6-[[(4-methylphenyl)sulphonyl]amino]hexanoic acid

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

no

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

pH 4: (Citrate buffer acc. to Sörensen):
- Composition of buffer: Citric Acid, NaOH, HCl, destilled water

pH 7: (Phosphate buffer acc. to Sörensen):
- Composition of buffer: K2PO4-Solution, Na2HPO4-Solution

pH 9: (Borate buffer acc. to Sörensen):
- 85 mL of Borax solution (1.91 g Borax ad 100 mL Water) plus 0.1 N HCl and 1 N NaOH to adjust pH to 9.006

Details on test conditions:

- 1 g test item plus 10 mL solution of pH 4, 7, 9 respectively.
- pH measurement at t=0 and t=5d.
- stirring for 5 d at 50 °C.

pH 9 solution: the pH was too low after test item addition. Therefore, the amount of test item was lowered: 0.1 g plus 15 mL pH 9 buffer solution.

Duration:

5 d

Temp.:

50 °C

Number of replicates:

1

Positive controls:

no

Negative controls:

no

Transformation products:

no

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

Key result

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

Details on results:

pH 4: pH value at t0 = 3.5 - 4; at t5d = 4.016
- residue after filtration: no degradation detectable
- filtrate: ASC plus detectable, about 1 % of the total quantity of ASC plus found, total amount of all detected peaks except ASC plus in the filtrate = 0.5 % of original test substance concentration in the buffer solution pH 4

pH 7: pH value at t0 = 6-6.5; at t5d = 5.767
- residue after filtration: no degradation detectable
- filtrate: about 8.7 % ASC plus of the total quantity of original test substance found, total amount of all peaks except that of ASC plus = 0.28 % of original test substance concentration in the buffer solution pH 7.

pH 9: pH value at t0 = 9; at t5d = 8.672
- residue after filtration: no residue available, substance has fully dissolved
- filtrate: mainly ASC plus was found with no significant degredation.

stable against hydrolysis at pH 4, pH 7 and pH 9 (5d at 50 °C)

Validity criteria fulfilled:

yes

Executive summary:

ASC plus (6-[[(4-methylphenyl)sulphonyl]amino]hexanoic acid) was stable against hydrolysis at pH 4, pH 7 and pH 9 (5d at 50 °C) in a test according to OECD 111.

Description of key information

ASC plus (6-[[(4-methylphenyl)sulphonyl]amino]hexanoic acid) was stable at pH 4, pH 7 and pH 9 (5d at 50 °C) in a test according to OECD 111.