Dihydro-2,2-dioctyl-6H-1,3,2-oxathiastannin-6-one

Endpoint summary

Description of key information

By read-across to Dioctyltin oxide, target organ of Dioctyltin mercaptopropionate is considered to be the thymus. Due to studies on Dioctyltin dichloride, the thymus toxicity of dioctyltins is judged an acute effect.

Read-across to structurally similar substance: DOTO (Dioctyltin oxide)

Under the conditions of this study, based on the effects noted in the thymus in both male and female rats in the 25 mg/kg diet groups, the NOAEL was concluded to be the lowest group tested, 5 mg/kg diet which was equivalent to 0.3-0.4 mg/kg bw/day for male animals and 0.3-0.5 mg/kg bw/day for female animals.

After correction for molecular weight, the NOAEL values from read-across to Dioctyltin oxide were, 0.4 -0.5 mg/kg bw/day for male animals and 0.4-0.6 mg/kg bw/day for female animals.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

0.4 mg/kg bw/day

Study duration:

subacute

Species:

rat

System:

immune system

Organ:

thymus

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Read-across to structurally similar substance: DOTO (Dioctyltin oxide)

The repeated dose toxicity of DOTO was assessed in a repeated dose toxicity and reproductive and developmental screening study in rats. The study was performed in accordance with GLP and to the standardised guideline OECD 422. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Only one death was noted during the study, and this was not attributed to toxicity of DOTO. Based on the effects noted in the thymus in both male and female rats in the 25 mg/kg diet groups, the NOAEL was concluded to be the lowest group tested, 5 mg/kg diet which was equivalent to 0.3-0.4 mg/kg bw/day for male animals and 0.3-0.5 mg/kg bw/day for female animals.

After correction for molecular weight, the NOAEL values from read-across to Dioctyltin oxide were, 0.4 -0.5 mg/kg bw/day for male animals and 0.4-0.6 mg/kg bw/day for female animals.

Justification for classification or non-classification

Dioctyltin oxide (DOTO) induced thymus effects in a OECD 422 guideline study.

Several studies on the structure surrogate Dioctyltin dichloride show, that Dioctyltin dichloride causes an adverse effect in the immune system after a single exposure. Under consideration of the different bioavailability (DOTC >> DOTO) and from human data (EMA, FDA) it is considered appropriate to classify Dioctyltin oxide in accordance with the Regulation (EC) No. 1272/2008 and Directive 67/548/EEC, based on the observations in the thymus, as STOT Single. Exp. 2: H371. Similar effects as for DOTO are expected for Dioctyltin mercaptopropionate based on structural similarity. Target substance and source substances share the identical organotin moiety, and the organotin moiety is generally recognized as the relevant toxophore of organotins. Mercaptopropionic acid, which is as mercaptopropionate the moiety of the target substance which is not covered by the source substance, is not classified for repeated dose toxicity.

In accordance with the Regulation (EC) No. 1272/2008, based on the observations in the thymus, Dioctyltin mercaptopropionate is classified as STOT Single. Exp. 2: H371.