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Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2009-05-12 to 2009-06-17
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Batch No.: 08111121
Purity: 98%
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
- Sampling intervals: 0, 10 min
Buffers:
pH 4.0:
Potassium dihydrogen orthophosphate (3.0 g) and disodium hydrogen orthophosphate dodecahydrate (6.4 g) were dissolved in purified water (950 mL) and the pH was adjusted to 4.0 ± 0.05 with orthophosphoric acid. The volume was then adjusted to 1000 mL with purified water.

pH 7.0:
Potassium dihydrogen orthophosphate (13.6 g) was dissolved in purified water (1900 mL), 1M sodium hydroxide (60 mL) was added and the pH was confirmed to be 7.0 ± 0.05. The volume was then adjusted to 2000 mL with purified water.

pH 9.0:
Disodium tetraborate decahydrate (16.6 g) and potassium dihydrogen orthophosate (1.8 g) were dissolved in purified water (950 mL) and the pH was adjusted to 9.0 ± 0.05 with 1M hydrochloric acid. The volume was then adjusted to 1000 mL with purified water.
Duration:
10 min
pH:
4
Temp.:
10 °C
Duration:
10 min
pH:
7
Temp.:
10 °C
Duration:
10 min
pH:
9
Temp.:
10 °C
Positive controls:
no
Negative controls:
no
Preliminary study:
At each of pH 4, 7 and 9 and 10 ± 0.5ºC, greater than 50% hydrolysis had occurred after 10 minutes. At pH 9, the rate of hydrolysis was so rapid that the test substance was not detected at the initial timepoint.
Transformation products:
yes
No.:
#1
No.:
#2
No.:
#3
No.:
#4
Key result
pH:
4
Temp.:
10 °C
DT50:
< 10 min
Key result
pH:
7
Temp.:
10 °C
DT50:
< 10 min
Key result
pH:
9
Temp.:
10 °C
DT50:
< 10 min
Details on results:
pH of test solutions: The results show that there was a significant decrease in pH (from nominal test pH) in each case, consistent with rapid production of the breakdown product, hydrofluoric acid.
Conclusions:
The test substance was determined to be hydrolytically unstable under acidic, neutral and basic conditions, with a half-life of less than 10 minutes at 10ºC.
Executive summary:

A study was performed to determine the rate of hydrolysis of the test substance as a function of pH in accordance with the preliminary test according to EU Method C.7 and the OECD Guidelines for Testing of Chemicals, Method 111. As method development work had indicated extremely rapid hydrolysis, the procedure was conducted at 10ºC.

The preliminary study showed that at each of pH 4, 7 and 9 and 10 ± 0.5ºC, greater than 50% hydrolysis had occurred after 10 minutes. No further testing was necessary.

The test substance was determined to be hydrolytically unstable under acidic, neutral and basic conditions, with a half-life of less than 10 minutes at 10ºC.

Description of key information

The test substance was determined to be hydrolytically unstable under acidic, neutral and basic conditions, with a half-life of less than 10 minutes at 10ºC.

Key value for chemical safety assessment

Half-life for hydrolysis:
10 min
at the temperature of:
10 °C

Additional information

A study was performed to determine the rate of hydrolysis of the test substance as a function of pH in accordance with the preliminary test according to EU Method C.7 and the OECD Guidelines for Testing of Chemicals, Method 111. As method development work had indicated extremely rapid hydrolysis, the procedure was conducted at 10ºC.

The preliminary study showed that at each of pH 4, 7 and 9 and 10 ± 0.5ºC, greater than 50% hydrolysis had occurred after 10 minutes. No further testing was necessary.

The test substance was determined to be hydrolytically unstable under acidic, neutral and basic conditions, with a half-life of less than 10 minutes at 10ºC.