Hexanamide, N-(2-hydroxyethyl)-3,5,5-trimethyl-

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 August 2012 - 17 January 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

in compliance with GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: 5, 1, 0.1 and 0 Days (staggered introduction to test so all samples analysed together)
- Sampling method: Dilution with acetonitrile
- Sampling intervals/times for pH measurements: At end of test
- Sampling intervals/times for sterility check: No sterility check, Tier 1 assessment only
- Sample storage conditions before analysis: ambient - samples vialled immediatly for analysis

Buffers:

- pH: 4
- Type and final molarity and composition of buffer: Aqueous pH 4 buffer was prepared such that the final solution contained ca 9 mM sodium hydroxide and ca 50 mM monopotassium citrate in a 1 L flask. This was filtered through a 0.45 μm nylon filter. The pH of the buffer used was 4.01. This was purged with nitrogen gas to remove dissolved oxygen.

- pH: 7
- Type and final molarity and composition of buffer: Aqueous pH 7 buffer was prepared such that the final solution contained ca 35 mM sodium hydroxide and ca 50 mM monopotassium phosphate in a 1 L flask. This was filtered through a 0.45 μm nylon filter. The pH of the buffer used was 7.00. This was purged with nitrogen gas to remove dissolved oxygen.

- pH: 9
- Type and final molarity and composition of buffer: Aqueous pH 9 buffer was prepared such that the final solution contained ca 21 mM sodium hydroxide, ca 50 mM monopotassium chloride and ca 50 mM boric acid in a 1 L flask. This was filtered through a 0.45 μm nylon filter. The pH of the buffer used was 9.01. This was purged with nitrogen gas to remove dissolved oxygen.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 15 mL amber glass vessels
- Sterilisation method: filtration of buffer
- Lighting: None
- Measures taken to avoid photolytic effects: Physical covering of hydrolysis test
- Measures to exclude oxygen: headspace purged and minimised, vessels capped.

- If no traps were used, is the test system closed/open: Closed
- Is there any indication of the test material adsorbing to the walls of the test apparatus? No
TEST MEDIUM
- Volume used/treatment: 10 mL
- Kind and purity of water: Milli_Q water, de-ionised reverse osmosis water
- Renewal of test solution: no renewal
- Identity and concentration of co-solvent: acetonitrile (0.25% v/v)
OTHER TEST CONDITIONS
- Adjustment of pH: Not required
- Dissolved oxygen: Not measured

Duration:

5 d

pH:

4.01

Initial conc. measured:

ca. 0.223 g/L

Duration:

5 d

pH:

7

Initial conc. measured:

ca. 0.21 g/L

Duration:

5 d

pH:

9.01

Initial conc. measured:

ca. 0.243 g/L

Number of replicates:

3 replicates at 4 timepoints

Positive controls:

no

Negative controls:

no

Statistical methods:

Mean % recoveries and difference in recovery from T0

Ln recovery regression

Preliminary study:

After 5 days the substance coating additives test item was shown to have hydrolysed less than 10% compared to T0 in pH 4, 7 and 9 buffer at 50 ± 0.5 °C.

This indicates that the test item was hydrolytically stable at pH 4, 7 and 9, and significant hydrolysis did not occur.

Transformation products:

no

Details on hydrolysis and appearance of transformation product(s):

- Other: Significant hydrolysis not observed, no transformation products screened for

% Recovery:

ca. 98.6

St. dev.:

2.97

pH:

4.01

Temp.:

50 °C

Duration:

ca. 5 d

% Recovery:

ca. 102.8

St. dev.:

0.32

pH:

7

Temp.:

50 °C

Duration:

ca. 5 d

% Recovery:

ca. 92.4

St. dev.:

2.52

pH:

9.01

Temp.:

50 °C

Duration:

ca. 5 d

Key result

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

Validity criteria fulfilled:

yes

Conclusions:

The hydrolysis of the substance coating additives was assessed in aqueous buffers at pH 4, 7 and 9 at 50 ± 0.5 °C. After 5 days at each pH, the substance coating additives were shown to have hydrolysed less than 10% compared to T0. This indicates that the substance coating additives was hydrolytically stable and significant hydrolysis did not occur at environmentally relevant pH values.

Executive summary:

A study was conducted to determine the hydrolysis potential of the test substance according to OECD TG 111, in compliance with GLP. The hydrolysis of the test substance was assessed in aqueous buffers at pH 4, 7 and 9 at 50 ± 0.5 °C. After 5 days at each pH, the test substance was shown to have hydrolysed less than 10% compared to T0. Under the study conditions, since significant hydrolysis did not occur at environmentally relevant pH values and the test substance was considered to be hydrolytically stable (Browne, 2013).

Description of key information

The test substance was found to be hydrolytically stable at environmentally relevant pH values.

Additional information

A study was conducted to determine the hydrolysis potential of the test substance according to OECD TG 111, in compliance with GLP. The hydrolysis of the test substance was assessed in aqueous buffers at pH 4, 7 and 9 at 50 ± 0.5 °C. After 5 days at each pH, the test substance was shown to have hydrolysed less than 10% compared to T0. Under the study conditions, since significant hydrolysis did not occur at environmentally relevant pH values and the test substance was considered to be hydrolytically stable (Browne, 2013).