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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Reliablity 2
Reference:
Composition 0
Qualifier:
according to
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
Test material information:
Composition 1
Specific details on test material used for the study:
Name: 6-Methyl-2-Thiouracil
Batch No: 151117
Purity 98.46%
Manufactured date 15.11.2017
Expiry Date 14.11.2019


Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
ca. -1.703
Temp.:
30 °C
pH:
ca. 6.2
Details on results:
The obtained retention times, capacity factors and corresponding log Pow values of reference substances are presented as Table 1, Table 2 and Table 3. The calibration graphs of each test are presented as Figures 1 to Figure 3. Correlation coefficients (r) of calibration graphs of Determination 1, Determination 2 and Determination 3 were 0.9867, 0.9866 and 0.9450, respectively. Under each determination, test item solutions were injected to HPLC in duplicate and the partition coefficient of test item were -1.85, -1.83 and -1.43 for Determination 1, Determination 2 and Determination 3, respectively (Table 4).
The obtained correlation coefficients of each test were in acceptable range, i.e., above 0.9. The variation among the values of partition coefficient obtained from Determination 1 and Determination 2 was well within the range of ± 0.1 log units, showing that repeatability of the method used was acceptable and the variation among Determination 1, Determination 2 and Determination 3 was
well within the range of ± 0.5 log units, showing that reproducibility of the method used was acceptable.
The partition coefficient of the test item, 6-methyl-2-thiouracil Technical was -1.80 (Table 4) and representative chromatograms are presented as Figure 4 to Figure 15.

TABLE 1.  Results of Determination 1

Reference substance / Chemical

 

Repli-
cation

Retention time (min.)

Mean Retention time (min.)

Capacity factor (k)

log k

logPow(1)

Thiourea (inert substance)

R1

2.413

2.407

-

-

-

R2

2.400

Acetanilide

 

R1

3.027

3.027

0.26

-0.59

1.0

R2

3.027

Aniline

 

R1

3.293

3.287

0.37

-0.43

0.9

R2

3.280

Diphenyl amine

 

R1

5.680

5.687

1.36

0.13

3.4

R2

5.693

Phenyl benzoate

 

R1

6.120

6.134

1.55

0.19

3.6

R2

6.147

Diphenyl ether

 

R1

7.667

7.680

2.19

0.34

4.2

R2

7.693

Biphenyl

 

R1

7.973

7.987

2.32

0.37

4.00

R2

8.000

6-Methyl-2-Uracil (Test item)

R1

2.520

2.527

0.05

-1.3

-1.85

R2

2.533

 

(1)  OECD Guideline No.:117 

(2)  Calculated

 


TABLE 2.  Results of Determination 2

Reference substance / Chemical

     Replication

Retention time (min.)

Mean Retention time (min.)

Capacity factor (k)

log k

logPow(1)

Thiourea (inert substance)

R1

2.400

2.400

-

-

-

R2

2.400

Acetanilide

 

R1

3.027

3.027

0.26

-0.59

1.0

R2

3.027

Aniline

 

R1

3.307

3.307

0.38

-0.42

0.9

R2

3.307

Diphenyl amine

 

R1

5.800

5.800

1.42

0.15

3.4

R2

5.800

Phenyl benzoate

 

R1

6.293

6.287

1.62

0.21

3.6

R2

6.280

Diphenyl ether

 

R1

7.867

7.867

2.28

0.36

4.2

R2

7.867

Biphenyl

 

R1

8.160

8.174

2.41

0.38

4.00

R2

8.187

6-Methyl-2-Uracil (Test item)

 

R1

2.520

2.520

0.05

-1.30

-1.83

 

R2

2.520

(3)  OECD Guideline No.:117 

(4)  Calculated

 

    

 


TABLE 3.  Results of Determination 3

Reference substance / Chemical

 

Replication

Retention time (min.)

Mean Retention time (min.)

Capacity factor (k)

log k

logPow(1)

Thiourea (inert substance)

R1

2.400

2.400

-

-

-

R2

2.400

Acetanilide

 

R1

3.040

3.040

0.27

-0.57

1.0

R2

3.040

Phenacetin

 

R1

3.147

3.147

0.31

-0.51

1.6

R2

3.147

Aniline

 

R1

3.307

3.307

0.38

-0.42

0.9

R2

3.307

Methyl benzoate

 

R1

4.507

4.507

0.88

-0.06

2.1

R2

4.507

Diphenyl amine

 

R1

5.853

5.867

1.44

0.16

3.4

R2

5.880

Phenyl benzoate

 

R1

6.320

6.327

1.64

0.21

3.6

R2

6.333

6-Methyl-2-Uracil (Test item)

 

R1

2.520

2.520

0.05

-1.30

-1.43

R2

2.520

(1)  OECD Guideline No.:117 

(2)  https://pubchem.ncbi.nlm.nih.gov/compound/phenacetin

(3)  https://pubchem.ncbi.nlm.nih.gov/compound/benzo_a_pyrene

(4)  Calculated

 

TABLE 1.                                                             Partition Co-efficient (n-octanol/water) of 6-methyl-2-                                                                                        thiouracil Technical

Determination

log Pow

Repeatability*  (log units)

Reproducibility@

(log units)

1

-1.85

-0.02

-0.42

2

-1.83

3

-1.43

Overall Mean

± s.d

 -1.703

±

0.24

 

 

Note:

*  Repeatability is the variation between Determination 1 and 2

     Repeatability = Log Powof determination I - Log Powof determination II

@   Reproducibility is the variation between Determination 1 and 3 and    Determination 2 and 3

     Reproducibility = Log Powof determination I - Log Powof determination III

 

 Please find the below mentioned curve in attched report.

FIGURE 1.       Calibration Curve - Determination 1

FIGURE 2. Calibration Curve - Determination 2

FIGURE 3.       Calibration Curve - Determination 3

FIGURE 4.       RepresentativeChromatogramof Dead –Time    Analysis usingThiourea

FIGURE 5.       Representative Chromatogram of Reference SubstanceAcetanilide

FIGURE 6.       Representative Chromatogram of Reference SubstanceAniline

FIGURE 7.   Representative Chromatogram of Reference Substance Diphenyl amine 

  

FIGURE 8.       Representative­ Chromatogram ofReference SubstancePhenyl benzoate

FIGURE 9.       Representative Chromatogram of Reference SubstanceBiphenyl

FIGURE 10.   Representative Chromatogram ofTest Item

                       

                           


 

 

Conclusions:
The mean partition coefficient (Pow) of the test substance was found to be POW -1.703 ± 0.24 at 30 ºC.
Executive summary:

The mean partition coefficient (Pow) of the test substance was found to be  POW   -1.703 ± 0.24 at 30 ºC.

Description of key information

Key value for chemical safety assessment

Log Kow (Log Pow):
-1.703
at the temperature of:
30 °C

Additional information