Disodium 7-[[2-(acetylamino)-4-[(5-chloro-2,6-difluoro-4-pyrimidinyl)amino]phenyl]azo]naphthalene-1,3-disulphonate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August from 21st to 23rd, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Remarks:

although the values recorded are outside of the applicability domain for the test method, the results can be considered as reliable and representative for the tested substance

Reason / purpose for cross-reference:

reference to other study

Remarks:

validation of analytical method

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted July 27, 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - Shake Flask Method)

Version / remarks:

31 May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7550 (Partition Coefficient, n-octanol / H2O, Shake Flask Method)

Version / remarks:

August 1996

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

< -2.1

Temp.:

20 °C

pH:

5.2 - 6.7

Details on results:

The measured concentration of test item in the n-Octanol phases was found to be < LOQ. The calculation of the partition coefficient (Pow) and thelog Pow was performed using the extrapolated test item concentration in the n-Octanol phases and using the LOQ as the test item concentration in n-Octanol.

The partition coefficient (Pow) was determined to be 0.0036 (calculated with extrapolated concentration values), using shake-flask method, corresponding to a log Pow of -2.45.
The partition coefficient (Pow) and log Pow calculated with the quantification limit of the method as the concentration of the test item in n-Octanol phase was 0.0083 and the related log Pow is -2.10.
In conclusion, the partition coefficient, Pow, is considered to be lower than 0.0083 and the related log Pow lower than -2.10.

Calculated (extrapolated) partition coefficient (Pow) and log Pow

Ratio of solvents (n-Octanol : Water)	Partition coefficient	Log Partition coefficient	pH
	Pow	log Pow
1:1	0.0033	-2.49	5.59
1:2	0.0044	-2.36	6.47
2:1	0.0032	-2.5	5.19
Mean all	0.0036	-2.45	5.75

Calculated partition coefficient (Pow) and log Pow  based on LOQ value

Ratio of solvents (n-Octanol : Water)	Partition coefficient	log Partition coefficient	pH
	Pow	Log Pow
01:01	0.0081	-2.09	5.59
01:02	0.0112	-1.95	6.47
02:01	0.0054	-2.27	5.19
Mean all	0.0083	-2.1	5.75

Results of the determination of test item concentrations

Ratio of solvents (n-Octanol:water)	Measured concentration of Test Item (µg/ml)		pH	Measured concentration of Test Item (µg/ml)
	In Aqueous phase	Mean		In n-Octanol phase*	Mean
1:1	5.70	5.72	5.92	0.015	0.016
	5.74			0.017
	5.87	5.79	5.8	0.021	0.022
	5.70			0.023
	5.59	5.68	6.13	0.018	0.018
	5.78			0.018
Mean	5.73		5.95	0.019
Measured test item µg	42.98		-	0.141
Total nominal quantity of test item	43.44 µg
Total quantity of test item	43.1 µg			Recovery: 99 %
1:2	4.02	4.09	6.9	0.018	0.017
	4.16			0.015
	4.12	4.1	6.75	0.018	0.019
	4.08			0.019
	4.22	4.21	6.57	0.017	0.019
	4.20			0.021
Mean	4.13		6.74	0.018
Measured test item µg	41.35		-	0.09
Total nominal quantity of test item	43.44 µg
Total quantity of test item	41.4 µg			Recovery: 95 %
2:1	8.65	8.57	5.27	0.026	0.026
	8.49			0.025
	8.42	8.49	5.22	0.026	0.028
	8.56			0.029
	8.72	8.69	5.07	0.03	0.029
	8.67			0.028
Mean	8.58		5.19	0.027
Measured test item µg	42.92		-	0.274
Total nominal quantity of test item	43.44 µg
Total quantity of test item	43.2 µg			Recovery: 99 %

Conclusions:

log Pow < -2.10 at 20 °C and pH 5.2 - 6.7

Executive summary:

The partition coefficient of the test item was determined using shake-flask method, in accordante with the method and procedures outlined into the OECD guideline 107. The concentration in the aqueous and octanol phases was determined by HPLC-UV validate method. On the basis of the preliminary assay, shake-flask method was evaluated as chosen.

In the first experiment, the calculated volume ratio was applied, in the second, this ratio is divided by two and in the third, this ratio is multiplied by two. Test temperature was 20 ± 1 °C. Three parallel tests were carried out at all solvent ratios in 15 ml centrifuge tubes. The test vessels were shaken by hand through 180 ° about its transverse axis, hundred times during five minutes.

An HPLC method using UV-VIS detection has been validated for the quantification of the test item in ultra-pure water and in n-octanol.

The procedure was found to be suitable for the analysis.

The partition coefficient (Pow) of the substance was determined to be lower than 0.0083 (log Pow < -2.10) at 20 °C and pH values varied between 5.2 and 6.7.

Conclusion

log Pow < -2.10 at 20 °C and pH 5.2 - 6.7.

Description of key information

log Pow < -2.10 at 20 °C and pH 5.2 - 6.7

Key value for chemical safety assessment

Log Kow (Log Pow):

-2.1

at the temperature of:

20 °C

Additional information

OECD 107 - shake-flask method