Magnesium dihydrogen di-L-aspartate

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test:
In the experiments the partition coefficients were determined in the 1-octanol-water system.
The three-component 1-octanol-water-amino acid system was employed in the partition experiments.

- Short description of test conditions:
A given amount of water - saturated octanol (30 to 250 mL) was added to the amino acid solution (usually 0.1 mol dm-3) in octanol—saturated water (3 to 5 mL). This system was shaken in 5 min intervals with 10-fold inversion on an Erlenmeyer flask (usualy 250 mL) over a period of 1 h. The two phases were carefully separated, their volumes were measured and the concentration of amino acid was determined in the aqueous phase. The distribution coefficients for the amino acids in the 1-octanol-water system were calculated from the values obtained for the concentration of amino acid and the phase volumes. The analytical methods included polarography, photometry and potentiomctric titrations. The distribution coefficients of most of the amino acids were determined photometrically in the visible region using the ninhydrin reaction. The absorbance was read at 575 nm.

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

photometric method

Key result

Type:

log Pow

Partition coefficient:

-3.89

Remarks on result:

other: pH and measuring temperature were not reported

Conclusions:

According to the publication of Chmelik et al., 1991, the partition coefficient log Kow of L-aspartic acid was determined using the flask method and revealed a value of -3.89.

Executive summary:

In the study of Chmelik et al. (1991) the partition coefficient of L-aspartic acid was determined using the flask method. A given amount of water - saturated octanol (30 to 250 mL) was added to the amino acid solution (usually 0.1 mol dm-3) in octanol-saturated water (3 to 5 mL). This system was shaken in 5 min intervals with 10-fold inversion on an Erlenmeyer flask (usualy 250 mL) over a period of 1 h. The two phases were carefully separated, their volumes were measured and the concentration of amino acid was determined in the aqueous phase. The distribution coefficients for the amino acids in the 1-octanol-water system were calculated from the values obtained for the concentration of amino acid and the phase volumes. The analytical methods included polarography, photometry and potentiomctric titrations. The distribution coefficients of most of the amino acids were determined photometrically in the visible region using the ninhydrin reaction. The absorbance was read at 575 nm. Ther logPow was determined to be -3.89 for aspartic acid.

Reference 2

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

2019-09-06

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source

Justification for type of information:

1. SOFTWARE
Estimation Programs Interface Suite™ for Microsoft® Windows v4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.
2. MODEL (incl. version number)
KOWWIN v1.68
3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES: O=C(O)C(N)CC(=O)O
CAS-No.: 56-84-8
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Please refer to the 'attached justification' section for more detailed information
5. APPLICABILITY DOMAIN
Please refer to the 'attached justification' section for more detailed information
6. ADEQUACY OF THE RESULT
Please refer to the 'attached justification' section for more detailed information

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Software tool(s) used including version: Estimation Programs Interface Suite™ for Microsoft® Windows v4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.
- Model(s) used: KOWWIN v1.68
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

GLP compliance:

no

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

-4.32

Temp.:

25 °C

Remarks on result:

other: QSAR calculation, no pH reported

Conclusions:

The logPow was estimated using using the software KOWWIN Version v1.68, contained in the EPI Suite v4.11 programme of the U.S. Environmental Protection Agency. The calculated logPow is -4.32.

Executive summary:

The logPow was estimated using using the software KOWWIN Version v1.68, contained in the EPI Suite v4.11 programme of the U.S. Environmental Protection Agency. The calculated logPow is -4.32.

Description of key information

The partition coefficient was determined either experimentally by Chmelik et al. (1991) or by QSAR estimation. The experimentally determined partition coefficient is-3.89; temperature and pH during the measurement were not reported. The estimated partition coefficient was determined to be -4.32 at 25 °C. Both logPow were in the same order of magnitude, thus the experimentally determined logPow is regarded the most accurate and used for further calculations.

Key value for chemical safety assessment

Log Kow (Log Pow):

-3.89

Additional information

The partition coefficient was determined in the 1-octanol-water system. The three-component 1-octanol-water-amino acid system was employed in the partition experiments. A given amount of water - saturated octanol (30 to 250 mL) was added to the amino acid solution (usually 0.1 mol dm-³) in octanol-saturated water (3 to 5 mL). This system was shaken in 5 min intervals with 10-fold inversion on an Erlenmeyer flask (usualy 250 mL) over a period of 1 h. The distribution coefficients for the amino acids in the 1-octanol-water system were calculated from the values obtained for the concentration of amino acid and the phase volumes. The distribution coefficients of most of the amino acids were determined photometrically in the visible region using the ninhydrin reaction. The determined partition coefficient for aspartic acid was -3.89.

Additionally, the partition coefficient of aspartic acid was determined by QSAR estimation using Estimation Programs Interface Suite™ for Microsoft® Windows v4.11. US EPA, KOWWIN v1.68. The established partition coefficient is -4.32 at 25 °C. Both logPow values are in the same order of magnitude indicating a reliable QSAR estimation. The additionally contained magnesium ion in the test item is not considered to alter the partition coefficient to a huge extent.

For the determination of other physicochemical properties or environmental fate the published logKow is considered the most accurate value.