Sodium 1-amino-9,10-dihydro-4-[5-[(2-hydroxyethyl)sulphamoyl]-3,4-xylidino]-9,10-dioxoanthracene-2-sulphonate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014

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:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: FAT 20033/L
Batch number: AT-PD13-359A1
EAS Test item code: 2014-000179
Appearance / colour: solid / dark blue
CAS number: 25797-81-3
Molecular weight 544.58 g/mol (base) 567.57 g/mol (salt)
Date of analysis: 07 Jan 2014
Expiry date: 07 Jan 2019
Storage conditions: ambient (+5 to +30 °C), dark, dry

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

The test item solutions were prepared by adding 1 mL of a 1000 mg/L stock solution in water/acetonitrile 10/15 (v/v) into an 100 mL volumetric flask and accurately filled up with the buffer solutions. Under argon atmosphere 2.0 mL of the test item solutions were given into several amber glass vials. The vials were closed with Teflon sealed screw caps. At the sampling time the samples were diluted with 2.0 mL acidified acetonitrile (acetonitrile with 1 % phosphoric acid). The concentration did not exceed 0.01 M or the half saturation concentration. The determined effective concentrations prior to storage at 50 °C were 9.49 mg/L at pH 4, 9.51 mg/L at pH 7, and 9.53 mg/L at pH 9.

Buffers:

The test was carried out at three different pH values: 4.0, 7.0 and 9.0. For this purpose, buffer solutions were prepared using reagent grade chemicals and deionized water. Applicable buffer systems are described in the Appendix of EC method C.7 (92/69/EC), OECD guideline 111. The citrate buffer pH 4.0, the phosphate buffer pH 7.0 and the borate buffer pH 9.0 were prepared in a concentration of 0.05 M on the basis of the undissociated acids. The pH value of the buffer solutions used during the test were determined with a calibrated pH meter at the selected temperature with a precision of 0.1 pH units.

Details on test conditions:

The test was carried out using a thermostatically controlled water bath at ±0.5 °C of the chosen temperature. The temperature was kept and measured to within ±0.1 °C. Photolytic interference was avoided. All suitable precautions were taken to exclude dissolved oxygen (bubbling the buffer with argon for five minutes before preparing the test solution).

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

9.49 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

9.51 mg/L

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

9.53 mg/L

Number of replicates:

4 at each pH-value

Preliminary study:

A preliminary test was performed at 50 ± 0.5 °C at three pH values: 4.0, 7.0 and 9.0. A sufficient number of measurements were made, in order to be able to estimate whether for each pH value and at 50 °C, the half-life time (t1/2) is less than 10 % of hydrolysis after 120 hours. These values correspond to a half-life time higher than one year under conditions more representative of those of the environment (25 °C).

Transformation products:

not measured

% Recovery:

103.1

pH:

4

Temp.:

50 °C

Duration:

120 h

% Recovery:

103.3

pH:

7

Temp.:

50 °C

Duration:

120 h

% Recovery:

102.7

pH:

9

Temp.:

50 °C

Duration:

120 h

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Type:

(pseudo-)first order (= half-life)

Details on results:

No significant changes of the content in the samples were observed. At pH 4, 7 and 9 less than 10 % of the test item were hydrolysed within 120 hours at 50 °C.

Table1: Time course of FAT 20033/L concentration at pH 4 at 50 °C

Time	Determined content of FAT 20033/L in sample		Actual concentration
[h]	[mg/L]		in % of initial conc.
0	9.49	100.0
120	9.78	103.1

 

Table2: Time course of FAT 20033/L concentration at pH 7 at 50 °C

Time	Determined content of FAT 20033/L in sample		Actual concentration
[h]	[mg/L]		in % of initial conc.
0	9.51	100.0
120	9.82	103.3

 

Table3: Time course of FAT 20033/L concentration at pH 9 at 50 °C

Time	Determined content of FAT 20033/L in Sample		Actual concentration
[h]	[mg/L]		in % of initial conc.
0	9.53	100.0
120	9.79	102.7

Validity criteria fulfilled:

yes

Conclusions:

The half life of FAT 20033/L at pH 4, 7 and 9 at 25 °C can be estimated to be longer than one year.

Executive summary:

FAT 20033/L was tested for hydrolysis as a function of pH according to OECD TG 111. It was shown that the hydrolysis of FAT 20033/L is negligible within the pH range relevant for natural environments (pH 4, 7 and 9), hence the half life times at pH 4, 7 and 9 are expected to be above one year at 25 °C in each case. Because the test item is stable to hydrolysis no further hydrolysis tests are necessary.

Description of key information

The half-life of FAT 20033/L at pH 4, 7 and 9 at the temperature of 25 °C was estimated to be longer than one year.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

FAT 20033/L was tested for hydrolysis as a function of pH according to OECD TG 111. It was shown that the hydrolysis of FAT 20033/L is negligible within the pH range relevant for natural environments (pH 4, 7 and 9), hence the half life times at pH 4, 7 and 9 are expected to be above one year at 25 °C in each case. Because the test item is stable to hydrolysis no further hydrolysis tests are necessary.