Lupine, L. albus, ext.

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 30th, 2016 to October 13th, 2016.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method. No deviation was reported. Test substance is adequately specified. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EU A.24

Deviations:

no

Remarks:

Council Regulation (EC) No 2016/266 of 7. December 2015, Method A.24 “Partition Coefficient (n-Octanol//Water), High Performance Liquid Chromatography (HPLC) Method”

GLP compliance:

no

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

< 0.3

Temp.:

25 °C

pH:

7

Remarks on result:

other:

Remarks:

pH reported in the Certificate of Analysis

Details on results:

The partition coefficient (n-octanol/water) (log Pow) of test substance was determined at test temperature of 25 °C

Results and discussion

1-Preliminary test

HPLC chromatogram

 

Retention time (minutes)
1.18 (beginning of the peak)
1.59 (middle of the peak)
1.81 (end of the peak)

The solution of test item gave one peak between 1.18 and 1.81 minutes.

 

2-Reference substances

The determination of retention times (t_r) of the reference items was made based on two replicates a and b. The obtained values are presented in the following table.

 

Substances	tr Replicate a	tr Replicate b	Mean (3)	Amplitude (4)	Uncertainty (5)	Conformity (6)
Uracil	1,59	1,59	1,590	0	0,2226	yes
2-butanone	2,08	2,08	2,080	0	0,2912	yes
2-pentanone	2,53	2,53	2,530	0	0,3542	yes
Benzonitrile	2,85	2,84	2,845	0,01	0,3983	yes
Cinnamic alcohol	3,39	3,36	3,375	0,03	0,4725	yes
Cinnamic acid	3,65	3,64	3,645	0,01	0,5103	yes
Ethyl benzoate	6,87	6,8	6,835	0,07	0,9569	yes
Benzyl benzoate	18,12	17,75	17,935	0,37	2,5109	yes

 

With the following formulas:

 

Mean =  (tra + tr b) / 2           (3)

Amplitude = I tra-trb I           (4)

Uncertainty = Mean x Srx f(2) / 100  (5)

 

Conform if (4) < (5)                             (6)

 

With:

-     factor of critical extend, determined by internal method: Q-ANA-I-081: = 2.8

-   SILAB repeatability factor, determined on several SILAB products and checked every years by Interlab test:= 5

 

By using the formula (1), the capacity factor (k), the Log P_owand the curve Log (k) = f (Log(P_ow)) can be determined.

 

Substances	Mean retention time (minutes)	Capacity factor (k)	Log k	Log Pow
Uracil	1,590	0	/	/
2-butanone	2,080	0,308	-0,511	0,3
2-pentanone	2,530	0,591	-0,228	0,9
Benzonitrile	2,845	0,786	-0,103	1,6
Cinnamic alcohol	3,375	1,113	0,050	1,9
Cinnamic acid	3,645	1,289	0,111	2,1
Ethyl benzoate	6,835	3,277	0,518	2,6
Benzyl benzoate	17,935	10,164	1,012	4

 

Equation of the regression:

 

Log k = 0.4163 x Log P_ow- 0.6755

 

With a coefficient of determination r²= 0.9736

And a correlation coefficient r = 0.9867

The correlation coefficient of 0.9867 > 0.9 (typically correlation coefficient according to the guideline) and is acceptable therefore.

 

3-Test item

a)    Measurements and calculation

Three injections of the solution of test item were made. The obtained chromatograms are presented in the report attached.

 

Superposition of the three curves

 

The measured retention times obtained at the beginning and at the end of the peak of test item are presented in the following table:

 

Injection		Retention time (minutes)	Capacity factor (k)	Log k	Log Pow
1	Beginning of the peak	1.15	-0.2767	*
	End of the peak	1.80	0.1321	-0.8792	-0.49
2	Beginning of the peak	1.15	-0.2767	*
	End of the peak	1.80	0.1321	-0.8792	-0.49
3	Beginning of the peak	1.15	-0.2767	*
	End of the peak	1.80	0.1321	-0.8792	-0.49

* The retention times of these measurements were lower than the retention time of Uracil which was used for determination of the dead time of the method.

 

b)    Results and discussions

Due to the nature of test item which is an UVCB (substances of Unknown or Variable composition, Complex reaction products or Biological materials), a peak is measured between 1.15 and 1.80 minutes.

As the retention of the beginning of the peak was lower than the dead time, the value of Log P_owwas determined by using the regression equation on the Log k found thanks to the retention time of the end of the peak. The calculated log Pow of

test item

wa s < -0.49.

Even if the correlation coefficient r = 0.9867 is good, all measurements were lower than the retention time of the reference substance with the lowest partition coefficient (0.3) i.e. 2-butanone.

So, the partition coefficient n-octanol/water of test item is stated as < 0.3.

Conclusions:

According to OECD method No. 117 and EU A.24, the partition coefficient n-octanol/water (Log Pow) of test item is stated as lower than 0.3.

Executive summary:

A non-GLP study was conducted according to OECD 117 and EU. A.24 to determine the partition coefficient of the substance.

The study was performed using an HPLC/RI detector with a C18 column.

Seven reference items with different retention times and uracil, for the determination of the dead time, were used to establish a calibration curve.

This calibration curve, log k versus log Pow, was obtained from the known Log P_owvalues of the reference items as reported in theOECD117/EU-method A.24 and the capacity factor k, calculated from the retention time of the respective reference items and uracil.The calibration curve was validated considering the correlation coefficient 0.9867 > 0.9. All measurements showed that the substance was eluted at a retention time lower than the retention time of the reference substance with the lowest partition coefficient (0.3), i.e. 2-butanone. So, according to the OECD method 117/EU A.24, the partition coefficient n-octanol/water of the substance was stated as < 0.3.

Description of key information

The partition coefficient n-octanol/water was stated as < 0.3.  

Additional information

A non-GLP study was conducted according to OECD 117 and EU. A.24 to determine the partition coefficient of the substance.

Thestudy was performed using an HPLC/RI detector with a C18 column.

Seven reference items with different retention times and uracil, for the determination of the dead time, were used to establish a calibration curve.

This calibration curve, log k versus log Pow, was obtained from the known Log P_owvalues of the reference items as reported in the OECD117/EU-method A.24 and the capacity factor k, calculated from the retention time of the respective reference items and uracil.The calibration curve was validated considering the correlation coefficient 0.9867 > 0.9. All measurements showed that the substance was eluted at a retention time lower than the retention time of the reference substance with the lowest partition coefficient (0.3), i.e. 2-butanone. So, according to the OECD method 117/EU A.24, the partition coefficient n-octanol/water of the substance

was stated as < 0.3.