Propane-1,2,3-triyl 3,5,5-trimethylhexanoate

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 Aug - 30 Nov 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Objective of study:

other: hydrolysis in intestinal fluid simulant

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: EFSA Note for Guidance for Food Contact Materials Annex 1 to Chapter III MEASUREMENT OF HYDROLYSIS OF PLASTICS MONOMERS AND ADDITIVES IN DIGESTIVE FLUID SIMULANTS

Deviations:

yes

Remarks:

no hydrolysis test in saliva and gastric juice simulants, limited details in reporting

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Propane-1,2,3-triyl 3,5,5-trimethylhexanoate

EC Number:

260-257-1

EC Name:

Propane-1,2,3-triyl 3,5,5-trimethylhexanoate

Cas Number:

56554-53-1

Molecular formula:

C30H56O6

IUPAC Name:

1,3-bis[(3,5,5-trimethylhexanoyl)oxy]propan-2-yl 3,5,5-trimethylhexanoate

Radiolabelling:

no

Test animals

Species:

other: not specified; presumably pig in accordance with the test method used

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST DIGESTIVE SIMULANTS
INTESTINAL FLUID SIMULANT
- Description: intestinal fluid simulant according to “Note of Guidance for Food Contact Materials”, no further details given.

Administration / exposure

Route of administration:

other: mixing

Vehicle:

other: acetonitrile

Details on exposure:

HYDROLYSIS WITH INTESTINAL-FLUID SIMULANT:
A triplicate was performed. For the hydrolysis investigation the esters were dissolved in acetonitrile. These solutions were added to the intestinal-fluid simulant tempered to 37 °C. The concentration of acetonitrile in the reaction mixture was about 0.1%. Samples were taken after 0, 1, 2 and 4 hours.

Duration and frequency of treatment / exposure:

0, 1, 2 and 4 h

Doses / concentrations

Dose / conc.:

24.34 ppm

No. of animals per sex per dose / concentration:

triplicate determinations

Control animals:

no

Details on dosing and sampling:

DETERMINATION OF HYDROLYSIS PRODUCTS
- Principle: Following incubation, a naphthalene solution in acetone was added as an internal standard to the samples and the enzyme was precipitated by the addition of ice-cold acetone. After filtration the acetone was evaporated. The aqueous solutions were acidified with 0.1 M hydrochloric acid (pH 1.2) and were extracted three times with dichloromethane. After addition of an alkane standard (tridecane) and derivatization with N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) at 60°C for one hour the concentrated dichloromethane solutions were analysed by gas chromatography coupled with a mass spectrometer (GC/MS). Quantification of the esters and the hydrolysis products was performed specifically by external calibration curves.
- Recovery assays: A duplicate of three different concentrations of the acid (hydrolysis product) were performed. For the recovery investigations the acid was dissolved in acetonitrile. These solutions were added to the intestinal-fluid simulant tempered to 37°C. After 4 hours a naphthalene solution in acetone was added as an internal standard to the samples and the enzyme was precipitated by the addition of ice-cold acetone. Work-up and quantification was performed as described above.
Recovery of the ester was determined using a hydrolysis sample analogue to the "0 hour" assay.

Statistics:

Mean values of triplicate determinations were calculated.

Results and discussion

Main ADME results

Type:

other: ester hydrolysis in intestinal fluid simulant

Results:

19, 23.3 and 29.2% after 1, 2 and 4 h, respectively.

Toxicokinetic / pharmacokinetic studies

Details on absorption:

Not applicable

Details on distribution in tissues:

Not applicable

Details on excretion:

Not applicable

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

The following esters of glycerol were quantitatively determined (in ppm) after 0, 1, 2 and 4 h hydrolysis in intestinal fluid simulant, respectively:
Diester with 3,5,5-trimethylhexanoic acid (sum of two stereoisomers): 0.96, 1.07, 1.10 and 1.13 ppm
Triester with 3,5,5-trimethylhexanoic acid (parent substance): 24.34, 19.72, 18.67 and 17.22 ppm
(No monoester was detected)

The following free fatty acid was quantitatively determined (in ppm) after 0, 1, 2 and 4 h hydrolysis in intestinal fluid simulant, respectively:
3,5,5-trimethylhexanoic acid: 0.35, 1.90, 3.07 and 4.56 ppm

Any other information on results incl. tables

Table 1. Hydrolysis of Propane-1,2,3-triyl-3,5,5-trimethylhexanoate with intestinal-fluid simulant

Contact time (h)	Results (1)
	Triester (ppm)	Triester (%)	Diester (ppm) (2)	Acid (ppm)
0	24.34	100.0	0.96	0.35
1	19.72	81.0	1.07	1.90
2	18.67	76.7	1.10	3.07
4	17.22	70.8	1.13	4.56

 

(1) No Monoester was detected.

(2) Sum of two stereo isomers

 

Table 2. Mass balance of the ester hydrolysis

Contact time (h)	Results (1)
	Triester (µmol)	Diester (µmol)	Acid (µmol) (calc.) (1)	Acid (µmol) (exp.)
0	0.233	0.013	0.000	0.011
1	0.192	0.014	0.094	0.060
2	0.182	0.015	0.124	0.097
4	0.168	0.015	0.165	0.144

 

(1) Amount of diester is considered; one ester reacts to three acids.

 

Table 3. Recoveries of ester and acid

Results
ppm (calc.)	ppm (exp.)	Recovery (%)
Ester
23.91	28.32	118.5
Acid
9.86	10.89	110.4
21.92	25.57	116.7
38.36	43.67	113.8

Applicant's summary and conclusion

Conclusions:

Interpretation of results: bioaccumulation potential cannot be judged based on study results