Registration Dossier

Administrative data

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26.02.2019 - 11.03.2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Version / remarks:
1995
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
GLP compliance:
no
Type of method:
flask method

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Results and discussion

Water solubility
Key result
Water solubility:
0.9 g/L
Conc. based on:
test mat. (dissolved fraction)
Incubation duration:
<= 72 h
Temp.:
20 °C
pH:
< 7

Any other information on results incl. tables

For the main test three flasks were prepared with an amount of test item and water, and one flask only with water. After stirring and centrifugation the aqueous phases were dilutedwith acetonitrileand measured by means of HPLC. The solution of each flask has been measured twice. The values represented in the table are rounded values. The calculation was carried out with the original not rounded values.

After the stirring time the test solutions showed a change in colour to brownish and black undissolved particles could be observed inside the flasks. In its delivered state, the test item is an off-white powder, which does not contain any black particles. The change in colour and the formation of black particles may be caused by a reaction of the test item with water. Due to these observations, the following values have to be used with caution and a possible reaction of the test item with water should be further investigated.

Results of the flask method

Flask

1a (72 h)

2a (48 h)

3a (24 h)

4a (72 h)

measured value [mg/L]

42.10 / 42.77

41.48 / 41.57

45.19 / 45.82

0 / 0

aliquot of the flask [mL]

0.05

0.05

0.05

0.05

total volume after dilution [mL]

1

1

1

1

water solubility [g/L]

0.84 / 0.86

0.83 / 0.83

0.90 / 092

0 / 0

average water solubility [g/L]

0.85

0.83

0.91

0

mean value of the water solubility [g/L]

0.86

0

standard deviation [g/L]

0.04

--

relative standard deviation [%]

4.8

--

To verify the accuracy of the analytical method freshly prepared standard solutions (prepared with the test item) were measured in between the samples of the flask method.

Measurements of standard solutions

Standard solution

(nominal value [mg/L])

Measured value [mg/L]

Repeatability [%]

Ü1 (51.5)

50.97

99.0

50.90

98.8

Ü2 (61.9)

61.93

100.1

62.46

100.9

The recovery rate of the measured standard solutions was in the range from 98.8 % to 100.9%, which shows a good accuracy of the analytical method.

Applicant's summary and conclusion

Conclusions:
The water-solubility of trimethylhydroquinone was determined to be 0.9 g/L according to the flask method.
Executive summary:

According to OECD Test Guideline 105 (1995) and Regulation EC No. 440/2008 Method A.6. the water solubility at 20°C of the test item 2,3,5-Trimethylhydroquinonewas determined to be:

cS = 0.9 g/L

RSD = 4.8 %

Due to the fact that the solution of the test item changed its colour to brownish and black particles could be observed inside the flasks after the stirring time, a reaction with water cannot be excluded and the stated value has to be used with caution. These observations should be further investigated.