Bis(dodecylthio)dimethylstannane

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 October 2017 to 03 November 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Objective of study:

other: hydrolysis as a function of pH

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

no

Radiolabelling:

not specified

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 (1.8 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. A new peak at 158 ppm , a chemical shift area which is typical for disulphur bridged organotin compounds. However, the peak cannot be unequivocally assigned to a substance.

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

DMT(-SLau)2 22 Mol%, DMT(-SLau)Cl 70 Mol% and 8 Mol% unknown.

MASS BALANCE RECIVERY RATES

pH 4: 83 %

pH 7: 98 %

pH 9: 99 %

pH 1.2: 79 %

ATOMIC ABSORPTION SPECTOMETRY

- The aqueous phases of the low pH hydrolysis has been analysed after extraction with hexane by AAS and contain 1720 mg/L Sn.

Conclusions:

Under the conditions of this study, the test material was hydrolytically stable at pH 4, 7 and 9. At pH 1.2 the only identifiable breakdown product was the monochloride of the test material, chlorododecylthio dimethylstannane (DMT-SLau Cl). It appeared besides the unreacted test material with traces of a not further characterised substance. DMTC was not detected in the organic extract. The lower recovery of substance in the hexane extract and the content of 1720 mg/L tin remaining in the aqueous phase indicates that the dimethyltin cation remains in a soluble form in water.

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 shows that the test material is 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 (half life 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, chlorododecylthio dimethylstannane (DMT-SLau Cl). It appears besides the unreacted test material with traces of a not further characterised substance. DMTC was not detected in the organic extract.

The lower recovery of substance in the hexane extract and the content of 1720 mg/L tin remaining in the aqueous phase indicates that the dimethyltin cation remains in a soluble form in water.

Description of key information

Hydrolysis as a function of pH

Under the conditions of this study, the test material was hydrolytically stable at pH 4, 7 and 9. At pH 1.2 the only identifiable breakdown product was the monochloride of the test material, chlorododecylthio dimethylstannane (DMT-SLau Cl). It appears besides the unreacted test material with traces of a not further characterised substance. DMTC was not detected in the organic extract. The lower recovery of substance in the hexane extract and the content of 1720 mg/L tin remaining in the aqueous phase indicates that the dimethyltin cation remains in a soluble form in water.

Additional information

Hydrolysis as a function of pH

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 shows that the test material is 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 (half life 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 chlorododecylthio dimethylstannane (DMT-SLau Cl). It appears besides the unreacted test material with traces of a not further characterised substance. DMTC was not detected in the organic extract.

The lower recovery of substance in the hexane extract and the content of 1720 mg/L tin remaining in the aqueous phase indicates that the dimethyltin cation remains in a soluble form in water.