Reaction product of D-Glucopyranoside, methyl; esterified with oleic acid, methyl ester

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-04-02 - 2015-06-02

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same 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)

Remarks:

The department of health of the government of the United Kingdom

Type of method:

flask method

Key result

Water solubility:

<= 7.68 mg/L

Conc. based on:

test mat. (dissolved fraction)

Loading of aqueous phase:

0.1 g/L

Incubation duration:

30 min

Temp.:

20 °C

pH:

ca. 6.1

Preliminary test

The preliminary estimate of the water solubility was 4.7 x 10^-3 g/L at 20.0 ± 0.5 °C for both of the loading rates. These had a

solution pH of 6.8 (0.1 mg/L) and 7.1 (1 g/L).

Definitive test

The mean total peak areas for the standard and sample solutions are shown in the following table:

Solution	Mean Peak Area
Standard 0.106 mg/L	7.466 x E^5
Standard 0.265 mg/L	1.345 x E^6
Standard 0.531 mg/L	3.265 x E^6
Standard 1.06 mg/L	5.080 x E^6
Standard 1.08 mg/L	6.257 x E^6
Standard 2.65 mg/L	1.194 x E^7
Standard 5.31mg/L	2.871 x E^7
Standard 7.96mg/L	3.531 x E^7
Standard 10.6 mg/L	5.614 x E^7
Matrix blank*	2.809 x E^5
Sample 1A	3.096 x E^6
Sample IB	2.999 x E^6
Sample 2A	3.839 x E^6
Sample 2B	3.683 x E^6
Sample3A	1.832 x E^7
Sample 3B	1.802 x E^7

*The area for the blank was not taken into account in the calculation of the sample results as it was considered not significant and was smaller than the lowest calibration standard used. Also, it may have been due to carry over from the 10.6 mg/L standard that preceded it.

The concentration (g/L) of test item in the sample solutions is shown in the following table:

Sample Number	Time Shaken at ~ 30 °C (hours)	Time Equilibrated at 20°C (hours)	Concentration (g/L)	Solution pH
1	24	24	<1.34 x 10^-3	6.1
2	48	24	< 1.66 x 10^-3	6.1
3	72	24	<7.68 x 10^-3	6.3

Overall concentration: ≤ 7.68 x 10^-3 g/L at 20.0 ± 0.5 °C

Discussion

As the test item was a liquid, it was concluded that the flask method would be the most suitable for determination of water solubility. The samples were shaken at a slow speed to minimize the emulsification that was expected.

On completion of the equilibration period, the samples were cloudy solutions with excess test item present. After filtering the samples were visually clear and colorless but had a definitive Tyndall beam effect.

The ions chosen for the analysis by mass spectrometry represented one of the main components of the test item and tallied with a representative structure as provided by the Sponsor; these ions were used to represent the test item as a whole with it being a complex mixture. The ions represented one of the peaks seen in the Partition Coefficient chromatography that gave a log₁₀ P_ow of approximately 7.

The peaks seen in the Partition Coefficient chromatography that had a log₁₀ P_ow of > 10 were not included in water solubility analysis; this was because their expected water solubility was significantly lower than for the component chosen. To demonstrate this, the calculated water solubility of one of the less soluble components was 2.8 x 10^-11 mg/L using WSKOW v1.42. In contrast, the calculated water solubility of the component used was 0.02 mg/L. Due to the ability of the test item to emulsify in water, these less soluble components would be proportionally more abundant than would be expected from their calculated water solubilities because removal of all the undissolved, excess test item was not possible. Even so, basing the water solubility analysis on the component chosen still gave a worst case scenario for the test item a whole.

The preliminary test utilized two loading rates; these gave the same result. Therefore, it was decided to use the lower loading rate for the definitive test.

The results for the three definitive test samples were not in close agreement. This was attributed to the test item emulsifying in water and the clean-up procedure not being able to remove the undissolved test item completely. Therefore, slight differences in the filter media, sampling procedure and shaking could contribute towards the extent to which the test item was dispersed and then the ability to clean it up. Although longer shaking times may contribute to the test item being more dispersed, it was considered that this was not intrinsic to a higher water solubility result; but rather increasing the result due to the inability to remove additionally emulsified test item. The test item being emulsified is also backed up by the chromatographic profiles which is the same for the standards and samples; if the test item detected was only due to that dissolved it would be expected that the earlier eluting peaks would be proportionally bigger than later peaks as they would be expected to be more water soluble.

In respect of this, and in agreement from the Sponsor, it was decided to use a limit value based on the highest sample result as a worst case scenario for the definitive test result.

Overall the test result represents the amount of test item that would dissolve for the majority of the components within the test item. As this test item is a complex mixture, it would be unfeasible to accurately assess all the components that it contains.

Conclusions:

Interpretation of results: slightly soluble (0.1 - 100 mg/L)
The water solubility of the test item has been determined to be ≤ 7.68 x E-3 g/L of solution at 20.0 ± 0.5 °C.

Executive summary:

The water solubility of the test item was determined using the flask method compatile with OECD Guideline 105 and EU Method A.6 in compliance with GLP. The samples were shaken at a slow speed for the definitive test to minimize the emulsification that was possible if shaken more vigorously. On completion of the equilibration period, the samples had excess test item present. After the cleanup of the sample, the solutions were visually clear and colorless but had a definitive Tyndall beam effect. The results for the three definitive test samples were not in close agreement due to the emulsifying properties of the test item. In respect of this it was decided to use a limit value based on the highest sample result as a worst case scenario for the definitive test result.

Conclusively, the water solubility of the test item has been determined to be equal or less than ≤ 7.68 x 10^-3 g/L of solution at 20.0 ± 0.5 °C.

Description of key information

The water solubility of the test item has been determined according to EU Method A.6 (Fox, 2015) to be ≤ 7.68 x 10E-3 g/L of solution at 20.0 ± 0.5 °C.

Interpretation of results: slightly soluble (0.1 - 100 mg/L)

Key value for chemical safety assessment

Water solubility:

7.68 mg/L

at the temperature of:

20 °C

Additional information

The water solubility of the test item was determined using the flask method compatible with OECD Guideline 105 and EU Method A.6 (Fox, 2015) in compliance with GLP. The samples were shaken at a slow speed for the definitive test to minimize the emulsification that was possible if shaken more vigorously. On completion of the equilibration period, the samples had excess test item present. After the cleanup of the sample, the solutions were visually clear and colorless but had a definitive Tyndall beam effect. The results for the three definitive test samples were not in close agreement due to the emulsifying properties of the test item. In respect of this it was decided to use a limit value based on the highest sample result as a worst case scenario for the definitive test result.

Conclusively, the water solubility of the test item has been determined to be equal or less than ≤ 7.68 x 10E-3 g/L (7.68 mg/L) of solution at 20.0 ± 0.5 °C.