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Physical & Chemical properties

Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13 December 2018 - 03 January 2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
GLP compliance:
yes
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
Name: Monalazone Disodium
Lot No. Purity Manufactured date Expiry Date
72617S >99% excluding water 7/26/2017 2/1/2019

Analytical method:
liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
1.46
Temp.:
25 °C
pH:
7.55
Key result
Type:
log Pow
Partition coefficient:
1.44
Temp.:
25 °C
pH:
7.55
Details on results:
The obtained retention times, capacity factors and corresponding log Pow values of reference substances obtained during each determination are presented as Table 1, Table 2 and Table 3. The calibration graphs of each determination are presented as Figure 1 to Figure 3.
Correlation coefficients (r) of calibration graphs of Determination 1, Determination 2 and Determination 3 were 0.9024, 0.9571 and 0.9038, respectively. Under each determination, test item solutions were injected to HPLC in duplicate and the partition coefficient of test item was calculated to be 1.46, 1.44 and 1.46 for Determination 1, Determination 2 and Determination 3, respectively (Table 4).
There was no variation among the values of partition coefficient obtained from Determination 1 and Determination 2, showing that repeatability of the method used was acceptable and the variation among values of partition coefficient obtained from 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 mean partition coefficient (n-octanol/water) of the test item, Monalazone Disodium was 1.45 (pH 7.55) at a temperature of 25ºC (Table 4).

TABLE 1.      Partition Coefficient (n-octanol/water) of Monalazone Disodium- Determination 1

Reference substance /

Test item

Repli-
cation No.

Retention time

(min.)

Mean Retention time (min.)

Capacity factor

(k)

log k

Log Pow

#

Thiourea

(Dead time, t0)

R1

1.575

1.576

-

-

-

R2

1.577

Acetanilide

R1

3.618

3.636

1.31

0.12

1.00

R2

3.654

Phenol

R1

4.680

4.676

1.97

0.29

1.50

R2

4.672

Phenacetin

R1

5.194

5.200

2.30

0.36

1.58

R2

5.206

Atrazine

R1

12.815

12.830

7.14

0.85

2.60

R2

12.844

Acetophenone

R1

8.075

8.078

4.13

0.62

1.70

R2

8.081

Methyl Benzoate

R1

15.157

15.210

8.65

0.94

2.10

R2

15.262

Monalazone Disodium

R1

5.031

5.040

2.20

0.34

1.46*

R2

5.049

TABLE 2.      Partition Coefficient (n-octanol/water) of Monalazone Disodium- Determination 2

Reference substance /

Test item

Repli-
cation No.

Retention time

(min.)

Mean Retention time (min.)

Capacity factor

(k)

log k

Log Pow

#

Thiourea

(Dead time, t0)

R1

1.571

1.570

-

-

-

R2

1.569

Phenol

R1

4.640

4.643

1.96

0.29

1.50

R2

4.645

Acetanilide

R1

3.622

3.620

1.31

0.12

1.00

R2

3.618

Phenacetin

R1

5.193

5.201

2.31

0.36

1.58

R2

5.209

Acetophenone

R1

8.092

8.082

4.15

0.62

1.70

R2

8.072

Methyl Benzoate

R1

15.111

15.129

15.129

0.94

2.10

R2

15.146

Benzene

R1

17.292

17.285

17.285

1.00

2.10

R2

17.277

Monalazone Disodium

R1

5.073

5.072

5.0722

0.35

1.44*

R2

5.071

Table 3 Partition Coefficient (n-octanol/water) of Monalazone Disodium - Determination 3

Reference substance /

Test item

Repli-
cation No.

Retention time

(min.)

Mean Retention time (min.)

Capacity factor

(k)

log k

Log Pow

#

Thiourea

(Dead time, t0)

R1

1.573

1.574

-

-

-

R2

1.574

Acetanilide

R1

3.601

3.602

1.29

0.11

1.00

R2

3.602

Phenol

R1

4.649

4.648

1.95

0.29

1.50

R2

4.647

Phenacitin

R1

5.200

5.193

2.30

0.36

1.58

R2

5.185

Acetophenone

R1

8.082

8.084

4.14

0.62

1.70

R2

8.086

Atrazine

R1

12.812

12.824

7.15

0.85

2.60

R2

12.836

Methyl Benzoate

R1

15.179

15.136

8.62

0.94

2.10

R2

15.092

Monalazone Disodium

R1

5.039

5.041

2.20

0.34

1.46*

R2

5.042

Table 4 Partition Co-efficient (n-octanol/water) of Monalazone Disodium

Determination

log Pow

Repeatability* 

(log units)

Reproducibility@

(log units)

1

1.46

0.02

0.00 to 0.02

2

1.44

3

1.46

Overall Mean

± s.d.

6.84

± 0.06

 
Conclusions:
The HPLC method was applied for the determination of the partition coefficient (Pow) of Monalazone Disodium. The mean partition coefficient (n-octanol/water) of the test item was 1.45 (pH 7.55) at a temperature of 25ºC.

Executive summary:

The objective of this study was to determine the partition coefficient (log Pow) for Monalazone Disodium following OECD 117 Guideline. Correlation coefficients (r) of calibration graphs of Determination 1, Determination 2 and Determination 3 were 0.9024, 0.9571 and 0.9038, respectively. Under each determination, test item solutions were injected to HPLC in duplicate and the partition coefficient of test item was calculated to be 1.46, 1.44 and 1.46 for Determination 1, Determination 2 and Determination 3, respectively

There was no variation among the values of partition coefficient obtained from Determination 1 and Determination 2, showing that repeatability of the method used was acceptable and the variation among values of partition coefficient obtained from 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 mean partition coefficient (n-octanol/water) of the test item, Monalazone Disodium was 1.45 (pH 7.55) at a temperature of 25ºC.

 

Description of key information

The mean partition coefficient (n-octanol/water) of the test item, Monalazone Disodium was 1.45 (pH 7.55) at a temperature of 25ºC.

Key value for chemical safety assessment

Log Kow (Log Pow):
1.45
at the temperature of:
25 °C

Additional information

The objective of this study was to determine the partition coefficient (log Pow) for Monalazone Disodium following OECD 117 Guideline.Correlation coefficients (r) of calibration graphs of Determination 1, Determination 2 and Determination 3 were 0.9024, 0.9571 and 0.9038, respectively. Under each determination, test item solutions were injected to HPLC in duplicate and the partition coefficient of test item was calculated to be 1.46, 1.44 and 1.46 for Determination 1, Determination 2 and Determination 3, respectively


There was no variation among the values of partition coefficient obtained from Determination 1 and Determination 2, showing that repeatability of the method used was acceptable and the variation among values of partition coefficient obtained from 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 mean partition coefficient (n-octanol/water) of the test item, Monalazone Disodium was 1.45 (pH 7.55) at a temperature of 25ºC.