Registration Dossier

Administrative data

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 May 2013 to 17 March 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Conducted according to current test guidelines and GLP compliant

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report Date:
2014

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:
yes
Type of method:
other: stability testing

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
Name: Oxypyrion acetate
CAS Number: 1742-78-6
Batch number: 14058400
Purity: 97.83%
Date of arrival: 22 April 2013
Expiry date: 30 November 2013
Storage conditions: Refrigerated (2 to 8°C)

Results and discussion

Water solubility
Remarks on result:
not determinable
Remarks:
the test substance was shown to be unstable at pH 4, 7 and 9
Details on results:
Analytical Procedures in Water for Water Solubility:
Previous work suggested that the test substance was unstable in aqueous solution.
Stability Test in Double-Distilled Water:
A preliminary test was carried out to show the stability of the Oxypyrion acetate in aqueous solution.

Over the 340-minute test period, the size of the chromatographic peak for the Oxypyrion acetate reduced in size and other peaks in the chromatogram increased in size.

The Oxypyrion acetate peak went from 99,36% of the total peak area of all peaks in the chromatogram to 29,44% of the total peak area, which equated to a drop of 69,9%. This drop in percent total peak area, along with the increase in area of other chromatographic peaks, suggests that the Oxypyrion acetate is unstable in aqueous solution.

The actual peak area dropped from 4369007 to 449518, which was a change of 89,7%.

Stability Test in Aqueous pH Buffer Solutions:
The REACH guidelines EC 1907/2006, Annex VII, state for water solubility that ‘study does not need to be conducted if the substance is hydrolytically unstable at pH 4, 7 and 9 (half-life less than 12 hours)’.
To further confirm that this was the situation for the Oxypyrion acetate, testing was carried out to show stability in pH 4, 7 and 9 aqueous buffer solutions.
For the pH 4 buffer, the peak area dropped from 289787 to 31221 over the 350 minute test period, which was a change of 89,2%. The peak area had dropped below 50% of the original peak area at the 75-minute analysis period.
For the pH 7 buffer, the peak area dropped from 238448 to 25493 over the 350 minute test period, which was a change of 89,3%. The peak area had dropped below 50% of the original peak area at the 140-minute analysis period.
For the pH 9 buffer, the peak area dropped from 207888 to 35375 over the 350 minute test period, which was a change of 83,0%. The peak area had dropped below 50% of the original peak area at the 230-minute analysis period.

Method validation:
As the test substance was shown to be unstable at pH 4, 7 and 9 no further work was required on the water solubility and this meant that an analytical method was not required. Therefore, no method validation was performed.

Water Solubility:
Due to the fact that the test substance was unstable in aqueous solution (half-life was less than 12 hours at pH 4, 7 and 9), it was considered that the determination of water solubility was impractical.

Any other information on results incl. tables

Stability Data in Double-Distilled Water

Test Sample

Time Prepared

Time elapsed from stock preparation (minutes)

Peak area of Oxypyrion acetate peak (µV*sec)

Proportion of total peak area of all peaks in chromatogram (%)

T0

09:20

0

4369007

99,36

T1

10:25

65

2805347

94,47

T2

11:30

130

1820119

77,43

T3

13:00

220

970282

59,28

T4

14:00

280

652692

40,74

T5

15:00

340

449518

29,44



Stability Data in pH 4 Buffer

Test Sample

Time Prepared

Time elapsed from stock preparation (minutes)

Peak area of Oxypyrion acetate peak (µV*sec)

Proportion of total peak area of all peaks in chromatogram (%)

T0

09:10

0

289787

96,82

T1

10:25

75

132847

86,41

T2

11:30

140

104560

76,28

T3

13:00

230

77032

60,05

T4

14:00

290

55433

49,63

T5

15:00

350

31221

38,75

 


Stability Data in pH 7 Buffer

Test Sample

Time Prepared

Time elapsed from stock preparation (minutes)

Peak area of Oxypyrion acetate peak (µV*sec)

Proportion of total peak area of all peaks in chromatogram (%)

T0

09:10

0

238448

96,83

T1

10:25

75

159013

85,37

T2

11:30

140

117579

77,27

T3

13:00

230

73972

58,69

T4

14:00

290

42897

46,16

T5

15:00

350

25493

34,06

 

Stability Data in pH 9 Buffer

Test Sample

Time Prepared

Time elapsed from stock preparation (minutes)

Peak area of Oxypyrion acetate peak (µV*sec)

Proportion of total peak area of all peaks in chromatogram (%)

T0

09:10

0

207888

96,23

T1

10:25

75

118020

84,85

T2

11:30

140

110157

74,96

T3

13:00

230

40276

59,21

T4

14:00

290

47229

49,28

T5

15:00

350

35375

39,41

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other:
Due to the fact that Oxypyrionacetate was unstable in aqueous solution (half-life was less than 12 hours at pH 4, 7 and 9), it was considered that the determination of water solubility was impractical.