Lithium isooctadecanoate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

- Stability under test conditions: Stable
- Treatment of test material prior to testing: None
- Preliminary purification step: None
- Final preparation of a solid: Applied neat

Remarks on result:

not determinable

Details on results:

On completion of the static re-equilibration period at 20°C, the saturated solution was observed to be a hazy suspension. Following centrifugation, the supernatant still presented a strong Tyndall beam, indicating light scattering originating from a dispersion of emulsified, excess, undissolved material remaining suspended in the solution. On filtration of the supernatant through a 0.2 µm filter, the strong Tyndall beam response remained in the resulting filtrate, indicating a colloidal nature to the dispersion.

The behaviour of the test item in an aqueous environment was as expected, based on it being representative of the chemical class of lithium soaps. The significant surface-active properties presented by the test item resulted in the formation of colloidal (< 0.2 µm) dispersion of excess, undissolved test item throughout the saturated solution. As this dispersed, excess, undissolved material could not be satisfactorily removed by either centrifugation of filtration techniques, it was not possible to isolate a genuine saturated aqueous solution of test item suitable for analysis and quantification.

Conclusions:

The water solubility of lithium isooctadecanoate could not be determined.

Executive summary:

An attempt was made to determine the water solubility of lithium isooctadecanoate in a GLP-compliant study following OECD guideline 105 (Envigo 2017). The study is considered relevant and reliable for use for this endpoint. No determination of water solubility was feasible for the test item. This was due to the test item, representative of the chemical class of lithium soaps, showing significant surface-active properties in an aqueous environment. When attempting to generate saturated solutions, a colloidal suspension (i.e. containing micelles < 0.2 µm) was formed. As this dispersed, excess, undissolved material could not be satisfactorily removed by either centrifugation or filtration techniques, it was not possible to isolate a genuine saturated aqueous solution of test item suitable for analysis and quantification.

Description of key information

No determination of water solubility was feasible for lithium isooctadecanoate. Testing is currently ongoing to confirm the conclusion.

Additional information

An attempt was made to determine the water solubility of lithium isooctadecanoate in a GLP-compliant study following OECD guideline 105 (Envigo 2017). The study is considered relevant and reliable for use for this endpoint. The behaviour of the test item in an aqueous environment was as expected, based on it being representative of the chemical class of lithium soaps. The significant surface-active properties presented by the test item resulted in the formation of colloidal (< 0.2 µm) dispersions of excess, undissolved test item throughout the saturated solution. As this dispersed, excess, undissolved material could not be satisfactorily removed by either centrifugation of filtration techniques, it was not possible to isolate a genuine saturated aqueous solution of test item suitable for analysis and quantification.