Registration Dossier

Administrative data

Endpoint:
basic toxicokinetics, other
Type of information:
other: Assessment based on available physico-chemical data
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Assessment based on available physico-chemical data

Data source

Reference
Reference Type:
other company data
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Objective of study:
absorption
distribution
excretion
metabolism
Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
Assessment based on available physico-chemical data
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
CC(C)CC(C)(N=NC(C)(CC(C)C)C#N)C#N
Specific details on test material used for the study:
no actual test material used

Results and discussion

Main ADME resultsopen allclose all
Type:
absorption
Results:
see "any other information on results incl. tables" section
Type:
distribution
Results:
see "any other information on results incl. tables" section
Type:
metabolism
Results:
see "any other information on results incl. tables" section
Type:
excretion
Results:
see "any other information on results incl. tables" section

Any other information on results incl. tables

Data from in vivo studies, which were designed to identify the toxicokinetic properties of the substance, are not available.

This means, that absorption, distribution, metabolism and excretion (ADME) can only be derived from available physical-chemical data.

To estimate the toxicokinetic properties of the substance the following information was considered (cited from IUCLID6 data file, section 4):

Parameter

Value used for CSR

Molecular weight

248.4 g/mol

Melting point

52.1 °C

Boiling point

Decomposition/Self-Reactive

Density

0.9691

Vapour pressure

0.812 Pa (25 °C), calculated

Partition coefficient n-octanol/water (log POW)

3.37 (25 °C)

Calculated log POW(EPIWin)

 

Water solubility

9.37 mg/L (20 °C)

pH

Not relevant

pKa

Not relevant

Particle size

MMAD 157 µm

 

Absorption:

Based on above data the substance may be absorbed through the skin in relevant amounts (molecular weight < 500 g/Mol, -1 < log POW< 4, see EUROPEAN COMMISSION HEALTH & CONSUMER PROTECTION DIRETORATE-GENERAL: Guidance Document on Dermal Absorption Sanco/222/2000 rev. 7 19 March 2004).

The log POWis within the thresholds for dermal absorption and the molecular weight indicates a “small molecule”. Therefore relevant amounts of the substance may to be absorbed via the skin.

For exposure assessments a default value of 100 % of absorption after dermal exposure may be appropriate.

The uptake after direct inhalation of the substance may be of medium relevance due to the mean diameter of particles, which exceeds the maximum inhalable particle diameter of 10 µm by more than 5 times. Uptake by inhalation after evaporation is unlikely. The substance is a solid at room temperature and decomposes upon heating.

For exposure assessments a default value of 10 % of absorption via inhalation may be appropriate.

The absorption after oral ingestion cannot be calculated due to lack of data; by default absorption of 100 % may be appropriate, until specific data will be available, although such a high absorption is rather unlikely.

 

Distribution:

The substance is lipophilic and Protein binding is of relevance, resulting in a high distribution volume. Crossing of membrane barriers like the Blood/Brain barrier seems unlikely.

The LogPow indicates a low potential for bioaccumulation. Giving the low half life of the substance, the potential is rated as not present.

 

Metabolism and Excretion:

 

The half life of the substance lies within hours depending on the pH value and the temperature in aqueous medium. Without metabolic activity, the substance undergoes decomposition to N2and two radical molecules of 1‐cyano‐1,3‐dimethylbutyl.

The Azogroup in the unchanged molecule can be reduced by Phase-I-reductases like Cytochromes P450 leading to Aminogroups in the resulting fragments.

 

Targets for Phase-II-conjugation Enzymes can be the formed Aminogroups in metabolites. These groups are targets for Glutathione, Glucuronosyl-transferases and in the case of Amino-groups sulfotransferases and N-Acetyltransferases as well.

 

All of these reactions will increase the water solubility of the substance and improve urinary excretion, which may be the most relevant way of excretion for this substance.

Another relevant pathway for excretion may be by feces, especially for the fraction, which has not been absorbed in the gastrointestinal tract after oral uptake.

Excretion by exhalation does not seem to be relevant.

For the decomposition products similar excretion seems feasible. In the case of N2the major excretion way will be by exhalation.

Applicant's summary and conclusion

Conclusions:
An assessment based on available physico-chemical data is performed.
The relevant results are taken for risk assessment purposes:
dermal absorption: 100%
inhalative absorption: 10%
oral absorption: 100 %
Bioaccumulation: unlikely