Aluminum, benzoate C16-18 fatty acids complexes - high aluminium

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20/7/17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

(benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium

EC Number:

259-105-7

EC Name:

(benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium

Cas Number:

54326-11-3

Molecular formula:

C25H41AlO5

IUPAC Name:

aluminum hydroxide benzoate stearate

Constituent 2

Reference substance name:

aluminum hydroxide benzoate palmitate

Molecular formula:

C23H37AlO5

IUPAC Name:

aluminum hydroxide benzoate palmitate

Constituent 3

Reference substance name:

Aluminium benzoate salts of other fatty acids

IUPAC Name:

Aluminium benzoate salts of other fatty acids

Constituent 4

Reference substance name:

Aluminium fatty acid salts

Cas Number:

Not available.

Molecular formula:

Not available.

IUPAC Name:

Aluminium fatty acid salts

Test material form:

solid: particulate/powder

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Buffers:

pH 4 (0.05 M) Citrate Buffer
23 g of potassium dihydrogen citrate were dissolved in 1 L of water.
An aliquot of 0.50 L was mixed with 0.09 L of 0.1 M NaOH and filled up with water to 1 L to
give a pH of 4.
pH 7 (0.05 M) Phosphate Buffer
13.6 g of potassium dihydrogen phosphate were dissolved in 1 L of water.
An aliquot of 0.50 L was mixed with 0.296 L of 0.1 M NaOH and filled up with water to 1 L
to give a pH of 7.
EAG Laboratories ID P 4218 G Page 12
pH 9 (0.05 M) Borate Buffer
19 g of sodium tetraborate decahydrate were dissolved in 1 L of water.
An aliquot of 0.85 L was mixed with 0.15 L of 0.1 M HCl (prepared from 10 M HCl, Merck,
32 %) to give a pH of 9.

Number of replicates:

Two replicate test solutions were prepared for water and each buffer solution.

Results and discussion

Transformation products:

yes

Identity of transformation products

No.:

#1

Reference

Reference substance name:

Unnamed

IUPAC name:

benzoic acid

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 200-618-2]

CAS number:

65-85-0

Identity:

Benzoic acid

Identifier:

IUPAC name

Identity:

Benzoic acid

Molecular formula:

C7H6O2

Molecular weight:

122.121

SMILES notation:

OC(=O)c1ccccc1

InChl:

InChI=1/C7H6O2/c8-7(9)6-4-2-1-3-5-6/h1-5H,(H,8,9)

Details on hydrolysis and appearance of transformation product(s):

Hydrolysis was examined in demineralized water and in aqueous buffer solutions at pH 4, 7 and 9. Aliquots of the hydrolysis systems were collected at several time points and analysed immediately by LC-MS/MS to follow the formation of the expected hydrolysis product benzoic acid. Analysis of the intact test item complex was considered not possible.
Within the first couple of minutes about half and more of the amount of test item dosed was already hydrolysed to form free benzoic acid. This phase was noted as a 1st phase of an
obviously bi-phasic kinetic, whereby the 1st phase half-life of the test item was estimated to be
less than 6 to 7 minutes for demineralised water and the pH 4 buffer, for the pH 7 and pH 9
buffer the 1st phase half-life was estimated to be shorter than 2 minutes.
The slower, 2nd phase half-life times were obtained by applying 1st order kinetics and range from about 0.4 hours in pH 9 buffer, 0.9 hours in demineralized water, 1.5 hours for pH 4 buffer, and 1.8 hours in pH 7 buffer (always mean of two separate hydrolysis samples).

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

Key result

pH:

4

Temp.:

20 °C

Hydrolysis rate constant:

0.008 min-1

DT50:

1.5 h

Dissipation DT50 of parent compound 2

Key result

pH:

7

Temp.:

20 °C

Hydrolysis rate constant:

0.011 min-1

DT50:

1.8 h

Dissipation DT50 of parent compound 3

Key result

pH:

9

Temp.:

20 °C

Hydrolysis rate constant:

0.032 min-1

DT50:

0.4 h

Details on results:

Within the first couple of minutes about half and more of the amount of test item dosed was already hydrolysed to form free benzoic acid. This phase was noted as a 1st phase of an obviously bi-phasic kinetic, whereby the 1st phase half-life of the test item was estimated to be
less than 6 to 7 minutes for demineralised water and the pH 4 buffer, for the pH 7 and pH 9
buffer the 1st phase half-life was estimated to be shorter than 2 minutes.
The following table summarizes the half-lives of the slower, 2nd phase. These half-life times
were obtained by applying 1st order kinetics and range from about 0.4 hours in pH 9 buffer,
0.9 hours in demineralized water, 1.5 hours for pH 4 buffer, and 1.8 hours in pH 7 buffer
(always mean of two separate hydrolysis samples).

Applicant's summary and conclusion

Conclusions:

Within the first couple of minutes about half and more of the amount of test item dosed was
already hydrolysed to form free benzoic acid. This phase was noted as a 1st phase of an obviously bi-phasic kinetic, whereby the 1st phase half-life of the test item was estimated to be
less than 6 to 7 minutes for demineralised water and the pH 4 buffer, for the pH 7 and pH 9
buffer the 1st phase half-life was estimated to be shorter than 2 minutes.
The slower, 2nd phase half-life times ranged from about 0.4 hours in pH 9 buffer, 0.9 hours in demineralized water, 1.5 hours for pH 4 buffer, and 1.8 hours in pH 7 buffer.