L-Tyrosine, N-acetyl-3,5-diamino-O-(4-methoxyphenyl)-, ethyl ester

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

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:

no

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

ethyl (2S)-3-[3,5-diamino-4-(4-methoxyphenoxy)phenyl]-2-acetamidopropanoate

Cas Number:

440667-78-7

Molecular formula:

C20H25N3O5

IUPAC Name:

ethyl (2S)-3-[3,5-diamino-4-(4-methoxyphenoxy)phenyl]-2-acetamidopropanoate

Test material form:

solid: particulate/powder

Study design

Analytical method:

high-performance liquid chromatography

Results and discussion

Partition coefficient

Key result

Type:

log Pow

Partition coefficient:

0.912

Temp.:

25 °C

pH:

> 5 - < 6

Applicant's summary and conclusion

Conclusions:

The log POW of the test item L-Tyrosine, N-acetyl-3,5-diamino-O-(4-methoxyphenyl)-, ethyl ester is stated as 0.9 (mean).

Executive summary:

The study was performed using a HPLC with a C18 column. Six reference items with differ-ent retention times and thiourea for the determination of the dead time were used to pro-duce a calibration curve, since retention time on hydrophobic columns and POW are corre-lated. The reference items were chosen based on the results of the pre-test.

One vial was filled with the reference item mix and one vial with the test item solution. The vials were analysed using the HPLC with the program described below (chapter 4.3.2). First one injection from the solvent blank methanol/water 65/35 (v/v) was made. Then three in-jections were measured from the reference item mix, three injections from the test item and again three injections from the reference item mix. The pH of the eluent was 5 6, deter-mined with indicator paper.

For each reference item, the capacity factor k was calculated from the retention time of thiourea and the retention time of the respective reference item.
A calibration function (log k versus log POW, linear fit) was determined using the literature values for POW of the reference items and the retention times in the six determinations.

The chromatogram of the test item L-Tyrosine, N-acetyl-3,5-diamino-O-(4-methoxyphenyl)-, ethyl ester gave one peak with a retention time of 2.206 min (mean).
With the calibration function log k versus log POW, the corresponding log POW of the peak was calculated with: 0.912 ± 0.002 (mean ± standard deviation).
Therefore, the log POW of the test item L-Tyrosine, N-acetyl-3,5-diamino-O-(4-methoxyphenyl)-, ethyl ester is stated as 0.9 (mean).