Registration Dossier

Administrative data

Endpoint:
dissociation constant
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Study period:
18 Sep 2017 - 08 Jan 2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The test item is a UVCB and the experimental determination of the dissociation constants (e.g. Titration method, Spectrophotometric method) was, therefore, not possible. The calculation method was applied.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Details on test material:
- Physical appearance: pale yellow liquid
- Storage conditions: at room temperature

Results and discussion

Dissociating properties:
yes
Dissociation constantopen allclose all
No.:
#1
pKa:
1.8
Temp.:
20 °C
Remarks on result:
other: acidic group
No.:
#2
pKa:
14.7
Temp.:
20 °C
Remarks on result:
other: acidic group
No.:
#3
pKa:
0.8
Temp.:
20 °C
Remarks on result:
other: acidic group

Any other information on results incl. tables

The pKa values for three acidic groups in the molecular structure of the substance were calculated to be 1.8, 14.7, and 0.8 using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International, USA).

 

Peak nr.[1]

Content (%)[1]

Acidic

 

Basic

 

1

 

1.63

 

XYPSSH

 

 

pKa1.8

            

none

3

3.62

RRCHOH

 

pKa14.7

none

6[2]

 

3.62

 

XYPSOH

 

 

pKa0.8

 

none

            

[1]According to the Analytical report in Appendix 2.  (See background material)

[2]The chemical structures of peak nr 12 (5.36%) and peak nr. 18 (5.21%) were comparable to peak nr 6 and similar calculation results are expected. 

Applicant's summary and conclusion

Conclusions:
The pKa values for three acidic groups in the molecular structure of X-19657 were calculated to be 1.8, 14.7, and 0.8 using the Perrin calculation method.
Executive summary:

The test item is a UVCB and the experimental determination of the dissociation constants (e.g. Titration method, Spectrophotometric method) was, therefore, not possible. The Perrin calculation method was applied.

The pKa values for three acidic groups in the test item were calculated to be 1.8, 14.7, and 0.8.