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Administrative data

water solubility
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report

Materials and methods

Test guideline
according to
EU Method A.6 (Water Solubility)
Principles of method if other than guideline:
Two deviations from method A.6. and OECD Test Guideline No 105:In preliminary test the initial amount of the substance was increased to 1.00 g on the basis of analytical experience. Water volumes have been increased at the same rate. The reason for the increase of the test substance amount was an expectation of high water solubility and dark solution. On the basis of earlier studies the higher volume of the solution gives better conditions for evaluation of preliminary test. The mixture of the test substance with water had the gel structure during the preliminary test. For determination of the more precise concentration of the mixture without the gel structure were added next two steps (addition of 40 and 70 mL of water).These deviations from methods have no negative impact on the study results.
GLP compliance:
yes (incl. certificate)
Type of method:
flask method

Test material

Test material form:
solid: particulate/powder

Results and discussion

Solubility of metal ions in aqueous media
Key result
Mean dissolved conc.:
> 10 g/L
Test conditions:
Three flasks were used for test. 20.0 g of the test substance was weighed into each one of three stoppered glass flasks. The volume of 200 mL of double distilled water was added into each of them. The glass vessels were tightly closed with glass stoppers and shaken in a shaking water bath at the temperature of 30°C within one, two and three days.After the shaking had been finished, the solutions were tempered down to 20°C ± 0.1°C for a short period. The mixtures had the gel structure and contained solid particles after 1 and 2 days of shaking. Only the mixture after three days of shaking (Fig. No. 1) had the gel structure but it seemed to be without solid particles. The contents of the vessels were centrifuged 20 minutes at 3000 rpm at the test temperature 20°C. After centrifugation, the gel structure with solid particles was in whole volume of the mixtures after 1 and 2 days of shaking. No clear aqueous phase was found. Mixture after three days of shaking (Fig. No. 1) had the gel structure and it seemed to be without solid particles, but it was not possible to assess presence of solid particles due to the gel structure.
Remarks on result:
not determinable
Details on results:
The results of the determination of the test substance solubility are presented below:During the preliminary test, it was found that the mixture had the gel structure in test substances content higher than 10 g/L (see. Fig. No. 1). The mixtures were after one, two and three days of shaking in water bath at 30°C shortly tempered down to 20 °C. After 20 min of centrifugation at 3000 RPM at 20°C it was found that the test substance particles did not settled down. The gel structure of the mixtures did not allow to separate the solid particles from the liquid.

Applicant's summary and conclusion

It is not possible to determine test substance water solubility by flask method. Gel structure of the solution doesn’t allow separation of solid particles from liquid. The solutions have the gel structure in content of test substance in water higher than 10 g/l.