1,4-bis[(2-ethyl-6-methylphenyl)amino]anthraquinone

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 06 June 2016 to 01 February 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

8.6

Temp.:

40 °C

pH:

5.3

Details on results:

The reference Pow-values in the OECD-guideline presumably refer to 25 °C. Even though the column temperature was 40 °C, this temperature is without influence on the result of the determination. The calibration was done referring to Pow- values of reference substances determined at 25 °C.
The chromatogram of the test item showed 1 signal eluting at 20.3 minutes. No calibration substance with a Pow–value above the value for the signal of the test item was available. For this reason the results for this signal was extrapolated.

The pKa values, calculated with the software ACD/Labs/Percepta 14.0.0 Release 2012 at the structure of the test item, were:

pKa(Acid): No acid pKa

First pKa(Base): - 4.5 +/- 0.2

Second pKa(Base): -0.9 +/- 0.2

Therefore the undissociated form (nonionic from) of the test item exists at a pH value > -0.9 and the test can be carried out in buffered water at pH 5.

Conclusions:

The partition coefficient (logPow) of the test item was determined to be 8.6 at 25 °C (pH 5.3).

Executive summary:

The partition coefficient of the test item was determined by the HPLC-method according to OECD TG 117, and under GLP.

The system was calibrated with six reference substances. The partition coefficient was determined to be 8.6 at 40°C, and is considered to also refer to 25 °C. All validity criteria were met.

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: non-GLP guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

> 6.2

Temp.:

25 °C

Remarks on result:

other: pH not recorded

Type:

log Pow

Partition coefficient:

8.76

Temp.:

25 °C

Remarks on result:

other: extrapolated

The following correlation equation was obtained from the logarithmic value of the retention times for the reference substances, log (Rt), and the logarithmic value of partition coefficients (log Pow) for each reference substance.

log Pow= 4.6940 log (Rt) + 1.4118 (correlation coefficient: r=0.99311)

The retention time of the reference substances (Rt) was corrected by subtracting the retention time of thiourea.

The retention times of the test substance were later than that of DDT. DDT was the reference substance having the maximum retention time of 11.259 min. The retention time of the test substances was measured to be 38.433 min ans was corrected by subtracting the retention time of thiourea (1.605) to a retention time of 36.828. For calculating the log Pow of the test substance the retention time was included in the above mentioned correlation equation and a value of log Pow =8.76 was determined.

Conclusions:

According to the OECD 117 the partition coefficient (log Pow) was determined to be above 6.2 at 25°C and with extrapolation of the linear standard curve determined by the reference substances a value of 8.76 for the log Pow of the test substance could be calculated.

Executive summary:

The partition coefficient (Pow) was determined according to the OECD Guideline 117 (HPLC method) at 25 °C. The retention time of the test substance were later than that of DDT. DDT was the reference substance having the maximum retention time of 11.259 min. The retention time of the test substances was corrected by subtracting the retention time of thiourea. The extrapolated log Pow-value was determined to be 8.76 at 25 °C.

Description of key information

The partition coefficient (logPow) of the test item was determined to be 8.6 at 25 °C (pH 5.3). (OECD 117, 2017)

Key value for chemical safety assessment

Log Kow (Log Pow):

8.6

at the temperature of:

25 °C

Additional information

Two studies conducted according to OECD 117 (HPLC method) are available. In Currenta 2011 (non-GLP), result was estimated from distant extrapolation as above the highest reference substance. In Currenta 2017, 2 additional reference substances, with higher and reliable logKow values, were used. This allowed a closer extrapolation, so the more recent, and GLP, study was considered as the key study.