Dibutyldimethoxystannane

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route

Dose descriptor:

NOAEL

0.3 mg/kg bw/day

Additional information

All dibutyltin compounds degrade into dibutyltin and the appropriate ligand, and so on this basis, it is possible to read-across between the different dibutyltin compounds to address the toxicity to reproduction endpoints. As no toxicity to reproduction data are available for the substance in question this endpoint has been addressed by the submission of studies performed on dibutyltin dichloride and using read-across from these studies.In a single-generation reproduction screening study, any influence of dibutyltin chloride on reproduction occurred only at maternally toxic levels; a maternal NOAEL of ca. 0.3 mg/kg bw/day was estimated.

Short description of key information:
The following study has been submitted to address the toxicity to reproduction endpoint:

Waalkens-Berendsen DH (2003). Dibutyldichlorostannane (CAS # 683-18-1): Reproduction/developmental toxicity screening test in rats. Testing laboratory: TNO, Project Organisation, Ecotoxicology, Utrechtseweg 48, P. O. Box 370, 3700 AJ Zeist, The Netherlands. Report no.: V 4906. Owner company: Organotin Environmental Programme (ORTEP) Association, Stabilizer Task Force. Report date: 2003-12-04.

This study has been allocated a Klimisch score of 2 on the basis that it was performed to the appropriate guideline under GLP and the test material was read-across to the substance in question.

Effects on developmental toxicity

Description of key information

The following studies have been submitted to address the developmental toxicity/teratogenicity endpoint:
Ema M & Harazono A (2000). Adverse effects of dibutyltin dichloride on initiation and maintenance of rat pregnancy. Reproductive Toxicology, 14, (2000), 451-456.
Ema et al (1991). Teratogenicity of di-n-butyltin dichloride in rats. Toxicology Letters, 58 (1991) 347-356.
Ema et al (1992). Susceptible period for the teratogenicity of di-n-butyltin dichloride in rats. Toxicology, 73 (1992) 81-92.
Ema et al (1995). Comparative Developmental Toxicity of Butyltin Trichloride, Dibutyltin Dichloride and Tributyltin Chloride in Rats. JOURNAL OF APPLIED TOXICOLOGY, VOL. 15(4), 297-302 (1995).
Ema et al (1996). Comparative Developmental Toxicity of Di-, Tri- and Tetrabutyltin Compounds after Administration during Late Organogenesis in Rats. JOURNAL OF APPLIED TOXICOLOGY, VOL. 16(1), 71-76 (1996).
Noda T et al (1993). Teratogenic effects of various di-n-butyltins with different anions and butyl(3-hydroxybutyl) tin dilaurate in rats. Toxicology, 85, 149-160.
Osterburg I (1993). Dibutyltin dichloride oral (gavage) teratogenicity study in the rat. Report no.: 380-211. Report date: 1994-11-11.
Osterburg (1993) has been allocated a Klimisch score of 2 as the study was conducted to recognised guidelines and GLP using dibutyltin dichloride as the test material. Noda et al (1993), was allocated a Klimisch score of 2 on the basis that the number of animals and dose groups  were less than the recommended amounts in OECD Guideline 414 and there were partial organogenetic period exposures. The study meets generally accepted scientific standards, is well documented, and acceptable for assessment.
The test material, dibutyltin dichloride of the Osterburg (1993) study, was read-across to the substance in question.
All other references have been allocated a Klimisch score of 4.

Effect on developmental toxicity: via oral route

Dose descriptor:

NOAEL

1 mg/kg bw/day

Additional information

All dibutyltin compounds degrade into dibutyltin and the appropriate ligand (in gastric conditions, dibutyltin dichloride), on this basis, it is possible to read-across between the different dibutyltin compounds to address in vivo toxicity endpoints. As no adequate developmental toxicity studies are available on the material itself, this endpoint has been addressed by the submission of studies performed on dibutyltin dichloride and using a read-across approach. In several studies of development and teratogenicity, various dibutyltin substances were repeatably and reliably associated with a syndrome of malformations of the oroglossal region. Malformations appear to be limited to dose levels also associated with maternal toxicity; however, it is not clear how relevant maternal toxicity may be to the syndrome of malformations reported.

Justification for classification or non-classification

The substance is classified with Repro. Cat. 2; R60 -61 according to Directive 67/548/EEC. According to Regulation (EC) no 1272/2008 the test substance would be classified as a Repr. 1B with Hazard statement: H360FD: May damage fertility or the unborn child and should be accompanied with the signal word 'Danger'.