Registration Dossier

Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Testing was conducted between 29 April 2009 and 17 June 2009.
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 the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Date of Signature: 04/03/09 Date of Inspection: 19/08/08
Type of method:
HPLC method
Partition coefficient type:
octanol-water

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Sponsor's identification : PDE-28
Description : red powder
Purity : 97%
Batch number : 1RF-8017
Date received : 23 March 2009
Storage conditions : room temperature, in the dark

Study design

Analytical method:
high-performance liquid chromatography

Results and discussion

Partition coefficientopen allclose all
Type:
Pow
Partition coefficient:
> 3 160 000
Type:
log Pow
Partition coefficient:
> 6.5
Details on results:
Preliminary estimate:

Approximate solubility in n-octanol: <1.6 x 10-2 g/l
Approximate solubility in water: <6.7 x 10-3 g/l

Due to the limited solubility of the test material in both solvents, no valid preliminary estimate of the partition coefficient could be generated.

Any other information on results incl. tables

Definitive test:

Calibration:

The retention times of the deadtime and the retention times, capacity factors (k) and log10 Pow values for the reference standards are shown in the following tables:

Table 1:

Dead Time

Retention Time (mins)

Mean Retention Time (mins)

Injection 1

Injection 2

Thiourea

1.688

1.687

1.688

Table 2:

Standard

Retention Time (mins)

Mean Retention Time (mins)

Capacity Factor (k)

Log10k

Log10Pow

Injection 1

Injection 2

Benzene

3.014

3.013

3.014

0.786

-0.105

2.1

Toluene

3.931

3.932

3.932

1.330

0.124

2.7

Naphthalene

4.238

4.238

4.238

1.511

0.179

3.6

Phenanthrene

6.744

6.753

6.749

2.999

0.477

4.5

Triphenylamine

20.064

20.083

20.074

10.895

1.037

5.7

DDT

31.050

30.939

30.995

17.367

1.240

6.5

Partition coefficient of sample:

The retention times, capacity factors and log10 Pow values determined for the sample are shown in the following table:

Table 3:

Injection

Retention Time (mins)

Capacity Factor (k)

Log10k

Log10Pow

1

40.502

23.001

1.362

>6.50

2

40.414

22.949

1.361

>6.50

Overall log10Pow:      > 6.50
Partition coefficient: > 3.16 x 106

Discussion:

Substances having a log10Pow greater than 3 are regarded as having the potential to bioaccumulate in the environment.

Based on estimated dissociation constants for the test material, 12.5 and 8.8 for donation of protons and -5.1 and -6.5 for acceptance of protons respectively for the cyclic amide functional groups (Advanced Chemistry Development, Inc, pKa, version 8.03); no specific manipulation of the mobile phase pH away from approximately neutral was required to ensure that the test material was in a non-ionised form. However experience has shown that for test materials with significant electronegative functional groups, the HPLC method may systematically underestimate the partition coefficient of the test material at a neutral mobile phase pH. This has been attributed to secondary interactions with repulsive anionic charges originating from ionised residual silanol groups within the HPLC column stationary phase, which prevent true partitioning. Therefore, a nominal mobile phase pH of 3.0 was used, which although not altering the non-ionised state of the test material, eliminated the presence of these potentially interfering groups on the stationary phase, thus maximizing the accuracy of this estimation method. The limited solubility of the test material in n-octanol and water prevented direct determination of the partition coefficient by the shake-flask method.


Applicant's summary and conclusion

Conclusions:
The partition coefficient of the test material has been determined to be greater than 3.16XE6, log10 Pow > 6.50.
Executive summary:

Partition Coefficient:

Greater than 3.16 x 106, log10Pow > 6.50, using the HPLC method, Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008.