1,3'-Bipyridinium, 5'-[[4-[[4-[(1',2'-dihydro-6'-hydroxy-3,4'-dimethyl-2'-oxo[1,3'-bipyridinium]-5'-yl)azo]benzoyl]amino]phenyl]azo]-1',2'-dihydro-6'-hydroxy-3,4'-dimethyl-2'-oxo-, salt with 2-hydroxypropanoic acid (1:2)

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January from 19th 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

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:

-3.46

Temp.:

20 °C

pH:

4.18 - 4.29

Details on results:

The partition coefficient (Pow) was determined to be 0.0004 ± 0.0001 (95 % confidence interval) which corresponds to log Pow of - 3.46 using the shake flask method.
The nine log Pow values were within a range of ± 0.3 units and thus complied with the guidelines.

Calculated partition coefficient (Pow) and log Pow

Ratio of solvents (n-Octanol : Water)	Partition coefficient		Log Partition coefficient		pH conditions
	Pow	Mean	Log Pow	Mean	pH	Mean
10:01	0.0003	0.0003	-3.59	-3.48	4.18	4.18
	0.0004		-3.44		4.18
	0.0004		-3.42		4.19
05:01	0.0005	0.0005	-3.33	-3.32	4.27	4.28
	0.0005		-3.32		4.29
	0.0005		-3.33		4.27
20:01	0.0003	0.0003	-3.53	-3.56	4.2	4.21
	0.0003		-3.56		4.21
	0.0003		-3.59		4.21
Mean all±95% confidence interval	0.0004±0.0001	-	-3.46 ± 0.11	-	4.22 ± 0.04	-

Measured concentrations

Ratio of solvents (n-Octanol : Water)	Measured concentration in n-octanol phase (µg/ml)	Measured concentration in aqueous phase (µg/ml)	pH
10 : 1	0.002	8.84	4.18
	0.003	8.68	4.18
	0.003	8.77	4.19
Mean	0.003	8.76	4.18
RSD %	19	1	-
Measured quantity of test item (Mo; Mw)	0.12 µg	36.8 µg	-
Total nominal quantity of test item (Ms)	37.3 µg
Total quantity of test item (Mo+Mw) in the two-phase system	36.9 µg
Recovery	99 %
5 : 1	0.002	4.78	4.27
	0.002	4.69	4.29
	0.002	4.56	4.27
Mean	0.002	4.68	4.28
RSD%	3	2	-
Measured quantity of test item (Mo; Mw)	0.09 µg	36.0 µg	-
Total nominal quantity of test item (Ms)	37.3 µg
Total quantity of test item (Mo+Mw) in the two-phase system	36.1 µg
Recovery	97 %
20 : 1	0.005	15.4	4.20
	0.004	16.1	4.21
	0.004	16.4	4.21
Mean	0.004	16	4.21
RSD %	4	3	-
Measured quantity of test item (Mo; Mw)	0.19 µg	35.1 µg	-
Total nominal quantity of test item (Ms)	37.3 µg
Total quantity of test item (Mo+Mw) in the two-phase system	35.3 µg
Recovery	95 %

Conclusions:

log Pow: -3.46 at 20 °C and pH ca 4.22

Executive summary:

The partition coefficient of the test item was determined by shake flask method, according to the OECD testing guideline 107. The experiments were carried out applying volume ratios and quantities of the test substance depending on expected partition and the LOQ of the analytical method in both phases. The maximum concentration in either phase was not greater than 0.01 mol/l. Three parallel tests were carried out. In the first, the calculated volume ratio was applied, in the second, this ratio was divided by two and in the third, this ratio was multiplied by two. The test was performed at 20 ± 1 °C. Three replicates were carried out at all solvent ratios.

The partition coefficient (Pow) was determined to be 0.0004 ± 0.0001 (95 % confidence interval) at 20 °C and pH ca 4.22; the determined Pow corresponds to log Pow of - 3.46 using the shake flask method.

The nine log Pow values were within a range of ± 0.3 units and thus complied with the guidelines.

Conclusion

log Pow: -3.46 at 20 °C and pH ca 4.22

Description of key information

log Pow: -3.46 at 20 °C and pH ca 4.22

Key value for chemical safety assessment

Log Kow (Log Pow):

-1

at the temperature of:

20 °C

Additional information

OECD 107 - shake flask method

The value for the chemical safety assessment was set to the minimum accepted value of -1.