Reactive Orange 143

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 December 2011 to 09 March 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(2008)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

(2004)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.2120 (Hydrolysis of Parent and Degradates as a Function of pH at 25°C)

Version / remarks:

(2008)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Analytical purity: 46.2 % (4 main constituents)
- Lot/batch No.: TZ 5719 / BOP 02-11
- Expiration date of the lot/batch: 01 April 2016

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

Acetate buffer pH 4, 0.1 M: solution of 16.7% (v/v) 0.1 M sodium acetate and 83.3% (v/v) 0.1 M acetic acid. The buffer contains 0.0009% (w/v) sodium azide.

Phosphate buffer pH 7, 0.1 M: solution of 0.1 M potassium dihydrogenphosphate adjusted to pH 7 using 10 N sodium hydroxide. The buffer contains 0.0009 % (w/v) sodium azide.

Borate buffer pH 9, 0.1 M: solution of 0.1 M boric acid and 0.1 M potassium chloride adjusted to pH 9 using 10 N sodium hydroxide. The buffer contains 0.0009 % (w/v) sodium azide.

Details on test conditions:

Test substance solutions were prepared in the buffer solutions at a target concentration of 137 - 192 mg/l. Each solution was filter-sterilised through a 0.2 µm FP 30/0.2 CA-S filter (Whatman, Germany) and transferred into a sterile vessel. To exclude oxygen, nitrogen gas was purged through the solution for 5 minutes. For each sampling time, duplicate sterile vessels under vacuum were filled with 6 ml test solution and placed in the dark in a temperature controlled environment at 50.1 °C ± 0.1 °C. Blank buffer solutions were treated similarly as the test samples and analysed at t=0. The pH of each of the test solutions (except for the blanks) was determined at each sampling time.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

147 - 152 mg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

201 - 204 mg/L

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

214 - 222 mg/L

Number of replicates:

For each sampling time, duplicate sterile vessels under vacuum were filled with test solution.

Positive controls:

no

Negative controls:

yes

Remarks:

No test substance was detected in the blank buffer solutions.

Preliminary study:

At pH 4, <10 % of hydrolysis was observed after 5 day (half-life time at 25 °C is >1 year). No additional testing is required.

At pH 7 and pH 9, >10 % of hydrolysis was observed after 5 days (half-life time at 25 °C is <1 year). The higher Tier test was not performed as it was concluded that for this multi-constituent it is not possible to determine the half-life time more accurate (degradation products are a part of the original test substance). Also, according to the guidelines, the purity of the test substance should be at least 95 % which is not the case for the multi-constituent FAT 40854/A.

Test performance:

Recovery is the mean concentration analysed at t=0 relative tothe nominal concentration.

Transformation products:

not specified

% Recovery:

109

pH:

4

Temp.:

50 °C

Duration:

0 h

Remarks on result:

other: St. dev. not specified

% Recovery:

112

pH:

7

Temp.:

50 °C

Duration:

0 h

Remarks on result:

other: St. dev. not specified

% Recovery:

114

pH:

9

Temp.:

50 °C

Duration:

0 h

Remarks on result:

other: St. dev. not specified

Remarks on result:

not measured/tested

Table     Hydrolysis of the test substance at pH 4, pH 7 and pH 9 at 50.0 +/1 °C

pH code	Sampling time	Analysed concentration [mg/l]	Degree of hydrolysis [%]		Actual pH
			Individual	Mean
pH 4	0 hours	147			4.0
		152			4.0
	5 days	139	6.8	6.0	4.0
		141	5.2		4.0
pH 7	0 hours	201			7.0
		204			7.0
	5 days	163	19	19	7.0
		164	19		7.0
pH 9	0 hours	222			9.0
		214			9.0
	5 days	43.4	80	80	9.0
		42.4	81		9.0

 

 

Validity criteria fulfilled:

yes

Conclusions:

At pH 4 (50 °C), 6 % of hydrolysis was observed after 5 days. As this is less than 10 %, the half-life time at 25°C is >1 year. Therefore, FAT 40584/A can be considered hydrolytically stable at pH 4, according to the OECD111 guideline. At pH 7 and pH 9 (50 °C) 19 % and 80 % of hydrolysis was observed after 5 days, respectively.

Executive summary:

In a GLP-compliant study, a hydrolysis study with FAT 40854/A was carried out according to EU method C.7 and OECD 111. At pH 4 (50 °C), 6 % of hydrolysis was observed after 5 days. As this is less than 10 %, the half-life time at 25 °C is >1 year. Therefore, FAT 40584/A can be considered hydrolytically stable at pH 4 and no additional testing is required. At pH 7 and pH 9 (50 °C), 19 % and 80 % of hydrolysis was observed after 5 days, respectively. As this value is ≥10 %, the half-life time at 25 °C is <1 year. Therefore, FAT 40584/A is considered to be hydrolytically unstable at pH 7 and 9. Nevertheless, the higher Tier test was not performed as it was concluded that for this multi-constituent it is not possible to determine the half-life time more accurate (degradation products are a part of the original test substance). Also, according to the guidelines, the purity of the test substance should be at least 95 % which is not the case for the multi-constituent FAT 40854/A.

Description of key information

At pH 4 (50 °C), 6 % of hydrolysis was observed after 5 days. As this is less than 10 %, the half-life time at 25°C is > 1 year. Therefore, FAT 40854/A TE can be considered hydrolytically stable at pH 4, according to the OECD111 guideline.
At pH 7 and pH 9 (50 °C) 19 % and 80 % of hydrolysis was observed after 5 days, respectively.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

In a GLP-compliant study, a hydrolysis study with FAT 40854/A was carried out according to EU method C.7 and OECD 111. At pH 4 (50 °C), 6 % of hydrolysis was observed after 5 days. As this is less than 10 %, the half-life time at 25 °C is >1 year. Therefore, FAT 40584/A can be considered hydrolytically stable at pH 4 and no additional testing is required. At pH 7 and pH 9 (50 °C) 19 % and 80 % of hydrolysis was observed after 5 days. As this rate is ≥10 %, the half-life time at 25 °C is <1 year. Therefore, FAT 40584/A is considered to be hydrolytically unstable at pH 7 and 9. Nevertheless, the higher Tier test was not performed as it was concluded that for this multi-constituent it is not possible to determine the half-life time more accurate (degradation products are a part of the original test substance). Also, according to the guidelines, the purity of the test substance should be at least 95 % which is not the case for the multi-constituent FAT 40854/A.