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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19 October 2006 to 24 November 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
flask method
Water solubility:
208.3 g/L
Temp.:
20 °C
Remarks on result:
other: pH not detailed within the report. RSD 0.7%. Result corrected for the purity of 52.5%
Water solubility:
396.7 g/L
Temp.:
20 °C
Remarks on result:
other: pH not detailed within the report. RSD 0.7%. Result not corrected for the purity of the substance.
Details on results:
The preliminary visual experiments showed that the water solubility of the test item is between 510 g/l and 610 g/l. Therefore the water solubility had to be determined by the “flask-method”.

Preliminary Visual Estimation of the Water Solubility and stirring test: Several preliminary test were performed with different amounts of the test item and different volumes of water.

 

Table 1: Appearance of the test mixtures – solubility test

Amount of the test item in g (total amount)

Total volume in ml

Appearance of mixture

6.11

20

Dissolved*1)

+ 2.05 (8.16)

Dissolved*2)

+ 1.01 (9.17

Dissolved*3)

+ 0.99 (10.16)

Dissolved*3), cS>510 g/l

+ 2.05 (12.21)

Undissolved*4), cS<610 g/l (379 g/kg)

*1): After adding the indicated amount of water, the solution was stirred for 15 minutes.

*2): After adding the indicated amount of water, the solution was stirred for 30 minutes.

*3): After adding the indicated amount of water, the solution was stirred for 20 minutes.

*4): After adding the indicated amount of water, the solution was stirred for about 15 hours. 1g of this solution was centrifuged after stirring.

 

The preliminary visual experiments showed that the water solubility of the test item is between 510 g/l and 610 g/l. Therefore the water solubility had to be determined by the “flask-method”.

 

Table 2: Appearance of the test mixtures – stirring test

Amount of the test item in g (total amount)

Amount of water in g (total amount)

Appearance of mixture

11.8

19.38

Could be stirred

+ 1.95 (13.75)

Could be stirred at room temperature (viscous)

+ 1.99 (15.77)

Could be stirred at room temperature (viscous), but not at 20°C

+ 2.0 (21.38)

Could not be stirred at 20°C

+ 1.0 (22.38)

Could not be stirred at 20°C

+ 1.0 (23.38)

Could be stirred at 20°C

The stirring test showed that about 400 g/kg test item can be used for the flask method.

 

Flask-Method

Table 3: Water solubility of the test item – experiment E to H

Experiment

E

F

G

H (blank)

Amount of test item (g)

16.9

16.8

16.9

--

Stirring time at 30°C (h)

24

48

72

72

pH at 24°C

3.9

4.0

4.0

5.8

Aliquot of the flasks (mg)

100.0

99.

102.1

153.1

Amount of eluent (g)

100.4

100.4

100.4

100.5

Measured concentration (g/l)

397.3 / 397.2

393.6 / 393.5

400.1 / 400.3

--

Mean concentration (g/l)

397.2

393.6

400.2

--

Water solubility (g/l)

399.2

397.2

393.8

--

Average experiment E to G (without correction for the purity): 396.7 g/l

Standard deviation: 2.7 g/l

Relative standard deviation: 0.7%

 

Table 4: Concentration of standards for recheck:

Standard

Measured concentration (g/l)

% Recovery (mean value)

Standard 4 (c = 480.9 mg/l)

460.0

95.6

Standard C (c = 323.2 mg/l)

321.1

320.21 / 321.5

99.4

99.3

Recoveries of the ‘Recheck sample’ ranged from 95.6% to 99.4%, indicating a good accuracy of the analytical method.

Conclusions:
The water solubility cS of the test item at a temperature of 20°C was determined as follows (with correction for the purity of 52.5 %):
Cs = 208.3 g/l
RSD = 0.7%
The water solubility cS of the test item at a temperature of 20°C was determined as follows (without correction for the purity):
CS = 396.7 g/l
RSD = 0.7%
Executive summary:

The purpose of this study was the determination of the water solubility c5of the test item according to the consolidated version of Guideline 67/548/EEC Annex V (Council Directive 92/69/EEC), PartA:Methods for the determination of physico-chemical properties, A.6. Water solubility; flask-method and OECD test guidelines, OECD 105 (1995) Water solubility. The study was performed in accordance with the Principles of Good Laboratory Practice (GLP) and reported with a valid GLP certificate.

 

Different preliminary tests were performed with different amounts of the test item and different volumes of water. The mixtures were stirred or treated with ultrasound and visually checked for any undissolved parts. Due to the high water solubility it had to be tested which amount of the test item could be stirred in a defined volume of water.

 

For the main test 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°Caliquots 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 preliminary visual experiments showed that the water solubility of the test item is between 510 g/l and 610 g/l. Therefore the water solubility had to be determined by the "flask-method".

 

The water solubility cSof the test item at a temperature of 20°C was determined as follows (with correction for the purity of 52.5 %):

Cs=208.3 g/l

RSD = 0.7%

The water solubility cSof the test item at a temperature of 20°C was determined as follows (without correction for the purity):

CS= 396.7 g/l

RSD = 0.7%

Description of key information

The water solubility cSof the test item at a temperature of 20°C with correction for the purity is 208.3 g/l, without correction for the purity, it is 396.7 g/l

Key value for chemical safety assessment

Water solubility:
396.7 g/L
at the temperature of:
20 °C

Additional information

The water solubility of the test item was determined according to methods A.6. Water solubility; flask-method and OECD test guidelines, OECD 105 (1995) Water solubility.

Different preliminary tests were performed with different amounts of the test item and different volumes of water. The mixtures were stirred or treated with ultrasound and visually checked for any undissolved parts. Due to the high water solubility it had to be tested which amount of the test item could be stirred in a defined volume of water.

For the main test 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°Caliquots 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 water solubility cSof the test item at a temperature of 20°C was determined as follows (with correction for the purity): Cs=208.3 g/l; RSD = 0.7%

The water solubility cSof the test item at a temperature of 20°C was determined as follows (without correction for the purity): CS= 396.7 g/l; RSD = 0.7%