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Administrative data

Key value for chemical safety assessment

Additional information

In vitro Gene Mutation study in Bacteria

The key studies for this endpoint were chosen on the basis that they were conducted to the appropriate OECD guidelines. Both were well reported, used the required number of test strains, but did lose reliability by only having a purity of 72 % dimethyltin dichloride (remainder is monomethyltin trichloride). Both studies gave a negative result for genetic toxicity.

In conclusion, dimethyltin dichloride is considered not to induce genetic toxicity in bacterial cells.

In vitro Cytogenicity study in Mammalian Cells or In vitro Mouse Micronucleus test

The key study for this endpoint was conducted in accordance with an OECD guideline, was well reported, but lost reliability for only containing 74.2% dimethyltin dichloride, with the remainder being 25.8% monomethyltin trichloride. The test gave a positive result for genetic toxicity.

In vitro Gene Mutation, plus DNA damage and further in vivo studies

The key study for mammalian cell gene mutation was selected on the basis that is was a well reported study conducted to an OECD guideline. The test demonstrated that dimethyltin dichloride is not genetically toxic to mammalian cells.

The key study for DNA damage/repair was conducted in accordance with an OECD guideline, was well reported, but lost reliability for only containing 78.8% dimethyltin dichloride with the remainder being 21.5% monomethyltin trichloride. The test was in the form of an in vivo UDS assay. The test gave a negative result for genetic toxicity.

The results of all the other supporting studies were negative.


Justification for selection of genetic toxicity endpoint
No single study has been selected due to the range of different types of genetic toxicity examined.

Short description of key information:
There were 4 reliable in vitro studies showing a negative results except for the in vitro chromosome aberration assay which was positive. The In vivo UDS study was negative.

Ames (Salmonella) Key Study: Holmes (1990): Negative
Ames (E-Coli) Key Study: Holmes (1990): Negative
Chromosome Aberration (in vitro) Key Study: Blachman (1990): positive with metabolic activation, negative without metabolic activation
Mammalian Cell Gene Mutation Assay Key Study: Bakke (1990): Negative
Unscheduled DNA Synthesis (in vivo) Key Study: Hamilton (1990): Negative

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Dimethyltin dichloride gave overall negative results for genetic toxicity to the germ cell, mammalian cell and to DNA damage/repair. A positive result was seen in the in vitro chromosome aberration test while all in vivo tests were negative. In conclusion, there is insufficient evidence to classify dimethyltin dichloride for genetic toxicity.

In accordance with the criteria outlined in Regulation (EC) No. 1272/2008 (CLP) and Directive 67/548/EEC (DSD), the substance does not meet the criteria for classification for genotoxicity.