1,3,6-Naphthalenetrisulfonic acid, 7-[2-[2-[(aminocarbonyl)amino]-4-[[4-chloro-6-[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]amino]-1,3,5-triazin-2-yl]amino]phenyl]diazenyl]-, sodium salt

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 October 2006 to 23 November 2006

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

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

-6.4

Temp.:

20 °C

Remarks on result:

other: pH not specified in the report

Details on results:

The partition coefficient n-octanol/water of the test item at room temperature, performed according to the flask method (individual solubilities in water and n-octanol}, was determined to:
log Pow -6.4

Preliminary Visual Estimation of the n-Octanol Solubility: Amounts of the test item were stirred with different amounts of n-octanol at room temperature.

Table 1: Appearance of the test mixtures

Amount of the test item in mg	Total volume in ml	Stirring time in min	Appearance of mixture	Solubility in g/l
228.8	4	50	Undissolved
	8	30	Undissolved
	18	35	Undissolved
	28	45	Undissolved
	48	40	Undissolved
	68	150	Undissolved
	118	1050	Undissolved
25.4	13	45	Undissolved
	33	30	Undissolved
	73	65	Undissolved
	123	110	Undissolved
	173	50	Undissolved	< 0.15
	273	95	Dissolved	> 0.09

According to this preliminary test the solubility of the test item in n-octanol is between 0.09 g/l and 0.15 g/l (without correction for the purity).

 

Calculation of the Partition coefficient log P_owfrom the preliminary tests: The partition coefficient P_owmay be estimated from the saturation concentrations in n-octanol and water by the following equation:

P_ow= c_S^octanol/ c_S^water

S = saturation

 

With the data obtained from the experiments the partition coefficient was calculated as log P_ow-2. Due to this fact the partition coefficient n-octanol/water of the test item at ambient temperature had to be estimated from the individual solubilities in water and octanol.

 

Calculation of the Partition Coefficient P_owfrom the Individual Solubilities: The saturation concentration of the test item in water was determined by means of the flask method in project 20060734.01 to 396.7 g/l (without correction for the purity).

 

Table 2: Octanol solubility of the test item – experiments A to D

Experiment	A	B	C	D (blank)
Amount of test item (g)	0.83	0.81	0.81	--
Stirring time at 20°C (h)	24	24	24	24
Aliquot (ml)	1	1	1	1
End volume (ml)	1	1	1	1
Measured concentration (mg/l)	<0.16 / <0.16	<0.16 / <0.16	<0.16 / <0.16	<0.16 / <0.16
Mean concentration (mg/l)	<0.16 / <0.16	<0.16 / < 0.16	<0.16 / <0.16	< 0.16 / <0.16
Octanol solubility (mg/l)	<0.16	<0.16	<0.16	<0.16

Average experiments A to C (without correction for the purity): <0.16 mg/l

From the individual solubilities thelog P_owcan be calculated to-6.39.

 

Table 3: Concentrations of standards for recheck:

Standard	Measured concentration (mg/l)	% Recovery (mean value)
Standard 9 ( c = 85.1 mg/l)	82.1 – 82.6	96.8
Standard 8 (c = 106.4 mg/l)	103.4 / 103.4	97.2

Recoveries of the recheck samples ranged from 96.8% to 97.2%, indicating a good accuracy of the analytical method.

Conclusions:

The partition coefficient n-octanol/water of the test item at room temperature, performed according to the flask method (individual solubilities in water and n-octanol}, was determined to:
log Pow -6.4

Executive summary:

The objective of this study was the determination of the partition coefficient n-octanol/water of the test item according to the consolidated version of Guideline 67/548/EEC Annex V (Council Directive 92/69/EEC), PartA:Methods for determination of physico-chemical properties.A.8.partition coefficient n-octanol/water and OECD test guidelines, OECD 107 ( 1995), partition coefficient n-octanol/water. The study was performed in accordance with the Principles of Good Laboratory Practice (GLP) and reported with a valid GLP certificate.

 

The saturation concentration of the test item in water was estimated with the preliminary test in project 20060734.01 to be between 510 g/l and 610 g/l (without correction of the purity).

 

Preliminary Estimation of the n-Octanol Solubility: Two amounts of the test item were stirred at room temperature with increasing volumes of n-octanol. Due to the fact that the estimated log P_owwas below -2, the partition coefficient n-octanol/water of the test item at room temperature had to be determined by the flask method.

 

Individual Solubilities in water and n-octanol: The saturation concentration of the test item in water was determined by means of the flask method in project 20060734.01.

The saturation concentration of the test item in n-octanol was also determined by means of the flask method:

Three flasks were prepared with about 0.8 g of the test item and 50 ml n-octanol. The batches were stirred for 24 h at 20°Cin tightly closed flasks. Parts of the saturated octanol phases were centrifuged (30 minutes, 20°C,15000 rpm). Another experiment was performed according to this procedure but without test item ("blank"= H).

 

With the data obtained from the experiments the partition coefficient was calculated as logP_ow-2. Due to this fact the partition coefficient n-octanol/water of the test item at ambient temperature had to be estimated from the individual solubilities in water and octanol.

The saturation concentration of the test item in water was determined by means of the flask method in project 20060734.01 to 396.7 g/l (without correction for the purity). Average experiments A to C (without correction for the purity): <0.16 mg/L

From the individual solubilities the log Pow can be calculated to-6.39.

 

The partition coefficient n-octanol/water of the test item at room temperature, performed according to the flask method (individual solubilities in water and n-octanol), was determined to: log Pow -6.4

Description of key information

The partition coefficient n-octanol/water of the test item at room temperature, performed according to the flask method (individual solubilities in water and n-octanol), was determined to: log Kow -6.4

Key value for chemical safety assessment

Log Kow (Log Pow):

-6.4

at the temperature of:

20 °C

Additional information

The partition coefficient n-octanol/water of the test item was determined according to methods A.8.partition coefficient n-octanol/water and OECD test guidelines, OECD 107 ( 1995), partition coefficient n-octanol/water. The saturation concentration of the test item in water was estimated with the preliminary test in project 20060734.01 to be between 510 g/l and 610 g/l (without correction of the purity).

The saturation concentration of the test item in n-octanol and water was determined by means of the flask method. Three flasks were prepared with about 0.8 g of the test item and 50 ml n-octanol. The batches were stirred for 24 h at 20°C in tightly closed flasks. Parts of the saturated octanol phases were centrifuged (30 minutes, 20°C,15000 rpm).

A further three flasks were prepared with about 17 g of the test item and 25 ml distilled water. The batches were stirred for different times at 30°C(experiment G for 72 h, experiment F for 48 h, experiment E for 24 h) in tightly closed flasks. After equilibration for 24 h at 20°C aliquots of the saturated aqueous phase were taken and centrifuged (30 minutes, 20°C,15000 rpm). Aliquots of the clear viscous aqueous phases were filtered through 0.2 μm membrane filters and diluted approx. 0.1 to 1 00 with the eluent at the beginning of the HPLC-measurement.

The saturation concentration of the test item in water was determined to be 396.7 g/l (without correction for the purity).

The saturation concentration of the test item in n-octanol was determined to be: <0.16 mg/L

From the individual solubilities the log Kow can be calculated to <-6.39.

 

The partition coefficient n-octanol/water of the test item at room temperature, performed according to the flask method (individual solubilities in water and n-octanol), was determined to: log Kow -6.4