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Physical & Chemical properties

Water solubility

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Administrative data

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-12-11 to 2013-02-04
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
GLP compliance:
no
Type of method:
flask method

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid

Results and discussion

Water solubility
Water solubility:
8.8 g/L
Conc. based on:
test mat.
Temp.:
23 °C
pH:
5.6
Details on results:
see below

Any other information on results incl. tables

 Preliminary Visual Estimation of the Water Solubility

Different amounts of the test item and water were stirred at room temperature until the mixture appeared dissolved or the water solubility could be estimated to be below 10 mg/L.

Table 1: Appearance of the test mixtures

Amount of test item

in mg

Total volume

in ml

Appearance of mixture

104.7

0.1

undissolved1)

0.5

undissolved1)

1.0

undissolved1)

2.0

undissolved1)

10

undissolved (low turbidity)1)

1): After adding the indicated amount of water, the solution was treated with ultrasound for 15 minutes.

Table 2: Appearance of the test mixtures

Amount of the test item

in mg

Total volume

in ml

Appearance of mixture

12.1

100

low turbidity2)

11.2

500

low turbidity2)

4.9

500

very low turbidity2)

2): After adding the indicated amount of water, the solution was stirred at room temperature for about 1 day.

According to the preliminary visual estimation the water solubility seems to be lower than 10 mg/l. However, in the test item water mixtures with a concentration of about 10 mg/l only a low turbidity was observed. It is assumed that this low turbidity results from impurities of the test item with a lower solubility. Therefore the water solubility of the test item is assumed to be > 10 mg/l. Consequently the flask method was performed as main test.

Table 3: Water solubility of the test item – experiments A to D

Experiment

A

B

C

D (blank)

Amount of test item (g)

6.18

6.20

6.11

--

Amount of distilled water (mL)

30

30

30

30

Stirring time at 30 °C (h)

24

48

72

72

pH at 23 °C

5.4

5.6

5.7

6.5

Aliquot of the flasks (mL)

0.5

0.5

0.5

0.5

Dilution with methanol to volume (mL)

50

50

50

50

Aliquot of the diluted sample (mL)

0.1

0.1

0.1

0.1

Dilution with methanol / dist. water 90 : 10 % to volume (mL)

1

1

1

1

Dilution factor

1000

1000

1000

1000

Measured concentration (mg/L)

8.81 / 8.83

8.56 / 8.57

8.93 / 9.01

-- / --

Mean concentration (mg/L)

8.82

8.57

8.97

--

Water solubility (g/L)

8.82

8.57

8.97

--

The water solubility of the test item at 20 °C was determined to be 8.8 g/l.

Table 4: Accuracy test

Standard

Measured concentration (mg/l)

% Recovery

(mean values)

Standard C (c = 35.68 mg/L)

36.90 / 36.89

103.4

Standard E (c = 7.14 mg/L)

7.05 / 7.08

99.0

Standard G (c = 1.43 mg/L)

1.34 / 1.35

94.1

Recoveries of the ‘standard samples’ ranged from 94.1 % to 103.4 %, indicating a good accuracy of the analytical method.

Applicant's summary and conclusion

Conclusions:
soluble (1000-10000 mg/L)
In conclusion, the water solubility of the test item at 20 °C was determined to be 8.8 g/L.
Executive summary:

A study was performed according to EU method A.5 and OECD guideline 105 without GLP.

Initially a pre-test by visual estimation of the water solubility was performed which indicated a poor water solubility of < 10 mg/L because the solution was turbid at this low concentration. Considering that the turbidity might result from impurities of the test item the main test was performed.

In the main test the flask method was used in combination with HPLC and an external calibration (external standard method with the test item). The water solubility of the test item at a temperature of 20 °C was determined to be (without correction for the purity): Cs = 8.8 g/L.