Registration Dossier

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
10 Jan - 27 Jan 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Partition coefficient of the test item was calculated based in the ratio of its water solubility and its octanol solubility (based on OECD 105).
Qualifier:
according to
Guideline:
other: OECD 105 (Flask Method for Determination of octanol solubility)
Version / remarks:
adopted in 2008
GLP compliance:
no
Type of method:
calculation method (fragments)
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
Storage conditions: Ambient temperature (10 to 30 °C), dry
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
-4.7
Temp.:
20 °C
Remarks on result:
other: pH not measured

Results
Table 1 – Preliminary visual estimation of n-octanol solubility

Amount of test item [mg]

Added volume of n-octanol [mL]

Total volume of n-octanol [mL]

Stirring time [h]

Appearance of mixture

26.6

2

2

~ 0.7

Not dissolved

8

10

~ 0.8

90

100

~ 18

 

The solubility of the test item in n-octanol was: csn-octanol< 266 mg/L (without correction for the purity).

Calculation of Partition Coefficient from Preliminary Test
The calculation was done with the result of the preliminary estimation of water solubility determined in the study report of reference 4.8 -1, i.e. cswater> 95.3 g/L and the csn-octanolvalue above. It was calculated to be: log POW< -2.6.

The calculated value obtained from KOWWIN (part of EPI Suite) was log POW= -4.9.


Due to the calculations, the partition coefficient was estimated based on the ratio of the solubilities in water and octanol.

Determination of solubility in n-octanol – Flask Method
The n-octanol solubility was calculated from the measured and unrounded concentration values (not from the rounded values given in table 2).

Table 2 – n-octanol Solubility Experiments of the Test Item

Experiment

24 h experiment

48 h experiment

72 h experiment

Blank experiment (72 h)

Test item amount [mg]

66.8

67.7

67.2

--

Octanol amount [mL]

50

 

Stirring time at 30 °C [h]

24

48

72

72

Dilution factor

25

Measured concentration [mg/L]

0.123/0.138

0.152/0.143

0.144/0.145

--/--

Mean concentration [mg/L]

0.130

0.148

0.144

--

n-octanol solubility [g/L]

0.0033

0.0037

0.0036

--

 

The n-octanol solubility of the test item at 20 °C was determined to be 0.0035 g/L.

Calculation of Partition Coefficient from Individual Solubilities
In the study report in reference 4.8 -1, the water solubility of the test item at 20 °C was cswater= 176 g/L (± 2 g/L). Thus, the partition coefficient was calculated to be:

log POW= -4.7

 

Description of key information

log POW = -4.7 at 20 °C (EU Method A.8., Calculation method)

Key value for chemical safety assessment

Log Kow (Log Pow):
-4.7
at the temperature of:
20 °C

Additional information

Partition coefficient was determined based on the ratio of the individual solubilities of the test item in water and octanol. The individual octanol solubility was determined using the flask method (OECD 105).