3,3-bis(4-hydroxy-5-isopropyl-o-tolyl)phthalide

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:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 13. April 2004

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

published on 31. May 2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Commission Regulation (EU) 2016/266 adopted 7 December 2015 amending Regulation EC No. 440/2008, Method A.24 “Partition Coefficient (n-octanol/water), High Performance Liquid Chromatography (HPLC) Method

Deviations:

no

GLP compliance:

no

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

3,3-bis(4-hydroxy-5-isopropyl-o-tolyl)phthalide

EC Number:

204-729-7

EC Name:

3,3-bis(4-hydroxy-5-isopropyl-o-tolyl)phthalide

Cas Number:

125-20-2

Molecular formula:

C28H30O4

IUPAC Name:

3,3-bis(4-hydroxy-5-isopropyl-o-tolyl)phthalide

Details on test material:

- Storage conditions: Room Temperature (20 ± 5 °C)
- Expiry date: 16. Dec. 2019

Study design

Analytical method:

high-performance liquid chromatography

Results and discussion

Partition coefficient

Type:

log Pow

Partition coefficient:

3.682

Temp.:

25 °C

Remarks on result:

other: no further information available

Applicant's summary and conclusion

Conclusions:

The log Pow of the test item is stated as 3.682 at 25 °C.
The study was performed according to the OECD TG117, EU Method A.8 and EC Regulation Method A.24 without deviations and therefore considered to be of the highest quality (reliability Klimisch 1).The validity criteria are fulfilled.

Executive summary:

The partition coefficient of the test item was determined in a study according to OECD 117 resp. EU Method A.8. resp. EC Regulation Method A.24. The study was performed using a HPLC with a C18 column. Seven reference items with different retention times and thiourea for the determination of the dead time were used to produce a calibration curve, since retention time on hydrophobic columns and P_OW are correlated. 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. First one injection from the solvent blank methanol/water 75/25 (v/v) was made. Then three injections were measured from the reference item mix, three injections from the test item and again three injections from the reference item mix.
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 P_OW, linear fit) was determined using the literature values for P_OW of the reference items and the retention times in the six determinations. 

The chromatogram of the test item gave one peak. With the calibration function log k versus log P_OW, the corresponding log P_OW value of the test item peak was determined with:

 

Mean Area [mAU*min][1]	Relative Area [%]	Mean Retention Time [min]	log POW ±Standard Deviation
97.627	100	5.140	3.68±0.00

[1]mAU = milli absorbance units

 

This value is the mean ± standard deviation of three independent determinations.