were hunched posture, pilo-erection, tiptoe gait, emaciation, dehydration, pallor of the extremities and hypothermia. Ataxia and/or hunched posture were noted in animals treated at 300 mg/kg.

Pale liver and kidneys were noted at necropsy of the animal treated at 2000 mg/kg. No abnormalities were noted a necropsy of animals treated at a dose level of 300 mg/kg.

Under the conditions of the study the acute oral LD50 of the test material in the female Wistar strain rat was estimated to be in the range of 300 to 2000 mg/kg bw, and the discriminating dose was considered to be 300 mg/kg bw.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

discriminating dose

Value:

300 mg/kg bw

Quality of whole database:

One GLP and guideline study is available on the registered substance. Supporting information is available in the form of a study which was broadly conducted in accordance with standardised guideline 401 together with four acute toxicity values as reported in literature. Furthermore, there is a study available on the read across substance, dioctyltin oxide. Overall the quality of the database is good.

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:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

13 June 2012 - 27 June 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study was performed in compliance with GLP and in accordance with the standardised guidelines OECD 402 and EU Method B.3. The study was performed to a high standard sufficient to assess the quality of the presented results. Since the study was conducted on the read across substance, dioctyltin oxide, it has been assigned a reliability score of 2.

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
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: at lest 200 g (weight variation did not exceed ± 20 % of the mean weight for each sex).
- Housing: individually during 24 hour exposure period and in groups of five, by sex, for the remainder of the study in suspended solid-floor polypropylene cages.
- Diet: provided ad libitum
- Water: mains drinking water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25 ºC
- Humidity (%): 30 - 70 %
- Air changes (per hr): at least 15 changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light

Type of coverage:

semiocclusive

Vehicle:

arachis oil

Details on dermal exposure:

TEST SITE
- Area of exposure: on the day before treatment the back and flanks of each animals were clipped free of hair
- % 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
- 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

TEST MATERIAL
- the appropriate amount of test material was moistened with arachis oil BP and applied as evenly as possible to the area of shorn skin

Duration of exposure:

24 hours

Doses:

2000 mg/kg

No. of animals per sex per dose:

5 males and 5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Animals were observed to deaths and overt signs of toxicity 0.5, 1, 2 and 4 hours after dosing and once daily thereafter. The test site was observed daily for evidence of primary irritation and scored according to Draize (1977) (see table 1 in "Any other information on material and methods incl. tables). Individual bodyweights were recorded prior to application of the test material on day 0 and on days 7 and 14.
- 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.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

There were no deaths.

Clinical signs:

other: There were no signs of systemic toxicity.

Gross pathology:

No abnormalities were noted at necropsy.

Other findings:

There were no signs of dermal irritation.

Table 2: Individual Bodyweights and Weekly Bodyweight Changes

Animal no. and sex	Bodyweight (g) at day			Bodyweight change (g) during week
	0	7	14	1	2
1M	309	314	328	5	14
2M	287	303	323	16	20
3M	282	305	332	23	27
4M	399	425	435	26	10
5M	367	358	380	-9	22
1F	202	204	214	2	10
2F	221	226	237	5	11
3F	217	220	232	3	12
4F	214	221	228	7	7
5F	201	202	217	1	15

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the study, the LD50 of the test material in the Wistar strain of rat was determined to be greater than 2000 mg/kg bw.

Executive summary:

The acute dermal toxicity of the test material was investigated in a GLP study which was conducted in accordance with standardised guidelines OECD 402 and EU Method B.3. During the study, a group of ten animals (five males and five females) was given a single, 24 -hour, semi-occluded dermal application of the test material to intact skin at a dose level of 2000 mg/kg bw. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy. Under the conditions of the study there were no deaths and no signs of systemic toxicity. Animals showed normal weight gains and there were no signs of dermal irritation. Furthermore, no abnormalities were noted at necropsy. The acute dermal median lethal dose (LD₅₀) of the test material in the Wistar strain of rat was therefore determined to be greater than 2000 mg/kg bw.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

The study was performed in compliance with GLP and in accordance with the standardised guidelines OECD 402 and EU Method B.3. The study was performed to a high standard sufficient to assess the quality of the presented results. Since the study was conducted on the read across substance, dioctyltin oxide, it has been assigned a reliability score of 2 according to the criteria of Klimisch (1997).

Additional information

Oral

In the key study (Sanders, 2013a), the acute oral toxicity of the test material was investigated in a GLP study which was conducted in accordance with the standardised guidelines OECD 420 and EU Method B.1 bis, following the fixed dose method. Accordingly this study was assigned a reliability score of 1 in accordance with Klimisch (1997).

