Methyl-1H-benzotriazole

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

other: toxicokinetic assessment

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: toxicokinetic assessment based on physicochemical data and available studies.

Data source

Reference

Reference Type:

other: toxicokinetic assessment

Title:

Unnamed

Year:

2012

Materials and methods

Objective of study:

toxicokinetics

Principles of method if other than guideline:

Assessment of the toxicokinetic behaviour of the substance to the extent that can be derived from the relevant available information,Regulation (EC) No 1907/2006, Annex VII, 8.8.1

Test material

Test material information

Constituent 1

Reference substance name:

Methyl-1H-benzotriazole

EC Number:

249-596-6

EC Name:

Methyl-1H-benzotriazole

Cas Number:

29385-43-1

Molecular formula:

C7H7N3

IUPAC Name:

5-methyl-1H-1,2,3-benzotriazole

Results and discussion

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 IUCLID5 data file, section 4):

Parameter	Value used for CSR
Molecular weight	133.15 g/mol
Melting point	84-87 °C
Boiling point	> 350 °C (at 1,1013 hPa)
Density	1.13 g/cm^3(at 20 °C)
Vapour pressure	0.004 kPa (at 20 °C)
Partition coefficient n-octanol/water (log POW)	1.08 (at 25 °C)
Water solubility	4 g/L (at 25 °C)
pH	5-6
pKa	8.85 (at 25 °C)
Particle size	>1400 µm

 

Absorption:

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

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 low relevance due to the high mean diameter of particles, which significantly exceeds the maximum inhalable particle diameter of 10 µm. Uptake by inhalation after evaporation is unlikely, the substance is a solid at room temperature and has a very high boiling point together with a very low vapour pressure.

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

Distribution:

The substance is neither highly lipophilic nor highly hydrophilic the fact of which makes an estimation on which body compartment would be preferred for distribution n the human body practically impossible such that a more detailed description is futile.

Due to the log Pow of 1.44 only a low potential for bioaccumulation is expected.

Metabolism and Excretion:

Metabolic conversions at the tolyl moiety or the triazine ring are quite unlikely. The aromatic rings can be hydroxylated by certain phase I metabolic enzymes but this will happen to a small proportion.

There are no structural elements likely to undergo Phase II metabolism reactions. Typical Phase II metabolic enzymes like sulfotransferases, acetyltransferases and glucuronosyltransferases can only affect after Phase I metabolic reactions.

 

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

But even when the water solubility stays low, a renal excretion of the unchanged molecule is possible.

Another relevant pathway for exretion 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.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): low bioaccumulation potential based on study results
Based on the physicochemical data the toxicokinetic properties of Tolyltriazole are assesssed.

Executive summary:

Absorption: for the dermal and oral route, an absorption of 100% are assumed,

for the inhalative route no relevant absorption is estimated and 10% are assumed.

Distribution: no information

Metabolism and Excretion: no Phase II reactions may occur.

Renale and fecal excretion are the prominent excretion routes.