Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
10 November 2017 - 13 December 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
other: EU method A.24 (Partition coefficient (n-octanol / water), HPLC method)
Version / remarks:
2016
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
2004
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)
Version / remarks:
1996
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC method
Partition coefficient type:
octanol-water

Test material

Constituent 1
Chemical structure
Reference substance name:
Pregnenolone
EC Number:
205-647-4
EC Name:
Pregnenolone
Cas Number:
145-13-1
Molecular formula:
C21H32O2
IUPAC Name:
3-hydroxypregn-5-en-20-one
Test material form:
solid: particulate/powder
Details on test material:
- Physical appearance: white crystalline powder
- Storage conditions: at room temperature

Study design

Analytical method:
high-performance liquid chromatography

Results and discussion

Partition coefficientopen allclose all
Key result
Type:
Pow
Partition coefficient:
24 000
Temp.:
20 °C
Remarks on result:
other: Unbuffered mobile phase.
Key result
Type:
log Pow
Partition coefficient:
4.4
Temp.:
20 °C
Remarks on result:
other: Unbuffered mobile phase.
Details on results:
- Retention times of reference substances used for calibration: see table below;
- Details of fitted regression line: log k' = 0.325 x log Pow – 0.777 (r = 0.992, n=12);
- Graph of regression line and chromatograms: see illustration
- The chromatogram of the test item showed one substance peak
- Average retention data for test item: see table below.

Any other information on results incl. tables

Table: Results Partition coefficient n-octanol-water (HPLC method)

Substance

Retention time (min)

log Pow

Pow

tr,1

tr,2

mean

Formamide (t0)

0.966

0.951

0.959

 

 

Benzylalcohol

1.254

1.236

 

1.1

 

Toluene

2.495

2.454

 

2.7

 

1,4-Dichlorobenzene

3.223

3.169

 

3.4

 

Biphenyl

4.329

4.256

 

4.0

 

Dibenzyl

7.211

7.089

 

4.8

 

4,4’-DDT

18.838

18.526

 

6.5

 

Test item

5.236

5.208

5.222

4.4

2.4E4

Remark: the log Pow values of the reference substances are according to OECD TG 117.

Applicant's summary and conclusion

Conclusions:
The log Pow of the substance is 4.4 (at ca 20°C).


Executive summary:

The log Pow of the substance was determined using the HPLC method in a GLP study according to EC A.8, OECD 117 and OPPTS 830.7570. Formamide was used as unretained substance. Duplicate injections of unretained substance, 6 reference substances and test item in an UPLC-UV system. The mobile phase was 75/25 (v/v) methanol/water and the wavelength of detection was 210 nm. The chromatogram of the test item showed one peak. The corresponding log Pow (at ca 20°C) was determined to be 4.4 (Pow= 24000).