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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
August 1987 to February 1988
Reliability:
1 (reliable without restriction)
Reason / purpose for cross-reference:
reference to same study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
The method used in the report has been described by Eadsforth, 1982 - Eadsforth, CV (1982) - The development of an HPLC analytical method for the determination of partition coefficients.
GLP compliance:
yes
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
7.4
pH:
6.9

Note: The log n-octanol/water partition coefficient value of the testing substance was also determined by calculation from chemical structure. The model used was the fragment addition method of . Then, the program MEDCHEM (current software revision 3.32) installed on the VAX computer was used for this purpose.

Hansch, C and Leo, A (1979) Substituent constants for correlation analysis in chemistry and biology , J. Wiley and Sons, New York, 352 pp.

The result was log Pow = 10.9

Conclusions:
The determination of log Pow of the testing substance (4,4'-methylene-bis-2,6-di-tert-butyl phenol) by reverse-phase HPLC has shown that the value is quite high (7.4) or probably even higher, which may indicate that the bioavalability may be limited and the bioaccumulation potential moderate.
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
10 February 2005-18 March 2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline Study
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: ASTM E1147-92
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
Pow
Partition coefficient:
> 3 160 000
Remarks on result:
other: Details on pH and temperature are not reported
Type:
log Pow
Partition coefficient:
> 6.5
Remarks on result:
other: Details on pH and temperature are not reported

Results:

Preliminary estimate

Approximate solubility in n-octanol: 16.7 g/L

Approximate solubility in water: <5.00 x 10-3g/L

Approximate Pow: >3.33 x 103

Log10Pow: >3.52

Definitive test

Calibration:

The retention times of thiourea and the retention times, capacity factors (k) and log10Powvalues for the reference standards are shown in the following tables:

Dead Time

Retention Time (mins)

Mean Retention Time (mins)

Injection 1

Injection 2

Thiourea

2.864

2.860

2.862

Standard

Retention Time (mins)

Mean Retention Time (mins)

Capacity Factor (k)

Log10k

Log10Pow

Injection 1

Injection 2

Acetanilide

3.630

3.628

3.629

0.268

-0.572

1.16

Benzene

6.235

6.231

6.233

1.18

7.11

2.1

Toluene

8.592

8.586

8.589

2.00

0.301

2.7

Naphthalene

10.898

10.888

10.893

2.81

0.448

3.6

Phenanthrene

22.596

22.564

22.580

6.89

0.838

4.5

Triphenylamine

49.321

49.407

49.364

16.2

1.21

5.7

DDT

69.050

69.252

69.151

23.2

1.37

6.5

Partition coefficient of sample

The retention times, capacity factors and log10Powvalues determined for the sample are shown in the following table:

Injection

Retention Time (mins)

Capacity Factor (k)

Log10k

Log10Pow

1

99.910

>23.2

>1.37

>6.50

2

99.914

>23.2

>1.37

>6.50

Mean log10Pow:           >6.50

Partition coefficient:           >3.16 x 106

A calculated value of partition coefficient gave a log10Powresult of 8.99.

Conclusions:
the partition coefficient of the test material has been determined to be greater than 3.16 x 10^6, log10 Pow > 6.50. A calculated estimation of partition coefficient gave a log10Pow result of 8.99.
Executive summary:

Partition coefficient of greater the 3.16 x 106and log10Pow> 6.5, using HPLC method:

* Method A8 of Commission Directive 92/69/EEC.

* Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

* Method 830.7570 of the OPPTS Guidelines.

* ASTM E1147-92.

A calculated estimation of partition coefficient gave a log10Powresult of 8.99.
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Equivalent to OECD 117. No data on GLP.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Deviations:
no
GLP compliance:
not specified
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
7.4
pH:
6.9
Remarks on result:
other: Details on pH and temperature are not reported
Details on results:
No data provided on the test temperature.

The log Pow value was also calculated from chemical structure using the fragment-addition method of Hansch and Leo (1979). The calculated value is 10.9.

Conclusions:
The value obtained by HPLC was 7.4 and by calculation 10.9.
Executive summary:

The log n-octanol/water partition coefficient value of the test substance was determined by both reverse phase HPLC and by calculation from chemical structure. The value obtained by HPLC was 7.4 and by calculation 10.9.

Description of key information

Experimental results: OECD 117, GLP. The log n-octanol/water partition coefficient value of the test substance was determined by both reverse phase HPLC and by calculation from chemical structure. The value obtained by HPLC was > 6.5 and by calculation 8.99

Key value for chemical safety assessment

Log Kow (Log Pow):
8.9
at the temperature of:
25 °C

Additional information

Key study: Experimental results: OECD 117, GLP. The log n-octanol/water partition coefficient value of the test substance was determined by both reverse phase HPLC and by calculation from chemical structure. The value obtained by HPLC was > 6.5 and by calculation 8.99. Extrapolation of the HPLC-curve indicates that it is likely that the calculated value is correct.