Registration Dossier

Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
21 May 2008 and 02 June 2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

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

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
The work described was performed in compliance with UK GLP standards (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:
photometric method

Results and discussion

Partition coefficient
Type:
log Pow
Partition coefficient:
-1.26
Temp.:
22.4 °C
pH:
ca. 7

Any other information on results incl. tables

                    Results

                 Preliminary estimate

Approximate solubility in n-octanol: 0.138 g/l
Approximate solubility in water:       > 31.1 g/l
Approximate Pow:   <4.42 x 10-3
Log10 Pow:   <-2.36

             Definitive test

The absorbances obtained for the standard, stock and sample solutions are shown in the following two tables:

Organic Phase

Solution

Absorbance

Standard 25.9 mg/l

0.80004

Standard 27.1 mg/l

0.84852

Organic phase matrix blank

None detected

Sample 1

1.3736

Sample 2

1.4024

Sample 3

1.2087

Sample 4

1.2227

Sample 5

1.0571

Sample 6

1.0769

– Aqueous Phase

Solution

Absorbance

Standard 30.2 mg/l

1.0255

Standard 30.0 mg/l

1.0181

Aqueous phase matrix blank

None detected

Sample 1

1.0118

Sample 2

1.0100

Sample 3

0.97802

Sample 4

0.97650

Sample 5

0.91917

Sample 6

0.90633

Stock solution A

1.0358

Stock solution B

1.0483

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

Sample Number

Volume of water saturated

n-octanol (ml)

Volume of stock solution (ml)

Total Weight (mg)*

Organic Phase

Aqueous Phase

Analysed Concentration (mg/l)

Weight (mg)†

Analysed Concentration (mg/l)

Weight (mg)†

pH

1

75

75

115

88.3

6.62

1.49 x 103

112

7.2

2

70

70

108

90.1

6.31

1.49 x 103

104

7.4

3

100

50

76.8

77.7

7.77

1.44 x 103

72.1

7.5

4

100

50

76.8

78.6

7.86

1.44 x 103

72.0

7.5

5

128

32

49.1

67.9

8.69

1.36 x 103

43.4

8.0

6

112

28

43.0

69.2

7.75

1.34 x 103

37.4

8.0

pH of n-octanol saturated water:           6.7
pH of stock solution:                             7.1
Temperature:                                        22.4 ± 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

Log10 Pow

Mean Partition Coefficient

1

1:1

5.92 x 10-2

-1.23

5.99 x 10-2

2

6.05 x 10-2

-1.22

3

2:1

5.39 x 10-2

-1.27

5.42 x 10-2

4

5.46 x 10-2

-1.26

5

4:1

5.01 x 10-2

-1.30

5.10 x 10-2

6

5.18 x 10-2

-1.29

Mean Pow : 5.50 x 10-2              log10 Pow : -1.26                        Pow standard deviation : 4.09 x 10-3


* From analysis of the stock solution

† From analysis of the respective phase

Validation

Linearities of the detector response with respect to concentration were assessed over the nominal concentration ranges of 0 to 50 mg/l (for the organic phases) and 0 to 60 mg/l (for the aqueous phases).  These were satisfactory with correlation coefficients of 0.996 and 1.00 being obtained respectively.

Discussion

Substances having a log10 Powof greater than 3 are regarded as having the potential to bioaccumulate in the environment.

The test was carried out using unadjusted n-octanol saturated water, at ~ pH 7 (as recommended for salts).

Conclusion

The partition coefficient of the test material has been determined to be 5.50 x 10-2 at 22.4 ± 0.5°C, log10Pow -1.26.

Applicant's summary and conclusion

Conclusions:
The partition coefficient of the test material has been determined to be 5.50 x 10-2 at 22.4 ± 0.5°C, log10 Pow -1.26.
Executive summary:

The determination was carried out using the shake-flask method, Method A8 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

The partition coefficient of the test material has been determined to be 5.50 x 10-2 at 22.4 ± 0.5°C, log10 Pow -1.26.