Kombucha

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 13 July 2022 to 14 July 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

other: Commission Regulation (EU) 2016/266 adopted 7 December 2015 amending Regulation EC No. 440/2008, Method A.24 “Partition Coefficient (N-OCTANOL/WATER), HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) METHOD

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

0.3 - <= 1.3

Temp.:

25 °C

pH:

4

Details on results:

The chromatogram of the test item consists of four peaks. The retention time of the first two peaks lay below the retention time of thiourea, so no log POW could be calculated. With the calibration function log k versus log POW, the corresponding log POW values of the third and the fourth peak were determined with. Since the third peak elutes before the reference substance with the lowest log Pow, 2-Butanone (log POW = 0.3) and thus lies outside the calibration range, the log Pow can only be extrapolated. The log POW of the fourth peak could also be calculated and gave a log POW of 1.3.
Using the correlation log k / log POW, the log POW of the test item was as <0.3 – 1.3.

Peak	Measurement No.	k	logk	log Pow
1	1	-0.2343	n.c.	n.c.
	2	-0.2400	n.c.	n.c.
	3	-0.2457	n.c.	n.c.
	Mean			n.c.
	Standard deviation			n.c.
2	1	-0.0457	n.c.	n.c.
	2	-0.0457	n.c.	n.c.
	3	-0.0457	n.c.	n.c.
	Mean			n.c.
	Standard deviation			n.c.
3	1	0.1771	-0.7517	0.169
	2	0.1771	-0.7517	0.169
	3	0.1771	-0.7517	0.169
	Mean			0.169
	Standard deviation			0.000
4	1	0.4286	-0.3680	1.333
	2	0.4286	-0.3680	1.333
	3	0.4286	-0.3680	1.333
	Mean			1.333
	Standard deviation			0.000

log POW was calculated from the capacity factor as follows:
log POW = (log k + 0.8075) / 0.3297

Conclusions:

Variations in the retention times of reference items and test item are very small. Therefore a stable configuration of the HPLC-column can be assumed. The correlation log k/log POW is good: the coefficient of determination r2 was calculated with 0.9949. This value was considered as sufficiently high to use the calibration function for the determination of the log POW of the test item Kombucha.
The chromatogram of the test item consists of four peaks. The retention time of the first two peaks lay below the retention time of thiourea, so no log POW could be calculated.
The log POW of the third peak could be calculated but retention time of the third peak lay below the reference substance with the lowest log Pow, 2-Butanone (log POW = 0.3) and thus lies outside the calibration range. Therefore, the log POW can only be extrapolated. The log Pow of the fourth peak could also be calculated and gave a log POW of 1.3.

No observations were made which might cause doubts concerning the validity of the study outcome.

Description of key information

The partition coefficient was determined in the range of <0.3 -1.3 at 25°C (OECD 107)