Sodium bis[N-(2-chlorophenyl)-2-[[2-hydroxy-5-(N-methylsulphamoyl)phenyl]azo]-3-oxobutyramidato(2-)]cobaltate(1-)

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 April 2015 - 24 April 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Lot: AT-0032668200

GLP compliance:

no

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

Pow

Partition coefficient:

148.1

Temp.:

20 °C

Remarks on result:

other: pH is not known

Details on results:

log Pow = 2.16

The partition coefficient n-octanol/water of the test item at 20°C, from the individual solubility in water and n-octanol, was determined to: POW= 148.1 and log Pow = 2.16

 Preliminary Visual Estimation of the n-octanol solubility:

100 mg of the test item were stirred with different amounts of n-octanol at room temperature and visually checked for any undissolved particles. According to this preliminary test the solubility of the test item in n-octanol is about 4000 mg/l (without correction of the purity).

Calculation of the partition coefficient log Pow from the preliminary tests:

The partition coefficient P ow may be estimated from the saturation concentrations in n-octanol and water by the following equation:

P_ow= c_soctanol /c_swater

s= saturation

With the data obtained from the experiments in chapter 3.5.1 (c_s= 4000 mg/l) and in the preliminary test (water solubility: cs = 31,8 mg/l) the partition coefficient was calculated as log P_OW= 2.1

Due to the fact, that the water solubility is nearby the LoQ, the partition coefficient n-octanol/water has to be estimated from the individual solubilities in water and n-octanol.

 

Table: Solubility of the test item –experiments A to D

Experiment	A	B	C	D (blank)
Amount of test item (mg)	500	500	500	--
Stirring time at 30°C (h)	24	48	72	72
Aliquot of the flasks (ml)	0.05/10	0.05/10	0.05/10	0.05/10
Measured concentration (μg/ml)	23.2	24.1	23.2	--
Solubility (g/l)	4.64	4.83	4.66	--

 

Table: Concentrations of the standards for recheck:

Standard	Measured concentration (μg/ml)	% Recovery
Solution C + 11.4 μg	34.4	99.4

 

The recovery of 99.4 % indicates a sufficient accuracy of the analytical method.

Calculation of the partition coefficient log Pow from the individual solubility in water and n-octanol:

By means of the flask method, the satuation concentration of the test item in n-octanol was determined to: 4710 mg/l.

By means of the flask method, the saturation concentration of the test item in water was determined to: 31.8 mg/l

 

Table: Calculation of the partition coefficient from the individual solubility in water and n-octanol:

P ow = cs octanol /cs water	P ow	log P ow
4710 mg/l / 31.8 mg/l	148.1	2.17

 

The partition coefficient n-octanol/water of the test item at 20 °C, from the individual solubility in water and n-octanol, was determined to: P_OW= 148.1 and log Pow = 2.16

Conclusions:

The partition coefficient n-octanol/water of FAT 20035/E at 20°C, from the individual solubility in water and n-octanol, was Pow = 148.1 and log Pow = 2.16.

Executive summary:

The purpose of the study was determination of the partition coefficient n-octanol / water of the test item FAT 20035/E according to the OECD guideline 107 using flask method. According to the preliminary test the solubility of the test item in n-octanol is about 4000 mg/l (without correction of the purity). So based on the study results, the partition coefficent n-octanol/water of FAT 20035/E at 20 °C, from the individual solubility in water and n-octanol, was determined to be: Pow = 148.1 and log Pow = 2.16.

Description of key information

The partition coefficient n-octanol/water of test substance at 20 °C, from the individual solubility in water and n-octanol, was determined to be: Pow = 148.1 and log Pow = 2.16.

Key value for chemical safety assessment

Log Kow (Log Pow):

2.16

at the temperature of:

20 °C

Additional information

The purpose of the study was determination of the partition coefficient n-octanol / water of the test item FAT 20035/E according to the OECD guideline 107 using flask method. According to the preliminary test the solubility of the test item in n-octanol is about 4000 mg/l (without correction of the purity). So based on the study results, the partition coefficent n-octanol/water of FAT 20035/E at 20°C, from the individual solubility in water and n-octanol, was determined to be:

Pow = 148.1

log Pow = 2.16