3-((3,4-dicyanophenyl)sulfonyl)-N-(2-hydroxypropyl)propane-1-sulfonamide

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental starting date: 03 October 2017. Experimental completion date: 25 March 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

yes

Remarks:

The study plan did not have sufficient information on the test substance item for identification purposes and further test item information was included in the report. This deviation is not considered to have had any impact on the integrity of the study.

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

The study plan did not have sufficient information on the test substance item for identification purposes and further test item information was included in the report. This deviation is not considered to have had any impact on the integrity of the study.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on test conditions:

Stock solutions of test item were prepared at a nominal concentration of 100 mg/L in the three buffer solutions; a 1% co-solvent of acetonitrile was used to aid solubility. The stock solutions were split into individual glass vessels for each data point, sealed with minimal headspace. These sample solutions were shielded from light whilst maintained at the test temperature.

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

>= 98.8 mg/L

Remarks:

Preliminary Test

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

ca. 101 mg/L

Remarks:

Preliminary Test

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

ca. 112 mg/L

Remarks:

Preliminary Test

Preliminary study:

Results from the Preliminary Test/Tier 1 showed it was necessary to undertake further testing at pH 7 and pH 9.

pH 4 at 50 °C 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 °C result: The extent of hydrolysis after 120 hours indicated that a further test (Tier 2) was required to estimate the rate constant and half-life at 25 °C.

pH 9 at 50 °C result: The extent of hydrolysis after 120 hours indicated that a further test (Tier 2) was required to estimate the rate constant and half-life at 25 °C.

Transformation products:

not measured

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Key result

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

487 000 h-1

DT50:

593 d

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

2 050 h-1

DT50:

14.1 d

Validity criteria fulfilled:

yes

Conclusions:

The test substance was hydrolytically stable at pH 4 with an estimated half-life of > 1 year at 25°C. The substance did undergo hydrolysis at pH 7 and pH 9 with an estimated half-life of 593 and 14.1 days at 25°C respectively.

Executive summary:

Introduction

The study was undertaken to asssess the hydrolysis as a function of pH. The method was designed to meet the requirments of the following guidelines:

1) C.7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008

2) Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

Method

Preliminary Test

Sample solutions at pH 4, 7 and 9 were maintained at 50.0 ± 0.5 °C for a period of 120 hours. The concentration of test item in the sample solutions was determined by high performance liquid chromatography (HPLC) with ultraviolet (UV) detection.

Results from the Preliminary Test showed it was necessary to undertake further testing at pH 7 and pH 9. The concentration of test item in the sample solutions from thos further testing was determined by liquid chromatography with mass selective detection (LC-MS).

Results

pH	Estimated Rate Constant at 25°C (hr-1)	Estimated Half-Life at 25°C
4	-	> 1 year
7	4.87 x 10^-5	593 days
9	2.05 x 10^-3	14.1 days

Conclusion

The test substance was hydrolytically stable at pH 4 with an estimated half-life of > 1 year at 25°C. The substance did undergo hydrolysis at pH 7 and pH 9 with an estimated half-life of 593 and 14.1 days at 25°C respectively.

Description of key information

Hydrolysis as a function pH for the test susbtance at pH 4, 7 nad 9.

Key value for chemical safety assessment

Half-life for hydrolysis:

14.1 d

at the temperature of:

50 °C