Bis(dodecylthio)dioctylstannane

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 September 2016 to 20 September 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study / Non GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD 111

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EU Method C.7

Deviations:

no

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Bis(dodecylthio)dioctylstannane

EC Number:

244-841-3

EC Name:

Bis(dodecylthio)dioctylstannane

Cas Number:

22205-30-7

Molecular formula:

C40H84S2Sn

IUPAC Name:

bis(dodecylsulfanyl)dioctylstannane

Test material form:

liquid

Details on test material:

- Appearance: pale yellow liquid
- Storage: In original container, at 15 to 25 °C

Radiolabelling:

not specified

Results and discussion

Any other information on results incl. tables

HYDROLYSIS AT PH 4,7 AND 9

- Samples of the test material were added to the respective buffer solutions at 50 °C for 5 days (120 h). At No pH value the 119Sn-NMR spectra of the extracted reaction products show signs of hydrolysis.

- The half-life time of the test material under the conditions of the study is > 1 year. The test material is considered as hydrolytically stable

HYDROLYSIS AT PH 1.2

- 1 g (1.3 mMol) of the test material was added to an excess 0.1 M Hydrochloric Acid at 37°C for 4 hours and extracted with hexane after cooling down to room temperature. The 119Sn-NMR spectrum of the organic extract shows a decrease of the products peak and an increase of the breakdown product, the monochloride of the substance DOT(-SLau)Cl.

- A small side sharp side peak in the broad signal for the monochloride appears at 144 ppm and cannot be reliably quantified or assigned to a organotin substance. The chemical shift points to a disulfur bridged organotin compound. No signal for DOTC could be identified in the 119Sn spectrum.

- The composition of the test material hydrolysate at pH 1.2 based on 119Sn-NMR analysis was:

DOT(-SLau)2 30 Mol% and DOT(-SLau)Cl 70 Mol%.

- In order to assure no DOTC has been formed, the NMR sample was spiked with DOTC. The spectra showed a further reaction between the residual dioctyltin-di-thiolaurate and the dioctyltin dichloride resulting in additional dioctyltin-monochloro mono thiolaurate according to the following equation:

Oc2Sn(S-Lau)2 + Oc2SnCl2 = 2 Oc2Sn(SLau)Cl

MASS BALANCE RECIVERY RATES

pH 4: 100 %

pH 7: 98 %

pH 9: 100 %

pH 1.2: 103 %

ATOMIC ABSORPTION SPECTOMETRY

- The aqueous phases of the low pH hydrolysis has been analysed after extraction with hexane by AAS and contained less than 5 mg/L Sn.

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study, the test material was is hydrolytically stable at pH 4, 7 and 9. At pH 1.2 the only identifiable breakdown product was the monochloride of the test material chloro, dodecylthio dioctylstannane (DOT-SLau Cl). It appears besides the unreacted test material. DOTC was not detected in the organic extract. The high recovery of substances in the hexane extract and the low tin content of the aqueous phase (< 5 mg/L) indicate that no reaction products remained in the aqueous phase of the experiment.

Executive summary:

The hydrolysis of the test material as a function of pH was investigated in accordance with the standardised guidelines OECD 111 and EU Method C.7.

The stability of the test material was investigated at pH 4, 7 and 9 and pH 1.2 using NMR spectroscopy.

The study showed that the test material was hydrolytically stable at pH 9, 7 and 4. After 5 days of hydrolysis at 50°C less than 10 % of the test material was hydrolysed (t 0.5 at 25°C > 1 year).

At simulated gastric conditions (0.1 M HCl /pH 1.2 /37°C/ 4 h) the only identifiable breakdown product was the monochloride of the test material chloro, dodecylthio dioctylstannane (DOT-SLau Cl). It appears besides the unreacted test material. DOTC was not detected in the organic extract.

A spiking experiment confirmed non-presence of DOTC in the reaction mixture and showed that DOTC reacts with the test material forming it’s monochloride.

The high recovery of substances in the hexane extract and the low tin content of the aqueous phase (< 5 mg/L) indicate that no reaction products remained in the aqueous phase of the experiment.