Registration Dossier

Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18/08/2008-17/10/2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of relevant results.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Schedule 1, Good Laboratory Practice Regulations 1999 (SI 1999/3106 as amended by SI 2004/0994)
Type of method:
shake-flask method to: flask method
Partition coefficient type:
octanol-water

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Analytical method:
high-performance liquid chromatography

Results and discussion

Partition coefficient
Type:
Pow
Partition coefficient:
0.007
Temp.:
21 °C
pH:
>= 8.3 - <= 8.6

Any other information on results incl. tables

 Preliminary estimate

Solubility in n-octanol: < 5.46 g/l
Solubility in water: > 242.227 g/l
Approximate Pow:  < 2.25 x 10-2
Log10Pow:  < -1.65

 Definitive test for 2-ethyl butyrate

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

Solution

Mean Area

Organic Phase

Aqueous Phase

Standard 1.01 mg/l

2.532 x 105

2.202 x 105

Standard 1.09 mg/l

2.762 x 105

2.422 x 105

Sample 1

1.902 x 104

1.152 x 105

Sample 2

1.649 x 104

1.189 x 105

Sample 3

1.101 x 104

1.227 x 105

Sample 4

1.407 x 104

1.216 x 105

Sample 5

9.032 x 103

1.161 x 105

Sample 6

1.145 x 104

1.145 x 105

Stock solution A

-

1.064 x 105

Stock solution B

-

1.192 x 105


The total weights (mg) and analysed concentration (mg/l) of the respective phases are shown in the following table:

Sample Number

Volume of stock solution (ml)

Volume of
water saturated n-octanol
(ml)

Total Weight (mg)*

Organic Phase

Aqueous Phase

Analysed Concentration (mg/l)

Weight (mg)†

Analysed Concentration (mg/l)

Weight (mg)†

pH

1

24

48

24.5

7.51

0.361

1.04 x 103

25.0

8.4

2

25

50

25.5

6.52

0.326

1.08 x 103

26.9

8.5

3

15

60

15.3

4.35

0.261

1.11 x 103

16.7

8.5

4

20

80

20.4

5.56

0.445

1.10 x 103

22.0

8.6

5

8

64

8.16

3.57

0.228

1.05 x 103

8.40

8.3

6

9

72

9.18

4.52

0.326

1.04 x 103

9.32

8.6

pH of n-octanol saturated water:          6.5
pH of stock solution:                            7.1
Temperature:                                       21.0 ± 0.5°C

The partition coefficient determined for each sample is shown in the following table:

Sample Number

n-Octanol/Water Volume Ratio

Partition Coefficient

Log10Pow

Mean Partition Coefficient

1

2:1

7.21 x 10-3

-2.14

6.63 x 10-3

2

6.06 x 10-3

-2.22

3

4:1

3.92 x 10-3

-2.41

4.49 x 10-3

4

5.05 x 10-3

-2.30

5

8:1

3.40 x 10-3

-2.47

3.88 x 10-3

6

4.37 x 10-3

-2.36

Mean Pow : 5.00 x 10-3log10Pow: -2.30           Powstandard deviation : 1.42 x 10-3


Definitive test for magnesium

The mean absorbance obtained for the standard, stock and sample solutions are shown in the following table:

Solution

Mean Absorbance

Organic Phase

Aqueous Phase

Blank

3.19 x 10-2

3.81 x 10-2

Standard 0.1 mg/l

0.131

0.133

Standard 0.2 mg/l

0.258

0.262

Standard 0.3 mg/l

0.304

0.311

Standard 0.4 mg/l

0.370

0.381

Standard 0.5 mg/l

0.484

0.479

Standard 0.6 mg/l*

0.492

0.466

Sample 1

0.146

0.352

Sample 2

0.120

0.321

Sample 3

0.125

0.316

Sample 4

0.142

0.326

Sample 5

0.121

0.328

Sample 6

0.176

0.295

Stock solution A

-

0.339

Stock solution B

-

0.329

*From analysis of the stock solution

†From analysis of the respective phase

*not used to form calibration curve due to inconsistent readings.

See attachments for graphs.

The total weights (mg) and analysed concentration (mg/l) of the respective phases are shown in the following table:

Sample Number

Volume of stock solution (ml)

Volume of
water saturated
n-octanol
(ml)

Total Weight (mg)*

Organic Phase

Aqueous Phase

Analysed Concentration (mg/l)

Weight (mg)†

Analysed Concentration (mg/l)

Weight (mg)†

1

24

48

1.90

0.111

5.33 x 10-3

84.8

2.03

2

25

50

1.98

8.44 x 10-2

4.22 x 10-3

75.0

1.88

3

15

60

1.19

8.90 x 10-2

5.34 x 10-3

73.5

1.10

4

20

80

1.58

0.107

8.56 x 10-3

76.8

1.54

5

8

64

0.633

8.49 x 10-2

5.43 x 10-3

77.3

0.618

6

9

72

0.712

0.143

1.03 x 10-2

67.3

0.605

Temperature:   21.0 ± 0.5°C

The partition coefficient determined for each sample is shown in the following table:

Sample Number

n-Octanol/Water Volume Ratio

Partition Coefficient

Log10Pow

Mean Partition Coefficient

1

2:1

1.31 x 10-3

-2.88

1.22 x 10-3

2

1.13 x 10-3

-2.95

3

4:1

1.21 x 10-3

-2.92

1.30 x 10-3

4

1.39 x 10-3

-2.86

5

8:1

1.10 x 10-3

-2.96

1.61 x 10-3

6

2.13 x 10-3

-2.67

Mean Pow : 1.38 x 10-3log10Pow: -2.86           Powstandard deviation : 3.83 x 10-4

Validation

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 2 mg/l for the 2-ethyl butyrate in n-octanol saturated water. This was satisfactory with a correlation coefficient of 0.999 being obtained.


*From analysis of the stock solution

†From analysis of the respective phase

Applicant's summary and conclusion

Conclusions:
The partition coefficient of the test material has been determined to be 5.00 x 10-3, log10 Pow, -2.30 based on 2-ethyl butyrate and 1.38 x 10-3, log10 Pow, -2.86 based on the magnesium.
Executive summary:

The Partition Coefficient of Magnesium bis(2 -ethyl butlyrate) was determined to be 5.00 x 10-3, log10Pow-2.30, based on 2-ethyl butyrate and 1.38 x 10-3, log10 Pow-2.86, based on the magnesium, using the shake-flask method, Method A8 of Commission Directive 92/69/EEC.