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Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experiment start date - 18 March 2010; Experiment completion date - 16 April 2010; Study completion date - 08 June 2010.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

Identification: FAT 40851/A TE
Batch Number: TZ 5891 / BOP 02-09
Purity: 69.9 % all coloured components
Appearance: Orange powder
Expiry Date: July 31, 2014
Storage Conditions: At room temperature at about 20 °C

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

< -4

Temp.:

22 °C

pH:

>= 5.99 - <= 6.05

Remarks on result:

other: pH refers to the water solubility in an isolated system, pH is not applicable to octanol solubility test

Details on results:

The n-octanol solubility of test substance was determined to be <11.39 μg/mL, which is below the concentration of the smallest calibration point (multiplied with the dilution factor).
The water solubility of test substance at 20 °C was determined to be 88.3 g/L with a standard deviation of ± 11.3. The correlation coefficient r² for the calibration data was 0.9999 (optimum 1.0000).

Results obtained for the Solubility of test substance in n-Octanol

Initial Weight of Test Item [g]	n-Octanol added [mL]	Measured Concentration [µg/mL]	Dilution Factor	Solubility in n-Octanol [mg/L]	Mean [mg/L]
0.10	10	<1.139	10	<11.39	< 11.39
0.11	10	<1.139	10	<11.39

 

The tabulated values represent rounded results, which were obtained by calculation using the exact raw data.

Conclusions:

The partition coefficient, log Pow of test substance was calculated from the solubilities in n-octanol determined in the preliminary test and in water (taken from the main test) to be: log Pow < - 4

Executive summary:

Neither the HPLC-method according to OECD Guideline No. 117 nor the flask-shaking method according to OECD Guideline No. 107 were applicable for the determination of the partition coefficient of test substance. Thus, the log P_ow value for the test item was estimated from its solubility in n-octanol and in water as determined in accordance with OECD Guideline for Testing of Chemicals, No. 105, “Water solubility”; adopted July 27, 1995. In the present study, performed under GLP conditions, the n-octanol solubility of test substance was determined to be <11.39 μg/mL, which is below the concentration of the smallest calibration point (multiplied with the dilution factor). The value for the solubility in water was taken from the main test of the water solubility determination. Consequently, the partition coefficient (n-octanol/water) of test substance can be calculated as follows: log P_ow = log (<0.011 g/L / 88.30 g/L) = < -4.

Description of key information

The substance has a very low octanol-water partitioning coefficient that was estimated to be -4 based on the solubilities in water and octanol.

Key value for chemical safety assessment

Log Kow (Log Pow):

-4

at the temperature of:

22 °C

Additional information

Neither the HPLC-method according to OECD Guideline No. 117 nor the flask-shaking method according to OECD Guideline No. 107 were applicable for the determination of the partition coefficient of test substance. Thus, the log P_ow value for the test item was estimated from its solubility in n-octanol and in water as determined in accordance with OECD Guideline for Testing of Chemicals, No. 105, “Water solubility”; adopted July 27, 1995. In the present study, performed under GLP conditions, the n-octanol solubility of test substance was determined to be <11.39 μg/mL, which is below the concentration of the smallest calibration point (multiplied with the dilution factor). The value for the solubility in water was taken from the main test of the water solubility determination. Consequently, the partition coefficient (n-octanol/water) of test substance can be calculated as follows: log P_ow= log (<0.011 g/L / 88.30 g/L) = <-4