Registration Dossier

Toxicological information

Basic toxicokinetics

Currently viewing:

Administrative data

basic toxicokinetics in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference Type:
study report

Materials and methods

Objective of study:
Principles of method if other than guideline:
The quantitative evaluation of the substance and its degradation products in biological systems was performed in order to define and evaluate whether a substance gives rise to degradation products, particularly to 1-butanol.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Dibutyl phosphonate
EC Number:
EC Name:
Dibutyl phosphonate
Cas Number:
Molecular formula:
dibutyl phosphonate
Test material form:

Results and discussion

Main ADME results
the formation and presence of butanol following incubation of DBHP with biological matrices and S9 Rat liver fraction was supported using gas mass spectrometry with headspace extraction technique

Metabolite characterisation studies

Metabolites identified:
Details on metabolites:
1-butanol was identified following incubation with S9 rat liver metabolic fraction and biological matrices. The test item was no longer detected at the end of the study period.

Any other information on results incl. tables

A graph showing the calibration line for 1-butanol in the concentration range of 10-200 ppb was formed; the line of best fit was y = 271.12x + 6712 (R2 = 0.9971).

Furthermore, the ion chromatogram relative to the test item in a concentration of 1 ppb (LOD value of the method) by means of head space analysis confirmed the presence or absence of DBHP in the investigated samples and 1-butanol chromatogram detected in the sample under investigation.

The pure DBHP compound was also analysed, and its ionic chromatogram demonstrated the formation and presence in the pure butanol compound.

The table below shows the quantitative values detected in the samples under investigation.

Table 1: Quantitative determination of butanol and DBHP in samples under investigation.

Name Description Butanol (ppb) DBHP (ppb)
N7 Blank (NADPH + S9 + Dulbecco Buffer + 0.1% DMSO) blank n.d. n.d.
N1 (DBP + S9 + Dulbecco Buffer + 0.1% DMSO) T0 control 50.74 n.d.
N2 (DBP + S9 + Dulbecco Buffer + 0.1% DMSO) T60 control 52.43 n.d.
N3 T0 incubation n.1 44.43 n.d.
N4 T60 incubation n.1 50.55 n.d.
N5 T0 incubation n.2 50.65 n.d.
N6 T60 incubation n.2 52.78 n.d.

As seen in the table concerning quantitative results, a very similar level of butanol was found among the different types investigated in all the samples. However, the presence of DBHP was not found in any sample subjected to analysis. In the N7 sample (considered a blank reference and consisting of NADPH + S9 + Dulbecco Buffer + 0.1 % DMSO), no DBHP or butanol was detected.

It should be noted, in all the samples, the acetonitrile compound used for the preparation of the same is strongly interfered with.

Applicant's summary and conclusion

DBHP is metabolised to 1-butanol in the presence of biological matrices and S9 rat liver fraction.
Executive summary:

The potential metabolism of the test item to 1-butanol was evaluated in an in vitro experimental study. Samples were evaluated using gas mass spectrometry with headspace extraction technique, and 1-butanol and DBHP were quantified in the samples at 0 minutes and 60 minutes.

DBHP is metabolised to 1-butanol in the presence of biological matrices and S9 rat liver fraction.