3-acetoxymethylen-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July 26, 2012 to November 26, 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study (OECD107) with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

no

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

3-acetoxymethylen-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

EC Number:

213-485-0

EC Name:

3-acetoxymethylen-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

Cas Number:

957-68-6

Molecular formula:

C10H12N2O5S

IUPAC Name:

(6R,7R)-3-[(acetyloxy)methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Name: 7-Aminocefalosporansäure (7-ACA)
Lot no.: B146988

Study design

Analytical method:

high-performance liquid chromatography

Results and discussion

Partition coefficient

Type:

log Pow

Partition coefficient:

< -3.4

Temp.:

20 °C

pH:

ca. 4

Details on results:

The measurements of the Octanol phases produced a signal of the test item in the HPLC, which is not as clear as in the aqueous phases. Due to the presence of Octanol, the peak of the test item is overlaid by another signal (see Figure 4), which was not observed in the aqueous phases or in the calibration. Although the integration of the test item signal for the Octanol phases is more conservative and should lead to higher concentrations, the concentrations of the tests 1a to 2b were below the lowest reasonable calibration standard with a concentration of 0.054275 mg/L.

Any other information on results incl. tables

Table4 shows the results of the main test for the determination of the partition coefficient.

The values represented in the table are rounded values. The calculation was carried out with the original not rounded values.

Table4: Main test for the determination of the partition coefficient

Test	1a	1b	2a	2b	3a	3b
c (aqueous phases) [mg/L] (measured values)	131.13 / 131.03	131.97 / 130.94	84.70 / 84.54	83.58 / 83.45	262.25 / 261.76	257.66 / 257.41
c (aqueous phases, mean values) [mg/L]	131.09	131.46	84.62	83.52	262.01	257.54
pH value of aq. phases (24°C)	4.3	4.1	4.1	4.1	3.8	3.8
c (n-Octanol phases) [mg/L] (measured values)	<0.05 / <0.05	<0.05 / <0.05	<0.05 / <0.05	<0.05 / <0.05	0.08 / 0.08	0.08 / 0.08
c (n-Octanol phases, mean values) [mg/L]	<0.05	<0.05	<0.05	<0.05	0.08	0.08
Total recovery rate of the test item [%]	88	89	86	84	88	87
POW	<0.0004	<0.0004	<0.0006	<0.0006	0.0003	0.003
log POW	<-3.4	<-3.4	<-3.2	<-3.2	-3.5	-3.5
Mean value log POW	<-3.4

Applicant's summary and conclusion

Conclusions:

According to OECD Test Guideline 107 and EC No. 440/2008 Part A. Method A.8. the partition coefficient at 20 °C of test item 7-Aminocephalosporanic acid was determined to be:
log POW = < -3.4
POW = < 0.0004

Executive summary:

Before starting the main test for the determination of the partition coefficient the solvents n-Octanol, pre-saturated with distilled water, and distilled water, pre-saturated with n-Octanol, were prepared. Therefore 900 mL n-Octanol were shaken with 100 mL distilled water and 900 mL distilled water were shaken with 100 mL n-Octanol in a shaking apparatus for 24 h.

For the main test a stock solution of the test item in distilled water, pre-saturated with n-Octanol, was prepared. Therefore 59.39 mg of the test item were dissolved with 200 mL distilled water, pre-saturated with n-Octanol, at a temperature of 30°C.

From this stock solution 20 mL were added to six separating funnels. Different volumes of distilled water, pre-saturated with n-Octanol, and n-Octanol, pre-saturated with distilled water, were also added to the separating funnels (seeTable1).

Table1: Composition in the separation funnels

Test	V (stock solution) [mL]	V (H2O) [ml]	V (n-Octanol) [mL]
1a	20	20	40
1b	20	20	40
2a	20	40	20
2b	20	40	20
3a	20	--	40
3b	20	--	40

After adding the solvents the separating funnels were shaken for ten minutes with the shaking apparatus. After separating the phases in the funnels, both phases were removed from the funnels. Approximately 10 mL of each phase were centrifuged for 30 minutes at 20 °C with 15000 rpm.

The pH values of the aqueous phases were measured.

For the determination of the test item concentrations in the phases by means of HPLC samples of the aqueous phases were diluted from 1 mL to 25 mL with the eluent. The Octanol phases were injected undiluted.