Registration Dossier

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Testing was conducted between 27 March 2007 and 11 June 2007.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Sponsor's identification: C-Y9
Description : yellow powder
Lot number : MB-1
Date received : 6 March 2007
Storage conditions: room temperature in the dark, over silica gel
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
Preparation of samples
Sample solutions were prepared in stoppered glass flasks at a nominal concentration of 1 g/l in the three buffer solutions.
The test solutions were split into individual vessels for each data point.
The solutions were shielded from light whilst maintained at the test temperature.
Buffers:
Three buffer solutions were prepared at pH 4, 7 and 9.
Duration of testopen allclose all
Duration:
5 d
pH:
4
Temp.:
50 °C
Initial conc. measured:
1.01 g/L
Duration:
5 d
pH:
7
Temp.:
50 °C
Initial conc. measured:
1.01 g/L
Duration:
172 h
pH:
9
Initial conc. measured:
1.03 g/L

Results and discussion

Dissipation DT50 of parent compoundopen allclose all
pH:
4
Temp.:
25 °C
DT50:
> 1 yr
pH:
7
Temp.:
25 °C
DT50:
> 1 yr
pH:
9
Temp.:
25 °C
DT50:
> 1 yr

Any other information on results incl. tables

Results

Preliminary test

The mean peak areas relating to the standard and sample solutions are shown in the following table:

Solution

MeanArea

Standard 252 mg/l

5.895 x 103

Standard 253 mg/l

5.940 x 103

Initial Sample A, pH 4

5.934 x 103

Initial Sample B, pH 4

5.950 x 103

Standard 251 mg/l

5.892 x 103

Standard 251 mg/l

5.971 x 103

Initial Sample A, pH 7

5.962 x 103

Initial Sample B, pH 7

5.961 x 103

Standard 254 mg/l

5.908 x 103

Standard 253 mg/l

5.955 x 103

Initial Sample A, pH 9

6.042 x 103

Initial Sample B, pH 9

6.038 x 103

Standard 252 mg/l

5.944 x 103

Standard 251 mg/l

5.882 x 103

120 Hour Sample A, pH 4

5.835 x 103

120 Hour Sample B, pH 4

5.834 x 103

Standard 252 mg/l

5.971 x 103

Standard 251 mg/l

5.892 x 103

120 Hour Sample A, pH 7

5.792 x 103

120 Hour Sample B, pH 7

5.807 x 103

Standard 251 mg/l

5.926 x 103

Standard 251 mg/l

5.900 x 103

120 Hour Sample A, pH 9

5.131 x 103

120 Hour Sample B, pH 9

5.091 x 103

Standard 251 mg/l

5.678 x 103

Standard 253 mg/l

5.742 x 103

172 Hour Sample A, pH 9

5.909 x 103

172 Hour Sample B, pH 9

5.961 x 103

The test material concentrations at the given time points are shown in the following tables:

pH 4 at 50.0 ± 0.5ºC

 

Time (Hours)

0A

0B

120A

120B

Concentration (g/l)

1.01

1.01

0.992

0.992

% of initial

99.9

100.1

97.9

97.9

Result:             Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C.

pH 7 at 50.0 ± 0.5ºC

 

Time (Hours)

0A

0B

120A

120B

Concentration (g/l)

1.01

1.01

0.981

0.983

% of initial

100

100

97.3

97.5

Result:             Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C.

 pH 9 at 50.0 ± 0.5ºC

 

Time (Hours)

0A

0B

120A

120B

172A

172B

Concentration (g/l)

1.03

1.03

0.870

0.864

1.04

1.05

% of initial

100

100

84.4

83.8

101

102

Result:             Less than 10% hydrolysis after 172 hours at 50°C, equivalent to a half-life greater than 1 year at 25°C.

Validation

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 504 mg/l. This was satisfactory with a correlation coefficient of 1.000 being obtained.

Discussion

At pH 9, a further timepoint at 172 hours indicated that the test material had not hydrolysed as first assumed from the 120 hour timepoint. It is deemed that the 120 hour sample result was erroneous.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The estimated half-life at 25°C of the test material for pH 4, pH 7 and pH 9 has been shown to be > 1 year.

Executive summary:

Abiotic Degradation, Hydrolysis as a Function of pH. 

Assessment of hydrolytic stability was carried out using Method C7 of Commission Directive 92/69/EEC and Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004. The estimated half-life at 25ºC of the test material, for pH 4, pH 7 and pH 9 has been shown to be >1 year.