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Physical & Chemical properties

Water solubility

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Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
GLP compliance:
no
Type of method:
flask method
Key result
Temp.:
20 °C
Remarks on result:
not determinable
Details on results:
A determination of the water solubility of the test item is not feasible, because the test item formed dispersions without any mechanical treatment.

Shake Flask

Observation

After the stirring period, no remaining undissolved test item was observable on the inner wall of the vessel. The aqueous phase showed a visible turbidity.

The centrifuged aliquots showed a slight, but visible, Tyndall effect. The analyzed water solubility was in the range of 2 – 3 g/L, which was far off the expected water solubility of this substance type and close to the application dose.

 

Result

This type of application procedure is not feasible; the test item forms dispersions, which are not separable via centrifugation as suggested by the guideline.

 

Slow Stirring

Observation

No undissolved test item remained on the glass plates, both samples appeared as homogenous, but showed a Tyndall effect.

 

Result

The usage of a slow stirring method is not feasible due to the forming of a colloidal dispersion.

 

Without Stirring

 

Observation

Most of the test item “vanished” after a standing time of only 5 h. After a longer standing time (6 days at the longest), both samples appeared as homogenous, but showed a Tyndall effect near the bottom of the vessel (approx. 1 cm height).

 

Result

The determination of the water solubility acc. to OECD 105 is not feasible due to the forming of a colloidal dispersion without mechanical treatment.

 

Conclusions:
A determination of the water solubility of the test item is not feasible, because the test item formed dispersions without any mechanical treatment.
Executive summary:

The water solubility was determined according to OECD 105 using the shake flask and slow stirring method. For the shake flask trials, in duplicate, approx. 50 mg of the test item was applied to the inner wall of a glass vial and 15 mL of purified water were added. The samples were stirred over 2 days. Afterwards, aliquots of each sample were centrifuged. The shake flask method was not feasible as the test item forms dispersions, which are not separable via centrifugation as suggested by the guideline. For the slow stirring trials ,in duplicate, approx. 0.25 g of the test item were given onto a glass plate which was placed into a 250 mL glass bottle. The vessels were carefully filled with 250 mL water and overnight magnetically stirred with the slowest agitation speed applicable. After the stirring time, the samples were observed and checked for possible Tyndall effects. The slow stirring method was not feasible due to the forming of a colloidal dispersion Based on the results, it can be concluded that the test item forms stable dispersions without any mechanical treatment (e.g. stirring or shaking). Therefore, the determination of the water solubility acc. to OECD 105 is not feasible for this substance due to the test item properties.

 

Endpoint:
water solubility
Data waiving:
study technically not feasible
Justification for data waiving:
other:

Description of key information

A determination of the water solubility of the test item is not feasible, because the test item formed dispersions without any mechanical treatment (reference 4.8 -2).

Key value for chemical safety assessment

Additional information

In accordance with REACH Annex XI section 2 the study cannot be conducted as a determination of the water solubility of the test item is not feasible, because the test item formed dispersions without any mechanical treatment.

The water solubility was determined according to OECD 105 using the shake flask and slow stirring method (reference 4.8-2). For the shake flask trials, in duplicate, approx. 50 mg of the test item was applied to the inner wall of a glass vial and 15 mL of purified water were added. The samples were stirred over 2 days. Afterwards, aliquots of each sample were centrifuged. The shake flask method was not feasible as the test item forms dispersions, which are not separable via centrifugation as suggested by the guideline. For the slow stirring trials ,in duplicate, approx. 0.25 g of the test item were given onto a glass plate which was placed into a 250 mL glass bottle. The vessels were carefully filled with 250 mL water and overnight magnetically stirred with the slowest agitation speed applicable. After the stirring time, the samples were observed and checked for possible Tyndall effects. The slow stirring method was not feasible due to the forming of a colloidal dispersion Based on the results, it can be concluded that the test item forms stable dispersions without any mechanical treatment (e.g. stirring or shaking). Therefore, the determination of the water solubility acc. to OECD 105 is not feasible for this substance due to the test item properties.