Registration Dossier

Administrative data

Endpoint:
water solubility
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Study period:
Testing was conducted between 29 April 2009 and 17 June 2009.
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Date of Signature: 04/03/09 Date of Inspection: 19/08/08
Type of method:
flask method

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Sponsor's identification : PDE-28
Description : red powder
Purity : 97%
Batch number : 1RF-8017
Date received : 23 March 2009
Storage conditions : room temperature, in the dark

Results and discussion

Water solubility
Water solubility:
> 0 g/L
Temp.:
20 °C
Details on results:
Preliminary test:

The preliminary estimate of water solubility was less than 1.0 x 10-4 g/l.

Any other information on results incl. tables

The mean peak areas relating to the standard and sample solutions are shown in the following table:

Table 2:

Solution

MeanArea

Standard 2.00 mg/l

31.590

Standard 2.02 mg/l

28.080

Standard blank

none detected

Sample blank

none detected

Sample 1A

none detected

Sample 1B

none detected

Sample 2A

none detected

Sample 2B

none detected

Sample 3A

none detected

Sample 3B

1.162

Sample 3B

1.162

The concentration (g/l) of test material in the sample solutions is shown in the following table:

Table 3:

Sample Number

Time Shaken at

~ 30ºC (hours)

Time Equilibrated at 20ºC (hours)

Concentration (g/l)

Solution pH

1

24

24

<1.0 x 10-4

7.0

2

48

24

<1.0 x 10-4

7.0

3

72

24

<1.0 x 10-4

7.0

Overall result:Less than 1.0 x 10-4 g/l at 20.0 ± 0.5ºC

Discussion:

The reduced mean recovery of 54.7% (triplicate recoveries of 38.7, 60.1 and 65.4%) was considered acceptable in this case, as essentially the procedural recoveries have been taken as a demonstration of limit of quantification. The limit value reported for all sample solutions has therefore originated from the concentration at which the analytical procedure has been successfully validated to detect the test material. 

Although on analysis, a very minor test material response was observed in sample 3, duplicate B only, even when corrected for the minimum recovery achieved during validation procedural recoveries; the resulting concentration was negligible. Therefore a common limit value, as defined above, was reported for this sample also.

A supernatant free from excess, un-dissolved test material could not be achieved for this test material by centrifugation alone. It was therefore necessary to filter the solutions before analysis. This was performed using glass fibre filters and a glass vacuum filtration apparatus, thus excluding contact with any filter membranes (such as nylon or cellulose) and/or filter bodies which may have stripped test material from solution by lipophilic adsorption.

The preliminary water solubility test indicated that the column elution method should have been performed as the solubility was less than 1 x 10-2g/l. However, in the absence of a suitable volatile organic solvent in which to dissolve the test material, it was not possible to use this method. Experience has shown that when test material is coated on to glass beads as a suspension, as opposed to a true solution, the test material breaks away from the support material, and then either compacts and blocks the system or migrates to the sample solution reservoir, either way invalidating the test.


Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): insoluble (< 0.1 mg/L)
The water solubility of the test material has been determined to be less than 1.00 x 10-4 g/l of solution at 20.0 ± 0.5°C.

Executive summary:
Water Solubility: Less than 1.0 x 10-4g/l of solution at 20.0 ± 0.5°C, using the flask method, Method A6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008.