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partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Between 4 March 2009 and 29 May 2009
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Recently conducted GLP compliant study using the most recent test methods

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
EU Method A.8 (Partition Coefficient)
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC method
Partition coefficient type:

Test material

Details on test material:
- Name of test material (as cited in study report): JKY-214
- Physical state: white solid
- Analytical purity: No information
- Lot/batch No.: Y002E
- Expiration date of the lot/batch: No information
- Stability under test conditions: No information. Assumed stable due to no data to the contrary
- Storage condition of test material: room temperature in the dark
- Other:

Study design

Analytical method:
high-performance liquid chromatography

Results and discussion

Partition coefficient
log Pow
Partition coefficient:
Details on results:
The test material had a predicted disociation constant of 7.24 using ACD/I-Lab Web Service (ACD/ pKa 8.03). Therefore, the test was conducted at pH 5.5 to obtain the test material at its fully non-ionised state as specified in the guideline. As the test was conducted at pH 5.5, a correct was made to estimate the Pow at the environmentally relevent pH 7.

Any other information on results incl. tables

Preliminary estimate

The approximate solubility of the test material was determined to be <9.60 mg/l in n-octanol and <10.2 mg/l in water. As the test material is insoluble in both n-octanol and water an estimate of the partition coefficient based on approximate solubilities would be inaccurate and meaningless.

Definitive test


The retention times of dead time and retention times, capacity factors and Pow values are shown below

dead time  retention time (mins) injection 1

retention time (mins) injection 2

mean retention time (mins) 
Thiourea 2.343  2.343 

 standard  retention time (mins) injection 1 retention time (mins) injection 2   mean retention time (mins)  capacity factor (k) log10 Pow 
Benzonitrile  3.123  3.122   3.123  0.333  1.6
Benzene  4.846  4.841   4.844  1.07  2.1
Toluene  6.520 6.517   6.519  1.78  2.7
Naphthalene  8.016  8.017   8.017  2.42  3.6
Phenanthrene  15.356 15.351  15.354  5.55  4.5
DDT  48.657 48.668   48.663  19.8  6.5

Partition coefficient of sample

The retention times, capacity factors and log Pow values for the test sample were determined to be

 Injection  retention time (mins) capacity factor log10 k log10 Pow
7.330  2.129  0.328  3.37 
7.320  2.125  0.327  3.37 

Mean log10 Pow = 3.37

Correction for pH

The correction for pH was made using the formula Pow = Pow (5.5)/ 1 + 10(pH-pKa)

where Pow = corrected Pow; Pow (5.5) = HPLC estimate Pow; pKa = 7.24; pH = 7

Applicant's summary and conclusion

The partition coefficient of the test sample, corrected to the environmentally relevent pH 7 was determined to be 3.37
Executive summary:

The partition coefficient has been assessed using the HPLC method according to EU method A8 in compliance with GLP. The test system was calibrated using seven reference reagents of known partition coefficient. Measurements for the test material were recorded in duplicate and the partition coefficient calculated by reference to the calibration curve established from the reference solutions. As the substance was expected to dissociate at pH 7, the test was conducted at pH 5.5 and then corrected to the environmentally relevent pH 7. The partition coefficient was determined to be 3.37 at pH 7