SUMILIZER GP

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Data waiving:

study technically not feasible

Justification for data waiving:

the study does not need to be conducted because the substance is highly insoluble in water

other:

Reference 2

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

11 - 18 Mar 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The test solution was filtered before testing.

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

1981

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Remarks:

Federal Office of Public Haelth, Bern, Switzerland

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling method: After incubation, 50 µL aliquots were analyzedat each pH value.

Buffers:

- pH: 4
- Type and final molarity of buffer: Biphtalate buffer (Baker, Art.No. 5657)
- Composition of buffer: not provided

- pH: 7
- Type and final molarity of buffer: Phosphate buffer (Baker, Art.No. 5656)
- Composition of buffer: not provided

- pH: 9
- Type and final molarity of buffer: Borate buffer (Baker, Art.No. 7145)
- Composition of buffer: not provided

Details on test conditions:

TEST SYSTEM
- Material of test flasks, other equipment used: glass
- Sterilisation method: The buffer solutions were sterilized for 25 minutes in an autoclave prior to first use.
- Measures to exclude oxygen: Nitrogen was passed through the buffer solutions for 3 minutes except when freshly sterilized.

TEST MEDIUM
- Volume used/treatment: 100 mL
- Preparation of test medium: 21.75 mg (pH 4), 18.13 mg (pH 7) or 21.71 mg (pH 9) of the test item were dissolved in 2 mL acetonitrile with aid of sonication. The solution was made up to 100 ml with the respective buffer solution, ultrasonified for another 3 minutes and submitted to a 0.45 µm filtration. To obtain a test solution of not more than half the water solubility, the solution was diluted 1:1 with the respective buffer.

Positive controls:

no

Negative controls:

no

Preliminary study:

The solubility of the test item in the buffer solutions pH 4.0, pH 7.0 and pH 9.0 was very low. It was not possible to increase the solubility of the test item with the use of acetonitrile as solubilizer. No test item peak could be detected in the test item sample chromatogram.

Transformation products:

not measured

% Recovery:

0

pH:

4

Temp.:

50 °C

% Recovery:

0

pH:

7

Temp.:

50 °C

% Recovery:

0

pH:

9

Temp.:

50 °C

Details on results:

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.

Validity criteria fulfilled:

not applicable

Conclusions:

The presented method according to OECD 111 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 at pH 4.0, pH 7.0 and pH 9.0.

Additional information

The substance has an extremely low water solubility. This indicates that it is difficult to determine the hydrolytic half-life experimentally. According to REACH Annex VIII Column 2, a study on the hydrolysis of a substance does not need to be conducted, if the substance is highly insoluble in water.

This is supported by a study performed according to OECD 111 determining the hydrolysis behaviour of the test item in water at pH 4, pH 7 and pH 9. Acetonitrile (2%) was used as a solvent to increase the solubility of the test item in the test solutions. However, the solubility of the test item was very low and no test item could be detected analytically.