Registration Dossier

Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Cross-reference
Reason / purpose:
read-across source
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:
EU Method A.6 (Water Solubility)
Version / remarks:
2008
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Version / remarks:
1995
Deviations:
no
GLP compliance:
not specified
Type of method:
flask method
Key result
Water solubility:
259.9 g/L
Conc. based on:
test mat.
Temp.:
20 °C
pH:
>= 6.5 - <= 6.6

Preliminary test

The preliminary test at room temperature showed that the water solubility of the test item was between 27.1 g/L and 61.0 g/L. The observations of the preliminary test are summarized below:

Table: Preliminary test for the water solubility

Amount of test item [mg]

Total volume of added water [mL]

Stirring time [min]

Remark

97.6

0.1

--

Not dissolved

0.6

--

Not dissolved

1.6

--

Not dissolved

3.6

--

Dissolved

The solubility of the test item in water at room temperature was estimated to be > 27.1 g/L and < 61.0 g/L. Therefore, the flask method was performed.

Main test (flask method)

For the main test three flasks were prepared with an amount of test item and water, and one flask only with water. After stirring and centrifugation the aqueous phases were measured by means of HPLC. The solution of each flask was measured twice. The results of these measurements are shown below:

Table: Results of the flask method

Flask

1b

2a

3a

4a (blank)

Measured value [mg/L]

58.56 / 57.80

60.14 / 60.74

58.64 / 59.22

0 / 0

Aliquot of the flask [mL]

0.1

0.1

0.1

0.1

Total volume after 1stdilution [mL]

100

100

100

100

Aliquot of the 1stdilution [mL]

0.2

0.2

0.2

0.2

Total volume after 2nddilution [mL]

1

1

1

1

Water solubility [g/L]

292.8 / 289.0

300.7 / 303.7

293.2 / 296.1

0 / 0

Average water solubility [g/L]

290.9

302.2

294.6

0

Mean value of the water solubility [g/L]

259.9

0

Standard deviation [g/L]

5.8

--

Relative standard deviation [%]

2.0

--

The values represented in the table are rounded values. The calculation was carried out with the original not rounded values.

 

To verify the accuracy of the analytical method a fresh prepared standard solution (prepared with the test item) was measured in between the samples of the flask method. The results of these measurements are shown below:

Table: Measurement of standard solution

Standard solution (nominal value [mg/L]

Measured value [mg/L]

Repeatability [%]

Ü-1 (57.0)

58.5

102.6

52.4

91.9

58.0

101.7

Ü-2 (80.0)

79.0

98.7

80.6

100.7

77.2

96.5

79.1

98.9

 

The recovery rate of the measured standard solutions was in the range from 91.9 % to 102.6 % which shows a good accuracy of the analytical method.

Final results

According to OECD Test Guideline 105 (1995) and Regulation EC No. 440/2008 Method A.6., the water solubility at 20 °C of the test item is as follows:

cS= 259.9 g/L

RSD = 2.0 %

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient - Shake Flask Method)
Version / remarks:
estimation method according Appendix 1 of EU Method A.8
Deviations:
no
Qualifier:
according to
Guideline:
other: OECD 105
Version / remarks:
The solubility of the substance in n-octanol was determined with flask method according to OECD Guideline 105
GLP compliance:
not specified
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
octanol-water

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline

Study design

Analytical method:
high-performance liquid chromatography

Results and discussion

Partition coefficient
Key result
Type:
log Pow
Partition coefficient:
< -3.1
Temp.:
20 °C
Remarks on result:
other: pH not reported

Any other information on results incl. tables

Preliminary tests

The preliminary test at room temperature showed that the n-octanol solubility of the test item seemed to be below 0.2 g/L. The observations of the preliminary test are summarized in the below table:

Table: Preliminary test for the n-octanol solubility

Amount of test item [mg]

Total volume of added octanol [mL]

Stirring time at RT [h]

Remark

124.0

10

0.7

Not dissolved

60

18

Not dissolved

19.9

100

23

Not dissolved

With the estimated values of the water solubility determined in the preliminary test in project CSL-17 -1555.03 (27.1 to 61.0 g/L of the test item) and the estimated solubility in n-octanol from this preliminary test, the partition coefficient can be estimated to be below -2.0.

For the determination of the log Pow in this range the determination of the solubilities in water and n-octanol is recommended.

Thus, the determination of the log Pow was carried out by determining the solubility in n-octanol by means of the flask method, which is also used for the determination of the water solubility.

Main Test (flask method)

For the main test three tasks were prepared with an amount of test item an n-octanol, and one flask only with n-octanol. From these solutions, DAD-spectra were measured in the HPLC. Both spectra showed a similar absorption with a maximum at approx. 630 nm.

The mixtures in the flasks were stirred for 24 to 72 h at 30 °C and subsequently for 24 h at 20 °C. After the test the colour of the solutions changed to brown and the solutions were centrifuged. It was observed that the test solutions showed a different absorption spectrum, in which the maximum at 630 nm did not exist anymore.

It seemed that the test item reacted with n-octanol to another substance which showed a different absorption spectrum. Thus, an analytical determination of the concentration of the test item was not possible and the solubility of the test item in n-octanol could not be determined quantitatively.

Final results

In accordance with Regulation EC No. 440/2008 Method A.8. and OECD 105, the partition coefficient at 20 °C of the test item was estimated from the solubility in water of 259.9 g/L, and the solubility in n-octanol of <0.2 g/L, which was determined in the preliminary test of this study, to be:

Pow < 7.70 x 10-4

log Pow < -3.1

Applicant's summary and conclusion