2(1H)-Pyridinone, 1-(acetyloxy)-

Water solubility

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes

Type of method:

other: stability testing

Test material

Test material information

Constituent 1

Reference substance name:

2-oxo-1,2-dihydropyridin-1-yl acetate

EC Number:

689-986-7

Cas Number:

1742-79-6

Molecular formula:

C7H7NO3

IUPAC Name:

2-oxo-1,2-dihydropyridin-1-yl acetate

Constituent 2

Reference substance name:

1742-78-6

IUPAC Name:

1742-78-6

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.