3-(2-hydroxyethyl)-p-phenylenediammonium sulphate

Hydrolysis

Description of key information

Betoxol II degradation >10% was observed at all tested pH levels in a preliminary study so that further testing was necessary. Betoxol II was considered to be hydrolytically unstable at all tested conditions. An unknown transformation component was observed at a retention time of 1.6 min in the chromatograms. The maximum relative peak intensity found was 96% at pH 9.0 and 30 deg C calculated on a peak area basis relative to the initial peak area of Betoxol II. Identification of the component was not possible.

Key value for chemical safety assessment

Half-life for hydrolysis:

13.9 h

at the temperature of:

20 °C

Additional information

Hydrolysis as a function of pH for the test item Betoxol II was determined according to OECD guideline 111. The test was conducted with a test item concentration of 10 mg/L in buffer solutions of pH 5, 7 and 9 at temperatures of 20 and 30 deg C. Samples were taken at test start and at minimum of seven spaced points. Analyses of the test item Betoxol were performed by HPLC on a C18 column with sodium dodecyl sulphate as modifier and UV detection at 243nm. The test item Betoxol was determined to undergo hydrolysis at pH 5, 7 and 9 at 50 deg C based on the findings of a preliminary test. The rates of decline were >10% during 120h incubation under these conditions. In the definitive study (advanced testing for hydrolytically unstable substances) Betoxol II was found to undergo hydrolysis at all pH values (5, 7 and 9) and both tested temperatures (20 and 30 deg C). A major unknown transformation product was found at a retention time of 1.6 mins in the chromatograms. The maximum relative intensity of the unknown product was 96% of the applied Betoxol II concentration (calculated on peak area basis) at pH 9, 30 deg C and 7.1 hour of hydrolysis.