Benzotriazole

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013

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)

Analytical monitoring:

yes

Details on sampling:

- Sampling method: 3 samples were taken for measurements at the beginning of the test and after 5 days
- Sampling intervals/times for sterility check: The buffered solutions of the test items were sterilised by filtration using sterile 0.2 filters. For each sampling time, fresh tubes were used to avoid microbial contamination and contact with oxygen.
- Sample storage conditions before analysis: The solutions were stored at 50 ± 0.5 °C.

Buffers:

The buffer solutions were prepared on the basis of the recommended compositions of the annex of the OECD method (buffer solutions 7 and 9) resp. Küster et al. (buffer solution 4). All chemicals used were of analytical grade. The pH was measured with a pH-meter with an uncertainty of 0.01 units and pH was adjusted to the nominal pH value ± 0.02 units.

Buffer-Solution, pH 4
- CH3COOH, 2-m (160 mL)
- CH3COONa, 1-m (80 mL)
- Water (ad 2000 mL)

Buffer-Solution, pH 7
- KH2PO4 (17.4171 g)
- Water (500 mL)
- NaOH, 2-m (29.8 mL)
- Water (ad 2000 mL)

Buffer-Solution, pH 9
- H3BO3 (6.1863 g)
- KCl (7.4579 g)
- Water (1000 mL)
- NaOH, 2-m (21.5 mL)
- Water (ad 2000 mL)

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: sterilised vials
- Sterilisation method: the solution of the buffered test solution was filtrated using sterilised 0.2 µm filters; all glassware was autoclaved before use.
- Measures taken to avoid photolytic effects: the tubes containing solutions were stored in an incubation chamber.
- Measures to exclude oxygen: sterilised vials were filled with the solutions and purged with oxygen-free argon. Fresh tubes were used for each for each sampling time to avoid microbial contamination and contact with oxygen.
- There was no indication of the test material adsorbing to the walls of the test.

TEST MEDIUM
- Preparation of test medium: the solution of the test item was mixed 1:1 with the appropriate buffer solution
OTHER TEST CONDITIONS
- Oxygen was excluded by purging the vials with oxygen-free argon during preparation.

Duration:

0 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

100

Number of replicates:

3

Preliminary study:

After 5 days (120 h) at 50 ± 0.5 °C the concentrations of the test item was about 100 % of the start concentrations at pH 4, 7, and 9. Thus the test item can be considered to be hydrolytically stable.

Test performance:

Due to the results of the tier 1 test no higher tier tests were conducted.

Transformation products:

no

% Recovery:

99.2

pH:

4

Temp.:

50 °C

Duration:

5 d

% Recovery:

101.1

pH:

7

Temp.:

50 °C

Duration:

5 d

% Recovery:

100

pH:

9

Temp.:

50 °C

Duration:

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
- Anomalies or problems encountered (if yes):

MAJOR TRANSFORMATION PRODUCTS
at pH4:
- no transformation products observed, recovery 100 %
at pH7:
- no transformation products observed, recovery 100 %
at pH9:
- no transformation products observed, recovery 100 %

Validity criteria fulfilled:

yes

Conclusions:

1H-Benzotriazole was not hydrolysed under test conditions (50 °C, pH 4, 7, and 9). Thus, the substance is hydrolytically stable and the default half-life is considered in the assessment.

Description of key information

Test substance was not hydrolysed in Tier 1 study according to OECD 111. Thus, in line with the guidance it is considered hydrolytically stable and a half-life of 365 d (default half-life) under environmental conditions is assumed.

Key value for chemical safety assessment

Half-life for hydrolysis:

365 d

at the temperature of:

20 °C