Sodium ascorbate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-12-21 to 2010-03-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

yes

Remarks:

see Principles other than Guidelines

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

yes

Remarks:

see Principles other than guidelines

Principles of method if other than guideline:

Flask method was performed with abbreviated stirring times and the solubility was calculated from the individual solubilities in n-octanol and water

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Remarks:

Simplified Flask Method adapted to OECD 107

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

- Batch Number: TL00910581

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

< -4.2

Temp.:

21.9 °C

pH:

6.6

Details on results:

The n-octanol solubility of the test item was determined to be < 40.7 mg/L, which is below the concentration of the smallest calibration point.

Neither the HPLC-method according to OECD Guideline No. 117 nor the flask-shaking method according to OECD Guideline No. 107 were applicable for the determination of the partition coefficient of sodium ascorbate crystalline. Thus, the log Pow-value for the test item was estimated from its solubility in n-octanol and in water, respectively. The n-octanol solubility of the test substance was determined to be < 40.7 mg/L, which is below the concentration of the smallest calibration point (multiplied with the dilution factor). The partition coefficient, log Pow, of the test item was calculated from the individual solubilities in n-octanol and in water [1], respectively.

A typical chromatogram of the smallest calibration point is given in the attached Figure 5. A typical chromatogram of a sample solution in n-octanolis is given in the attached Figure 6. A typical HPLC chromatogram of a blank solution is shown in the attached Figure 7. The calibration curve and the data for test item-standards are given in the attached Figure 8 and Table 6. The correlation coefficient r² was 0.9946 (optimum 1.0000). This reflects the linearity of the HPLC-system within the calibration range of 4.066 µg/mL to 101.6 µg/mL of the test item.

[1] The solubility in water was taken from the main test.

Conclusions:

The partition coefficient, log Pow, of the test item was calculated from the individual solubilities in n-octanol and in water to be log Pow < -4.2 at 21.9 °C. The pH in the aqueous phase was 6.6.

Executive summary:

The partition coefficient, log Pow, of the test item was calculated from the solubilities in n-octanol determined in the preliminary test and in water (taken from the main test) to be: log Pow < -4.2 at 21.9 °C. The pH in the aqueous phase was 6.6.

Description of key information

The partition coefficient, log Pow, of the test item was calculated from the individual solubilities in n-octanol and in water to be log Pow  < -4.2 at 21.9 °C. The pH in the aqueous phase was 6.6.

Key value for chemical safety assessment

Log Kow (Log Pow):

-4.2

at the temperature of:

21.9 °C

Additional information

The partition coefficient, log Pow, of the test item was calculated from the solubilities in n-octanol determined in the preliminary test and in water (taken from the main test) to be: log Pow < -4.2 at 21.9 °C. The pH in the aqueous phase was 6.6.