1,3,4-Octadecanetriol, 2-amino-, sulfate (2:1) (salt), D-ribo- (8CI)

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - HPLC Method)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

(2S,3S,4R)-1,3,4-trihydroxyoctadecan-2-aminium sulfate

EC Number:

917-270-9

Cas Number:

29790-50-9

Molecular formula:

C36H80N2O10S

IUPAC Name:

(2S,3S,4R)-1,3,4-trihydroxyoctadecan-2-aminium sulfate

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 62630012
- Expiration date of the lot/batch: 01.11.2002
- Purity: 94.0 %

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature in the dark

Study design

Analytical method:

high-performance liquid chromatography

Results and discussion

Partition coefficient

Key result

Type:

log Pow

Partition coefficient:

> 6.2

Temp.:

22 °C

pH:

10.5

Applicant's summary and conclusion

Conclusions:

The results of the Calculation method and the HPLC method were not in agreement. Since the HPLC method is a more accurate method than the Calculation method, the result of the HPLC method is reported as the partition coefficient (n-octanol/water), Pow, of Phytosphingosine (representative for Phytosphingosine Sulfate (PSS)). The partition coefficient (n-octanol/water), Pow, of Phytosphingosine (representative for Phytosphingosine Sulfate (PSS)) is >1.6 x 10^6 (log Pow > 6.2).

Executive summary:

Main test

The mobile phase was 60/40 (v/v) acetonitrile/Milli-Q water, and a refractive index detector was used. The column oven temperature was set to 22.0°C during the test. HPLC chromatograms of the Phytosphingosine test solution, the test substance blank solution (methanol) and the 2,4-DDT reference solution are provided. In the chromatograms of the 1840 mg/L Phytosphingosine test solution, which were recorded for 90 minutes, no test substance peak was observed. Under the same chromatographic conditions, the retention time of 2,4-DDT (log P. = 6.2) was 57.2 minutes. It was assumed that Phytosphingosine elutes after the reference substance 2,4 -DDT. The column oven temperature was set to 22.0°C during the test.

 

Additional test

In order to show that the test substance can be passed through the HPLC column and can be detected using a refractive index detector, a second mobile phase (60/40/0.05 (v/v/v) acetonitrile/Milli-Q water/trifluoracetic acid) was used. Methanol, the 2,4 -DDT solution, the test solution (in duplicate), the 2,4-DDT solution and methanol were injected using this mobile phase. One large test substance peak at a retention time of 3.49 minutes was observed in the chromatograms of the 1836 mg/L Phytosphingosine test solution. Therefore, it was concluded that at neutral pH, Phytosphingosine elutes after the reference substance with known log P of 6.2. Hence, the log Pow of Phytosphingosine is > 6.2 (P > 1.6 x 10^6). Under the conditions used, a non-ionised substance will elute later than an ionised one.

Because Phytosphingosine is ionised at neutral pH and non-ionised at pH 10.5, it was concluded that the test substance will not elute before the reference substance and that log Pow of Phytosphingosine (representative for Phytosphingosine Sulfate (PSS)) is also > 6.2 (P ow > 1.6 x 10^6) at pH 10.5.