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Environmental fate & pathways

Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from January 23, 2007 to March 5. 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent/transformation products: 0, cca 1 day, cca 2 days, cca 4 days, cca 5 days
- Sampling method: sampling from volumetric flask by pipette and diluting with water to required concentration.
- Sampling intervals/times for pH measurements:
- Sampling intervals/times for sterility check:
- Sample storage conditions before analysis: The samples were analyzed in a short time after sampling.
- Other observation: no
- Temperature control: The actual temperature of the thermostatic bath was controlled during the whole test every when the sampling was done.
Buffers:
- pH: 4,7,9
- Type and final molarity of buffer: Buffer mixtures – Clark and Lubs
- Composition of buffer:
pH 4: phthalate buffer
pH 7: fosphate buffer
pH 9: borate buffer
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: volumetric flask 250 mL
- Sterilisation method: no
- Lighting: no (aluminium foil)
- Is there any indication of the test material adsorbing to the walls of the test apparatus? no

TEST MEDIUM
- Volume used/treatment 250 mL
- Kind and purity of water: distilled water
- Preparation of test medium:
- Renewal of test solution:

OTHER TEST CONDITIONS
- Adjustment of pH: The actual pH value of each buffer was measured. The pH-meter calibrated to buffer solutions CertiPUR was used.
- Adjustment of temperature: The actual temperature of the thermostatic bath was controlled during the whole test every when the sampling was done. The calibrated thermometer was used and a temperature correction was taken into account via information from the calibration list.
Duration:
5 d
pH:
4.1
Temp.:
50 °C
Initial conc. measured:
ca. 1 g/L
Duration:
5 d
pH:
7
Temp.:
50 °C
Initial conc. measured:
ca. 1 g/L
Duration:
5 d
pH:
8.8
Temp.:
50 °C
Initial conc. measured:
ca. 1 g/L
Number of replicates:
2
Positive controls:
no
Negative controls:
no
Preliminary study:
The preliminary test shows that less than 10 % of the test substance was hydrolysed within 5 days period at the pH 4.1, 7.0 and 8.8.
Test performance:
The half-life time of hydrolysis can therefore be expected grater than one year at 25°C and further testing was not required.
Transformation products:
no
Key result
pH:
4
Temp.:
25 °C
DT50:
> 1 yr
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): no

Results of preliminary test : pH = 4.1

Sampling

Measurement

Difference to time = 0

(%)

Time

(days)

Temperature

(°C)

No.

Absorbance

(AU)

0

50.0

I

A

1.2706

B

1.2702

II

A

1.2631

B

1.2623

Average

1.267

0

1.12

50.0

I

A

1.2316

B

1.2314

II

A

1.2335

B

1.2332

Average

1.232

-2.7

3.92

50.0

I

A

1.2442

B

1.2447

II

A

1.2394

B

1.2373

Average

1.241

-2.0

4.84

50.0

I

A

1.2525

B

1.2516

II

A

1.2583

B

1.2573

Average

1.255

-0.9

Results of preliminary test : pH = 7.0

Sampling

Measurement

Difference to time = 0

(%)

Time

(days)

Temperature

(°C)

No.

Absorbance

(AU)

0

50.0

I

A

2.3560

B

2.3574

II

A

2.3695

B

2.3703

Average

2.363

0

1.06

50.0

I

A

2.3661

B

2.3662

II

A

2.3565

B

2.3581

Average

2.362

-0.1

3.90

50.0

I

A

2.3474

B

2.3454

II

A

2.3431

B

2.3411

Average

2.344

-0.8

4.82

50.0

I

A

2.3669

B

2.3731

II

A

2.3828

B

2.3878

Average

2.378

0.6

Results of preliminary test : pH = 8.8

Sampling

Measurement

Difference to time = 0

(%)

Time

(days)

Temperature

(°C)

No.

Absorbance

(AU)

0

50.0

I

A

2.5071

B

2.5084

II

A

2.5101

B

2.5096

Average

2.509

0

1.07

50.0

I

A

2.5032

B

2.5052

II

A

2.5108

B

2.5074

Average

2.507

-0.1

3.89

50.0

I

A

2.5216

B

2.5205

II

A

2.5499

B

2.5505

Average

2.536

1.1

4.80

50.0

I

A

2.5102

B

2.5134

II

A

2.5073

B

2.5047

Average

2.509

0.0

Validity criteria fulfilled:
yes
Conclusions:
The half-life times of hydrolysis at all tested pH (4, 7 and 9) and at 25°C were estimated as higher than 1 year.
Executive summary:

The estimation is performed with respect to the results of preliminary test and with respect to the conclusion stated in the used methodology - Method C.7 – Degradation – Abiotic Degradation Hydrolysis as a Function of pH, Directive 92/69/EEC. Published in OJ No L 383A December 1992.

Description of key information

Method C.7 – Degradation – Abiotic Degradation Hydrolysis as a Function of pH, Directive 92/69/EEC. Published in OJ No L 383 A, December 1992
GLP study

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
25 °C

Additional information

Hydrolysis as a function of pH of the test substance was studied. The half-life times of hydrolysis at all tested pH (4, 7 and 9) and at 25ºC were estimated as higher than 1 year.