Extract obtained from the shell of Theobroma cacao (Malvaceae) by co-extraction with ethanol and propylene glycol

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 15 March 2018 to 18 June 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: EU method A.24 (Partition coefficient (n-octanol / water), HPLC method)

Version / remarks:

2016

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Version / remarks:

2004

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)

Version / remarks:

1996

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

Extract obtained from the shell of Theobroma cacao (Malvaceae) by co-extraction with ethanol and propylene glycol

EC Number:

948-055-8

Molecular formula:

not applicable as it is a UVCB

IUPAC Name:

Extract obtained from the shell of Theobroma cacao (Malvaceae) by co-extraction with ethanol and propylene glycol

Test material form:

liquid: viscous

Details on test material:

- Physical appearance: dark brown to black viscous liquid
- Storage conditions: in refrigerator (2-8°C) protected from light

Study design

Analytical method:

high-performance liquid chromatography

Results and discussion

Partition coefficient

Partition coefficient 1

Key result

Type:

log Pow

Temp.:

20 °C

pH:

7

Remarks on result:

other: The log Pow and Pow values of this peak (70% area) could not be calculated because tr < tr of formamide.

Partition coefficient 2

Key result

Type:

log Pow

Partition coefficient:

-0.2

Temp.:

20 °C

pH:

7

Remarks on result:

other: Mean RT= 0.774 min. For the constituent with peak area of 25%.

Partition coefficient 3

Key result

Type:

log Pow

Partition coefficient:

0.6

Temp.:

20 °C

pH:

7

Remarks on result:

other: Mean RT= 1.145 min. For the constituent with peak area of 5.6%.

Details on results:

- Retention times of reference items used for calibration: see table below;
- Details of fitted regression line: log k' = 0.631 log Pow – 0.441 (r = 0.998, n=12);
- Chromatogram and graph of regression line attached;
- The chromatogram of test item showed one major peak and several small peaks.
- The log Pow and Pow values of the major peak could not be calculated because tr < tr of formamide.
- Average retention data for the test item: see table below;
- The value of log Pow obtained from duplicate measurements was within ± 0.1 log units.

Any other information on results incl. tables

Table: Results Partition coefficient n-octanol-water (HPLC method)

Substance	Retention time (min)			log Pow	Pow	Peak area (%)
	RT1	RT2	mean
Formamide (t0)	0.613	0.607	0.610
2-Butanone	0.928	0.927	0.928	0.3
Benzylalcohol	1.888	1.852	1.870	1.1
Nitrobenzene	3.849	3.764	3.807	1.9
Toluene	12.728	12.450	12.589	2.7
Bromobenzene	16.800	16.422	16.611	3.0
1,4-Dichlorobenzene	32.138	31.478	31.808	3.4
Test item – peak 1	0.578	0.577	0.578	n.a.	n.a.	70
Test item – peak 2	0.774	0.771	0.773	-0.2 (1)	0.61	25
Test item – peak 3	1.145	1.141	1.143	0.6	4.0	5.6

(1)   Estimated value, calculated by extrapolation of the calibration curve.

Applicant's summary and conclusion

Conclusions:

The log Pow at pH 7 and ca. 20°C for the constituent with peak area of 70%, 25% and 5.6% was determined to be <0.3, -0.2 and 0.6, resp.

Executive summary:

The partition coefficient (n-octanol/water) of the substance was determined using the HPLC method. The study was performed in accordance with EC A.24, OECD 117 and OPPTS 830.7570 and in compliance with GLP. Formamide was used as unretained substance. For the construction of the regression line, 6 references substances with known log Pow values (at ca. 20°C) ranging from 0.3 to 3.4 were used. Duplicate injections of unretained substance, reference substances and test item in an UPLC-UV system. The mobile phase was 40/60 (v/v) methanol/buffer pH 7 and the wavelength of detection was 210 nm. Each chromatogram of the test item showed three substance peaks. The major component (70% area) eluted before the unretained component and before the reference substance with log Pow of 0.3. From this it can be concluded that the log Pow for this component is < 0.3. Substituting the mean retention times of the other two peaks in the regression line yielded a log Pow values of -0.2 and 0.6. Pow= 0.61 and 4.0, resp.