Registration Dossier

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Testing phase 2005-09-01 to 2005-10-13. Final report completed and signed 2005-11-30
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Meets the criteria for classification as Reliable without restriction according to Klimisch et al (1997)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: 92/69/EEC, C7
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
Aliquots of the sample solutions were taken from the flasks at various times and the pH of each solution recorded. The concentration of the sample solution was determined by HPLC
Buffers:
- pH: 4
- Composition of buffer: 0.01 mol dm3 Potassium hydrogen phthalate

- pH: 7
- Composition of buffer: 0.006 mol dm3 Disodium hydrogen orthophosphate (anhydrous), 0.004 mol dm3 Potassium dihydrogen orthophosphate, 0.004 mol dm3 Sodium chloride

- pH: 9
- Composition of buffer: 0.002 mol dm3 Disodium tetraborate, 0.004 mol dm3 Sodium chloride.

All buffer solutions were filtered through a 0.2 um membrane filter to ensure they were sterile. The solutions were subjected to ultrasonication and degassing with nitrogen to minimise dissolved oxygen content.
Details on test conditions:
Sample solutions were prepared in stoppered glass flasks at a nominal concentration of 1 g/l in the three buffer solutions. The solutions were shielded from light whilst maintained at the test temperature. Sample solutions at pH 4, 7 and 9 were maintained at 50.0 +/- 0.5 C for a period of 5 days. Aliquots of the sample solutions were taken from the flasks at various times and the pH of each solution recorded. The concentration of the sample solution was determined by HPLC.
Duration of testopen allclose all
Duration:
5 d
pH:
4
Temp.:
50 °C
Initial conc. measured:
0.846 g/L
Duration:
5 d
pH:
7
Temp.:
50 °C
Initial conc. measured:
0.848 g/L
Duration:
5 d
pH:
9
Temp.:
50 °C
Initial conc. measured:
0.861 g/L
Number of replicates:
2
Positive controls:
no
Negative controls:
no

Results and discussion

Transformation products:
not measured
Total recovery of test substance (in %)open allclose all
% Recovery:
101
pH:
4
Temp.:
50 °C
Duration:
2.4 h
% Recovery:
98.1
pH:
4
Temp.:
50 °C
Duration:
120 h
% Recovery:
100
pH:
7
Temp.:
50 °C
Duration:
2.4 h
% Recovery:
98.6
pH:
7
Temp.:
50 °C
Duration:
120 h
% Recovery:
101
pH:
9
Temp.:
50 °C
Duration:
2.4 h
% Recovery:
98.3
pH:
9
Temp.:
50 °C
Duration:
120 h
Dissipation half-life of parent compoundopen allclose all
pH:
4
Temp.:
25 °C
Half-life:
> 1 yr
pH:
7
Temp.:
25 °C
Half-life:
> 1 yr
pH:
9
Temp.:
25 °C
Half-life:
> 1 yr

Any other information on results incl. tables

At each of pH = 4, 7 and 9, less than 10% hydrolysis occurred after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Less than 10% hydrolysis occurred after 5 days at 50 C at pH 4, 7 and 9. Therefore, the estimated half life at 25 C was >1 year at pH 4, 7 and 9.
Executive summary:

Introduction

This study was undertaken to assess hydrolysis as a function of pH. This was carried out using Method C7 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

Results & Conclusions

At pH 4, 7 and 9 less than 10% hydrolysis was detected after 5 days at 50 C. This is equivalent to a half life greater than 1 year at 25 C.