Calcium 4-chloro-2-(5-hydroxy-3-methyl-1-(3-sulfonatophenyl)pyrazol-4-ylazo)-5-methylbenzenesulfonate

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

According to Directive 84/449/EEC and GLP

Qualifier:

according to guideline

Guideline:

other: Directive 84/449/EEC, annex V, C.10.

GLP compliance:

yes

Analytical monitoring:

yes

Buffers:

buffers were prepared as specified in Directive 84/449/EEC

- pH: 4
- Composition of buffer: aqueous solution of potassium biphthalate with 0.1 mol/L sodium hydroxide; adjusted to pH 4

- pH: 7
- Composition of buffer: aqueous solution of 0.05 mol/L potassium dihydrogenorthophosphate; adjusted to pH 7 with sodium hydroxide

- pH 9:
- Composition of buffer: solution of 0.05 mol/L boric acid in aqueous potassium chloride (0.05 mol/L) solution; adjusted to pH 9 with sodium hydroxide

Number of replicates:

1

Preliminary study:

Due to the low water solubilty of the test substance DMF was added to increase solubility (as specified in Directive 84/449/EEC)
A stock solution of 115 mg test substance in 100 mL DMF was prepared. 1 mL stock solution was added to a volumetric flask and filled up to 100 mL with the buffer solutions respectively.
In the preliminary test volumetric flasks were heated at 50°C for 2.4 h and 5 d. After heating the test solutions were cooled with ice and the concentrations were measured immediately.

Transformation products:

not measured

pH:

4

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Remarks on result:

hydrolytically stable based on preliminary test

Results preliminary test

Time duration	pH	Concentration start [mg/L]	Concentration end [mg/L]	Degradation [%]
2.4 h	4.0	11.4	11.3	0.7
2.4 h	7.0	11.4	11.4	0.6
2.4 h	9.0	11.4	11.3	1.2
5 d	4.0	10.4	10.4	0
5 d	7.0	10.4	10.2	1.6
5 d	9.0	10.4	9.9	4.3

Validity criteria fulfilled:

yes

Conclusions:

According to the criteria of Directive 84/449/EEC the test substance is regarded as hydrolytically stable.

Reference 2

Endpoint:

hydrolysis

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Transformation products:

not measured

pH:

4

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Remarks on result:

hydrolytically stable based on preliminary test

Description of key information

Hydrolysis

In the preliminary test degradation was below 10 % after 5 days (= t_0.5> 1 year). Therefore, the test substance is regarded as hydrolytically stable at pH 4, 7 and 9 and no additional testing is required.