5',5'''-[ethylenebis(p-phenyleneazo)]bis[1',2'-dihydro-6'-hydroxy-4'-methyl-2'-oxo-1,3'-bipyridinium] dilactate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March from 06th to 08th, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

-2.47

Temp.:

20 °C

pH:

4

Details on results:

The partition coefficient (Pow) was determined to be 0.0035 ± 0.0009 (95 % confidence interval) at 20 °C and pH ca 4.
Quality criteria were met as values of log Pow derived from individual measurements fell within a range of ± 0.3 log units.

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
1:1	0.0036	0.003	-2.45	-2.53	4.00	3.99
	0.0028		-2.55		3.99
	0.0026		-2.59		3.97
1:2	0.0058*	0.0048	-2.23*	-2.33	3.88	3.85
	0.004		-2.40		3.83
	0.0055		-2.26		3.85
2:1	0.003	0.003	-2.52	-2.53	3.90	3.91
	0.0029		-2.54		3.90
	0.0023*		-2.64*		3.92
Mean all ±95 % confidence interval	0.0035±0.0009		-2.47		-

* sample preparation error, not used for the calculations

easured concentrations

Ratio of solvents (n-octanol:water)	measured concentration of test item (µg/ml)		pH	measured concentration of test item (µg/ml)
	aqueous phase	mean		n-octanol phase	mean
1:1	62.33	68.74	4	0.242	0.247
	75.16			0.251
	67.3	71.6	3.99	0.183	0.201
	75.91			0.218
	74.97	72.74	3.97	0.167	0.187
	70.52			0.208
Mean	71.03		3.99	0.211
Measured test item µg	532.73		-	1.586
Total nominal quantity of test item	511.60 µg
Total quantity of test item	534.3 µg			Recovery: 104 %
1:2	57.3	56.72	3.88	0.326	0.330*
	56.14			0.335
	59.91	55.55	3.83	0.223	0.223
	51.18			0.223
	47.39	50.54	3.85	0.286	0.278
	53.68			0.27
Mean	54.27		3.85	0.251
Measured test item µg	542.67		-	1.253
Total nominal quantity of test item	511.60 µg
Total quantity of test item	531.7 µg			Recovery: 104 %
2:1	111.47	108.21	3.9	0.347	0.326
	104.95			0.306
	104.44	105.08	3.9	0.321	0.305
	105.72			0.289
	122.35	120.41*	3.92	0.258	0.273*
	118.47			0.288
Mean	106.65		3.91	0.316
Measured test item µg	533.23		-	3.158
Total nominal quantity of test item	511.60 µg
Total quantity of test item	536.4 µg			Recovery: 105 %

* sample preparation error, not used for the calculations

Conclusions:

log Pow: -2.47 at 20 °C and pH ca 4

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 measurements were performed by a previously validated analytical method.

The partition coefficient (Pow) was determined to be 0.0035 ± 0.0009 (95 % confidence interval) at 20 °C and pH ca 4; the determined Pow corresponds to log Pow of - 2.47 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: -2.47 at 20 °C and pH ca 4

Description of key information

log Pow: -2.47 at 20 °C and pH ca 4

Key value for chemical safety assessment

Log Kow (Log Pow):

-2.47

at the temperature of:

20 °C

Additional information

OECD 107 - shake flask method