Registration Dossier

Administrative data

Endpoint:
hydrolysis
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
2005-01-19 - 2005-02-28
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The test had been performed according to relevant guidelines and compliant to GLP. The results are plausible and documented well.

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
GLP compliance:
yes (incl. certificate)
Remarks:
2003, Swiss Ordinance relating to Good Laboratory Practice (RS 813.016.5) based on OECD-GLP 1997 [C(97)186/Final]

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not applicable
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
After preparation of solutions of the test item with the aid of different solvents (acetonitrile, dimethylformamide, methanol and THF) and subsequent dilution with buffer solutions, aliquots of these buffered solutions were submitted to derivatisation and HPLC-analysis.
As for all tested dissolution approaches no test item was detectable with the applied method, any further continuation with the study was obsolete and no futher sampling occured.
Buffers:
Buffer pH 4, Biphthalate Baker Art. Na 5657
Buffer pH 7, Phosphate Baker Art. No. 5656
Buffer pH 9, Borate Baker Art. No. 7145
Details on test conditions:
The test item was dissolved in an aqueous solutions containing about 1 % solubilizer at a specific pH-value. The concentration of the test item was determined after derivatisation.

The solubility of the test item in the buffer solutions pH 4.0, pH 7.0 and pH 9.0 is very low, therefore a test with different solubilizers was performed to increase the solubility of the test item.
Aliquots of each test solutions were lyophilised, derivatised with BOC solution and measured using the analytical method as described under "Details on analytical methods".

Preparation of the Test Solutions with Acetonitrile as Solubilizer
pH 4.0:
A 10.33 mg sample of the test item was dissolved in 2 mL of ACN with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 4.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under "Details on analytical methods".
pH 7.0:
A 7.44 mg sample of the test item was dissolved in 2 mL of ACN with aid of sonificafion. This mixture was made up to 100 mL with buffer solution (pH 7.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.
pH 9.0:
A 8.01 mg sample of the test item was dissolved in 2 mL of ACN with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 9.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.

Preparation of the Test Solutions with DMF as Solubilizer
pH 4.0:
A 8.34 mg sample of the test item was dissolved in 2 mL of DMF with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 4.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.
pH 7.0:
A 9.59 mg sample of the test item was dissolved in 2 mL of DMF with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 7.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.
pH 9.0:
A 10.16 mg sample of the test item was dissolved in 2 mL of DMF with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 9.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.

Preparation of the Test Solutions with Methanol as Solubilizer
pH 4.0:
A 13.24 mg sample of the test item was dissolved in 2 mL of methanol with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 4.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.
pH 7.0:
A 12.43 mg sample of the test item was dissolved in 2 mL of methanol with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 7.0) and submitted to a 0.2 prn filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.
pH 9.0:
A 7.70 mg sample of the test item was dissolved in 2 mL of methanol with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 9.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.

Preparation of the Test Solutions with THF as Solubilizer
pH 4.0:
A 10.87 mg sample of the test item was dissolved in 2 mL of THF with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 4.0) and submitted to a 0.2 µm Filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.
pH 7.0:
A 8.17 mg sample of the test item was dissolved in 2 mL of THF with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 7.0) and submitted to a 0.2 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.
pH 9.0:
A 9.36 mg sample ofthe test item was dissolved in 2 mL of THF with aid of sonification. This mixture was made up to 100 mL with buffer solution (pH 9.0) and submitted to a 0.2 µm flitration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:2 with the respective buffer. An aliquot of this test solution was subjected to the derivatisation procedure as described under ¿Details on analytical methods¿.

Duration of test
Initial conc. measured:
ca. 0 other: test item not detectable due to very poor solubility in water and poor solubility in solvents
Number of replicates:
4 replicates for each pH-value, differing in the initialy used co-solvent for dissulution of the test item.
Positive controls:
no
Remarks:
not applicable as test could not be accomplished due to very poor solubility of test item
Negative controls:
no
Remarks:
not applicable as test could not be accomplished due to very poor solubility of test item
Statistical methods:
Not applicable as test could not be accomplished due to very poor solubility of test item.

Results and discussion

Preliminary study:
Not applicable
Test performance:
The test could not be accomplished. Due to very poor solubility of test item and in spite of 4 different co-solvents used for dissolution of the test item, the test item was not detectable in the different buffered solutions (pH 4, 7, and 9).
Transformation products:
not specified
Details on hydrolysis and appearance of transformation product(s):
Not applicable
Total recovery of test substance (in %)open allclose all
% Recovery:
0
pH:
4
Temp.:
20 °C
Duration:
ca. 0 h
% Recovery:
0
pH:
7
Temp.:
20 °C
Duration:
ca. 0 h
% Recovery:
0
pH:
9
Temp.:
20 °C
Duration:
ca. 0 h
Dissipation DT50 of parent compound
Remarks on result:
not determinable because of methodological limitations
Other kinetic parameters:
not applicable
Details on results:
The intended hydrolysis determination of the test item at different pH values was based an the OECD Guideline No. 111, "Hydrolysis as a Function of pH"; adopted May 12, 1981 and an the EEC Directive 92/69, Section C.7, "Abiotic Degradation: Hydrolysis as a Function of pH", L383 A, December 1992.
The solubility of the test item in the buffer solutions pH 4.0, pH 7.0 and pH 9.0 was very low. lt was not possible to increase the solubility of the test item with the use of different solubilizers (Acetonitrile, dimethyl formamide, methanol and tetrahydrofurane). Peaks obtained, if any, were too small to allow quantification or even to follow a degradation curve.
According to the EEC Directive 92/69, Section C.7, the method is applicable only to water soluble substances. The test item shows no significant solubility in the different solvent systems. Therefore, no further testing could be performed with the test item at pH 4.0, pH 7.0 and pH 9.0.
The calibration curve of the test item shows a r2 fit of 0.9994 (optimum = 1.0000). This reflects the linearity of the HPLC-system within the calibration range of 0.0070032 µg/mL (LOQ) to 1.7508 µg/mL of the test item.

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Remarks:
As study could not be accomplished due to very low solubility of test item in buffer solutions
Conclusions:
For the test item, the potential for hydrolytic degradation had been tested according to OECD-guideline for testing of chemicals no. 111 and E.U-method C.7 according to GLP (reliability category 1).
The test could not proceed further as to the first recovery-experiments after preparation of the buffered solutions of the test substance. In spite of trying 4 different co-solvents to increase dissolution of the test item in the buffer solutions all the resulting solutions were too dilute to be detectable by analytics based on HPLC/UV-Vis-spectroscopy after chemical dirivatisation (LOQ about 0.007 µg/mL).
Therefore, solubility of the test item in bufferd solutions is far too low to allow for testing of the potential for hydroyltic degradation.
Executive summary:

The intended hydrolysis determination of the test item at different pH values was based an the OECD Guideline No. 111, "Hydrolysis as a Function of pH"; adopted May 12, 1981 and an the EEC Directive 92/69, Section C.7, "Abiotic Degradation: Hydrolysis as a Function of pH", L383 A, December 1992.

The solubility of the test item in the buffer solutions pH 4.0, pH 7.0 and pH 9.0 was very low. lt was not possible to increase the solubility of the test item with the use of different solubilizers (Acetonitrile, dimethyl formamide, methanol and tetrahydrofurane). Peaks obtained, if any, were too small to allow quantification or even to follow a degradation curve.

According to the EEC Directive 92/69, Section C.7, the method is applicable only to water soluble substances. The test item shows no significant solubility in the different solvent systems. Therefore, no further testing could be performed with the test item at pH 4.0, pH 7.0 and pH 9.0.