Ammonium glycyrrhizate

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

estimation method based on individual solubilities in water and octanol as the experimental determination is technically not feasible.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

OECD 123 was attempted but low solubility in octanol made the experimental determination technically not feasible.
Therefore, log Pow was estimated by a calculation method based on individual solubilities in water (critical micelle concentration >= 160 mg/L for glycyrrhizic acid) and octanol (determined experimentally as < 20 mg/L).

GLP compliance:

yes

Type of method:

estimation method (solubility ratio)

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

Ammonium glycyrrhizate

EC Number:

258-887-7

EC Name:

Ammonium glycyrrhizate

Cas Number:

53956-04-0

Molecular formula:

C42H65NO16

IUPAC Name:

ammonium glycyrrhizate

Study design

Analytical method:

other: not relevant, estimation method (solubility ratio)

Results and discussion

Partition coefficient

Key result

Type:

log Pow

Partition coefficient:

<= -0.9

Remarks on result:

other: Temperature/pH not indicated

Any other information on results incl. tables

The item was found to have surfactant properties, thus the determination of the partition coefficient of the test item according to OECD 123 was proposed.The preliminary tests showed that the solubility of the test item in octanol is below 20mg/L.

Due to the very low solubility of the test item in octanol, the determination of the log Pow value is not feasible by the OCDE 123 method. Therefore, the Log Pow was estimated by a calculation method based on individual solubilities in water and octanol.

As the test item has surface-active properties, the water solubility should be considered as its critical micelle concentration (CMC). From the water solubilty study (see section 4.8.), the CMC of the test item is estimated to be 5 g/L. In the literature, some CMC values were measured (from the glycyrrhizic acid) between 0.16 to 4.4 g/L.

Since it was observed during the preliminary tests that the test item solubility in octanol was below 20 mg/L(exact value not determined), and the test item CMC value is higher than 160 mg/L (according to the literature), the maximal value of the log Pow can be estimated by the following calculation:

log Kow = log (solubilty in octanol/solubilty in water) <= log(20/160) <= -0.9

Applicant's summary and conclusion

Conclusions:

The log Pow of test item could not be determined experimentally due its surfactant properties and the low solubility in octanol. Therefore, the Log Pow was estimated by a calculation method based on individual solubilities in water and octanol. A maximal value of - 0.9 was calculated from the ratio of the measured solubility in octanol (<20 mg/L) and water (CMC of 160mg/L).