Following a sighting test in a single animal dosed 2000 mg/kg bw, a group of five fasted females was given a single oral dose of test material, as a solution in dimethyl sulphoxide, at a dose level of 300 mg/kg bw. Clinical signs and bodyweight development were monitored during the study and all animals were subjected to gross necropsy at study termination on day 14. The animal treated at 2000 mg/kg was killed for human reasons. There were no deaths in the group dosed at 300 mg/kg. Signs of systemic toxicity noted in the animals treated at 2000 mg/kg were hunched posture, pilo-erection, tiptoe gait, emaciation, dehydration, pallor of the extremities and hypothermia. Ataxia and/or hunched posture were noted in animals treated at 300 mg/kg. Pale liver and kidneys were noted at necropsy of the animal treated at 2000 mg/kg. No abnormalities were noted a necropsy of animals treated at a dose level of 300 mg/kg. Under the conditions of the study the acute oral LD50 of the test material in the female Wistar strain rat was estimated to be in the range of 300 to 2000 mg/kg bw, and the discriminating dose was considered to be 300 mg/kg bw.

Supporting information is available on the registration substance in the form of a study, reported by Sarasin (1980) during which the acute oral toxicity of the test material was investigated following a method similar to the standardised guideline OECD 401.Accordingly this study was assigned a reliability score of 2 in accordance with Klimisch (1997). During the study groups of 5 male and 5 female rats were orally dosed test material in propylene glycol at 1000, 2000, 3000 and 5000 mg/kg bw. Mortality and clinical signs were recorded at 1, 2, 3, 5, and 24 hours following treatment and daily thereafter. Bodyweight was recorded weekly. Animals were submitted to a necropsy whenever they died or at the end of the 14 day observation period.

Under the conditions of the study, the acute oral LD50 of the test material was determined to be 2294 mg/kg bw with 95 % confidence limits of 1788 to 2883 mg/kg bw.

 

Three acute oral LD50 values for the registered substance have been reported in literature. Summer (2003) reports the LD50 to be 2290 and 1980 mg/kg bw, Klimmer (1969) reports the LD50 to be 945 mg/kg and Smith (1978) reports the LD50 to be between 945 and 1140 mg/kg. Since no information is presented on materials and methods, literature data were assigned a reliability score of 4.

 

In addition to the data that was available on the substance itself, data on the read across substance, dioctyltin oxide, was also considered in a study reported by Bathe (1972). The study was conducted to a guideline similar to that of the OECD 401 standardised guideline, now phased-out. The study was performed to sound scientific principles with a sufficient level of detail to assess the reliability of the data, and was assigned a score of 2 in line with Klimisch (1997). The animals were dosed with the test material in polyethylene glycol at 4640 and 6000 mg/kg bw. No mortalities were observed during the study, all clinical signs observed had alleviated by day 6. Under the conditions of the study, the acute oral LD50 of the test material was found to be greater than 6000 mg/kg bw in male and female rats.

 

The available data are considered to be complete and the result determined in the key study, oral discriminating dose of 300 mg/kg, was taken forward for risk assessment. The supporting data are generally in good agreement with the acute toxicity hazard category 4 thresholds (300 < LD50 ≤ 2000 mg/kg bw).

Inhalation

In accordance with Section 2 Annex XI of Regulation (EC) No. 1907/2006, the acute inhalation study (required in Annex VIII section 8.5.2) does not need to be conducted as the testing is not technically possible due to the physical nature of the substance. The substance is a waxy solid and is therefore unlikely to form an inhalable dust. Exposure via the inhalation route is not considered to be the most appropriate route of exposure. The oral and dermal routes are considered to be the most appropriate routes of exposure, for which sufficient acute toxicity data has been provided.

Dermal

In the key study (Sanders, 2012a) the acute dermal toxicity of the read across substance, dioctyltin oxide, was investigated in a GLP study which was conducted in accordance with standardised guidelines OECD 402 and EU Method B.3. During the study, a group of ten animals (five males and five females) was given a single, 24 -hour, semi-occluded dermal application of dioctyltin oxide to intact skin at a dose level of 2000 mg/kg bw. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy. Under the conditions of the study there were no deaths and no signs of systemic toxicity. Animals showed normal weight gains and there were no signs of dermal irritation. Furthermore, no abnormalities were noted at necropsy. The acute dermal median lethal dose (LD50) of the dioctyltin oxide in the Wistar strain of rat was therefore determined to be greater than 2000 mg/kg bw.

The available data are considered to be complete and the result determined, dermal LD50 > 2000 mg/kg, was taken forward for risk assessment.

Justification for selection of acute toxicity – oral endpoint
Sanders (2013a) was selected as the key study since it was conducted under GLP conditions, on the registration substance, and in accordance with standardised guidelines. Furthermore, it provides the lowest discriminating dose level and thus represents the worst case scenario.

Justification for selection of acute toxicity – inhalation endpoint
A data waiver has been provided to address this endpoint.

Justification for selection of acute toxicity – dermal endpoint
Only one study is available.

Justification for classification or non-classification

Oral

In accordance with the criteria for classification as defined in Annex I of Regulation (EC) No. 1272/2008, the test material meets the criteria for classification as Acute Oral Toxicity Category 4: Harmful if swallowed (H302).

In accordance with the criteria for classification as defined in Directive 67/548/EEC, the test material meets the criteria for classification as Harmful if swallowed, Xn (Harmful) R22.

Dermal

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No. 1272/2008, the test material does not require classification for acute dermal toxicity.