Dibutylbis(dodecylthio)stannane

Endpoint summary

Description of key information

Corrosivity:
The test article was qualified, categorized, and found to be compatible with the Corrositex® test system. 
The results obtained from the evaluation of four replicate tests demonstrated that a mean time of >120.0 minutes was required to destroy the synthetic biobarriers. These findings lead to the classification of this test article as a Non-Corrosive material.
Skin irritation:
In a study conducted at Industrial Bio-Test Laboratories, 1977, New Zealand White rabbits had 0.5 ml of test material applied undiluted to intact and abraded areas of thier skin. 3 rabbits were used per dose. The test material was applied for 24 hours under occluded conditions.
Irritating effects were seen in all animals. After 72 hours second degree chemical burns that will not result in fibrosis were noted. Sites with second degree chemical burns were given maximum irritation scores of 4 for both erythema and edema to obtain a primary irritation score.
Eye irritation:
Two studies of equal reliability are available and have been used in a weight of evidence approach to address this endpoint due to restrictions seen in both studies.
In a study conducted at Industrial Bio-Test Laboratories, 1977, 3 New Zealand White rabbits had 0.1 ml of test material applied undiluted to their right eyes. The left eye of each animal served as a control.
The study was conducted according to methods that were comparable to OECD 405.
Redness of the conjunctiva was noted in all animals and had fully reversed by 14 days.
In a study conducted at MB Research Laboratories, 2010 one healthy New Zealand White rabbit (male), free from evidence of ocular irritation and corneal abnormalities, was dosed with 0.1 ml of the test material. The study was conducted according to OECD 405.
There was no corneal opacity or iritis noted at any observation period. Conjunctival irritation cleared in the one eye by day 14.
The test material is not an ocular irritant.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Corrosivity

- The key study (Tao, 2010) was performed to determine chemical corrosivity and assign U.N. Packing Group classification

for chemicals or mixtures. The Corrositex^® method was used, this is designed to comply with the standards set forth in OECD Guidelines for the Testing of Chemicals, Guideline 435 adopted July 19, 2006.

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

Skin irritation

- The key study (Scibor & Mastri, 1977) was performed to evaluate the potential of the test material to cause irritation to the skin. The test procedure was modeled after that of Draize and was considered to have been conducted to methods similar to that of OECD 404 but with deviations.

A reliability score of 2 was assigned according to Klimisch, 1997 as the methodology was similar to OECD guidelines, however the study pre-dates recent guidelines and the following deviations were noted:

- Test material left on for 24 hours.

- Sites were occluded.

- No 48 hours reading were taken.

- No information on observations for up to 14 days and so reversibility could not be determined.

Eye irritation

Due to restrictions seen in both eye irritation studies, the two studies have been used as a weight of evidence approach to address this endpoint. Both studies are of equal reliability.

- The Scibor & Mastri, 1977 study was performed to evaluate the potential of the test material to cause irritation to the eye. The test procedure was modeled after that of Draize and was considered to have been conducted to methods similar to that of OECD 405.

A reliability score of 2 was assigned according to Klimisch, 1997 as the methodology was similar to OECD guidelines, however the study pre-dates GLP and no details were given regarding animal maintenance.

- The Hall, 2010 study was conducted to determine the irritant or corrosive effects, if any, of a test article when instilled into the rabbit eye. This study was designed to comply with the standards set forth in OECD Guidelines For Testing Chemicals, Number 405, adopted April 24, 2002.

A reliability score of 2 was assigned according to Klimisch, 1997 as initially only one animal was used and at the request of the Sponsor, no additional animals were dosed.

Effects on skin irritation/corrosion: irritating

Justification for classification or non-classification

Skin irritation

Although it is not technically possible to classify according to Directive 67/548/EEC or Regulation (EC) no. 1272/2008 due to the fact that no 48 hour readings were reported in the key study, it can be seen from the relatively high erythema scores seen in all 3 animals at 24 (mean score: 2.7) and 72 hours (mean score: 4), that even disregarding the 48 hour scores the test material will be considered to be irritating to the skin.  

It is stated in the study report that second degree chemical burns were seen at the 72 hour observation period. These types of effects are normally considered indicative of corrosive effects. However as the exposure period was 24 hours under occlusive conditions and that the solvent used to remove the test material may not have been wholly appropriate for this purpose, whilst it is indeed possible to determine that the substance is irritant to skin, it is not considered possible to conclusively determine that these corrosive effect would have been seen following a 4 hour treatment. As such it is considered inappropriate to classify this substance as corrosive.

With this in mind the test substance is considered to be classified an an irritant to the skin and will therefore be classified as R38, irritating to skin according to Directive 67/548/EEC and as a Category 2 irritant, hazard statement H315: causes skin irritation and the 'warning' symbol according to Regulation (EC) no 1272/2008.

Eye irritation

Based on the available data for this endpoint, the test substance was considered to be non irritanting to the eyes according to the criteria set out in Directive 67/548/EEC and Regulation (EC) no 1272/2008.