Registration Dossier

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
08 January 2009 to 07 February 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Date of inspection: 19 August 2008; Date of signature: 04 March 2009

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Sponsor's identification : H-CB sodium salt
Description : blue solid
Purity : 94.8%
Lot number : MB-2
Date received : 04 December 2008
Storage conditions : room temperature in the dark

Radiolabelling:
no

Study design

Analytical monitoring:
yes
Duration of testopen allclose all
Duration:
120 h
pH:
4
Initial conc. measured:
0.955 g/L
Duration:
120 h
pH:
7
Initial conc. measured:
0.939 g/L
Duration:
120 h
pH:
7
Initial conc. measured:
0.942 g/L
Duration:
120 h
pH:
9
Initial conc. measured:
1 g/L
Duration:
120 h
pH:
9
Initial conc. measured:
1.02 g/L

Results and discussion

Transformation products:
no
Dissipation DT50 of parent compoundopen allclose all
pH:
4
Temp.:
50 °C
DT50:
> 1 yr
Remarks on result:
other: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C, therefore no further testing was required.
pH:
7
Temp.:
50 °C
DT50:
> 1 yr
Remarks on result:
other: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C, therefore no further testing was required.
pH:
9
Temp.:
50 °C
DT50:
> 1 yr
Remarks on result:
other: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C, therefore no further testing was required.

Any other information on results incl. tables

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

Table 2

Solution

MeanArea

Standard 265 mg/l

3.651 x 103

Standard 271 mg/l

3.716 x 103

Initial Sample A, pH 4

3.284 x 103

Initial Sample B, pH 4

3.260 x 103

Standard 265 mg/l

3.665 x 103

Standard 271 mg/l

3.739 x 103

Initial Sample A, pH 7

3.232 x 103

Initial Sample B, pH 7

3.242 x 103

Standard 265 mg/l

3.676 x 103

Standard 271 mg/l

3.735 x 103

Initial Sample A, pH 9

3.479 x 103

Initial Sample B, pH 9

3.504 x 103

Standard 251 mg/l

3.438 x 103

Standard 254 mg/l

3.498 x 103

120 Hour Sample A, pH 4

3.281 x 103

120 Hour Sample B, pH 4

3.284 x 103

Standard 251 mg/l

3.460 x 103

Standard 254 mg/l

3.509 x 103

120 Hour Sample A, pH 7

3.244 x 103

120 Hour Sample B, pH 7

3.253 x 103

Standard 251 mg/l

3.459 x 103

Standard 254 mg/l

3.497 x 103

120 Hour Sample A, pH 9

3.462 x 103

120 Hour Sample B, pH 9

3.498 x 103

 


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

Table 3    pH 4 at 50.0 ± 0.5ºC

Time (Hours)

Concentration (g/l)

% of mean initial concentration

A

B

A

B

0

0.956

0.949

100

99.6

120

0.955

0.955

100

100

Result:           Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C, therefore no further testing was required.

 

Table 4    pH 7 at 50.0 ± 0.5ºC

Time (Hours)

Concentration (g/l)

% of mean initial concentration

A

B

A

B

0

0.936

0.939

99.9

100

120

0.939

0.942

100

100

Result:           Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C, therefore no further testing was required.

 

Table 5    pH 9 at 50.0 ± 0.5ºC

Time (Hours)

Concentration (g/l)

% of mean initial concentration

A

B

A

B

0

1.01

1.01

99.6

100

120

1.00

1.02

99.4

100

Result:           Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C, therefore no further testing was required.

 


Validation

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 500 mg/l. This was satisfactory with a correlation coefficient of 1.000 being obtained.

 Discussion

No significant peaks were observed at the approximate retention time of the test material on analysis of any matrix blank solutions and it was considered not necessary to do a blank subtraction from the standard and sample chromatograms.

Additionally, one example for each pH of the diluted 120 hour timepoint samples and 120 hour timepoint analysis standards was further diluted by a factor of 50 with reverse osmosis water. These were scanned in 10 mm quartz cells on a Perkin-Elmer Lambda 20 from 200 nm to 900nm using reverse osmosis water as the reference. There was no significant difference between applicable standard and sample where the test material adsorbed in the visible spectrum range with respect to both wavelength and intensity. This provides extra evidence that the test material did not hydrolyse under the test conditions. Any significant hydrolysis would probably have altered the adsorption characteristics (wavelength and/or intensity) of the test material.

As the test material was determined to be hydrolytically stable under acidic conditions (t½ > 1 year at 25°C) no additional testing was performed at pH 1.2, 37.0 ± 0.5°C.

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:

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 using Method C7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008