Tetrasodium 2-[[8-[[3-[(5-chloro-2,6-difluoro-4-pyrimidinyl)amino]benzoyl]amino]-1-hydroxy-3,6-disulphonato-2-naphthyl]azo]naphthalene-1,5-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:

June from 27 to 29, 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Remarks:

although the log Pow value resulted to be out of the method applicability domain, the results can be considered as appropriate and well representative for the test substance characteristic

Reason / purpose for cross-reference:

reference to other study

Remarks:

validated 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

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:

< -2.46

Temp.:

20 °C

pH:

6 - 6.4

Type:

Pow

Partition coefficient:

< 0.004

Temp.:

20 °C

pH:

6 - 6.4

Details on results:

The partition coefficient (Pow) was determined to be 0.0021 (calculated with extrapolated concentration values) using shake-flask method. The log Pow is -2.74.
The partition coefficient (Pow) and log Pow calculated with the quantification limit of the method (taking into consideration the four-fold sample concentration step) as the concentration of the test item in n-Octanol phase was 0.0036, and the log Pow is -2.46.
The measured concentration of test item in the n-Octanol phases was found to be < LOQ. The partition coefficient (Pow) and log Pow was calculated using the extrapolated test item concentration in the n-Octanol phases. The calculation of partition coefficient (Pow) and log Pow was carried out using the LOQ (taking into consideration the four-fold sample concentration step) as the test item concentration in n-Octanol.

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

Ratio of solvents (n-Octanol : Water)	Partition coefficient (Pow)	log Partition coefficient (log Pow)	pH
1 : 1	0.0019	-2.72	6.39
1 : 2	0.0034	-2.47	6.07
2 : 1	0.0009	-3.03	6.00
Mean all	0.0021	-2.74	-

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

Ratio of solvents (n-Octanol : Water)	Partition coefficient (Pow)	log Partition coefficient (log Pow)	pH
1 : 1	0.0036	-2.44	6.39
1 : 2	0.0048	-2.32	6.07
2 : 1	0.0023	-2.63	6.00
Mean all	0.0036	-2.46	-

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
	In Aqueous phase	Mean		In n-Octanol phase*	Mean
1 : 1	3.49	3.49	6.40	0.006	0.006
	3.49			0.007
	3.5	3.50	6.49	0.007	0.007
	3.5			0.007
	3.39	3.40	6.27	0.006	0.006
	3.41			0.006
Mean	3.46		6.39	0.007
Measured test item µg	25.97		-	0.05
Total nominal quantity of test item	22.77 µg
Total quantity of test item	26.0 µg			Recovery: 114 %
1 : 2	2.59	2.60	6.11	0.008	0.008
	2.61			0.009
	2.65	2.63	6.03	0.009	0.009
	2.62			0.009
	2.60	2.61	6.08	0.009	0.009
	2.61			0.009
Mean	2.61		6.07	0.009
Measured test item µg	26.12		-	0.044
Total nominal quantity of test item	22.77 µg
Total quantity of test item	26.2 µg			Recovery: 115 %
2 : 1	5.31	5.30	6.03	0.005	0.005
	5.29			0.005
	5.29	5.29	6.00	0.005	0.005
	5.28			0.005
	5.38	5.38	5.98	0.005	0.005
	5.38			0.005
Mean	5.32		6.00	0.005
Measured test item µg	26.61		-	0.05
Total nominal quantity of test item	22.77 µg
Total quantity of test item	26.7 µg			Recovery: 117 %

Conclusions:

log Pow < -2.46 at 20 °C and pH between 6 -6.4

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, the value of the partition coefficient was estimated from the ratio of the solubility of the test item in the pure solvents; since the log Pow value was estimated to be between -2 and 4, the shake-flask method was chosen for the main test.

In the main experiment, three experiments were carried out applying different solvent ratios. 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.

The measured concentration of test item in the n-Octanol phases was found to be < LOQ, thus, the partition coefficient (Pow) and log Pow were calculated using the extrapolated test item concentration in the n-Octanol phases; the LOQ (taking into consideration the four-fold sample concentration step) was considered as the test item concentration in n-Octanol.

The partition coefficient (Pow) was determined to be 0.0021 (calculated with extrapolated concentration values) using shake-flask method; the log Pow is -2.74. 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 0.0036, and the log Pow is -2.46.

Conclusion

log Pow < -2.46 at 20 °C and pH between 6 -6.4

Description of key information

log Pow < -2.46 at 20 °C and pH between 6 -6.4

Key value for chemical safety assessment

Log Kow (Log Pow):

-2.46

at the temperature of:

20 °C

Additional information

OECD 107 - Shake-flask method