2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium methyl sulphate

Endpoint summary

Description of key information

Assessment of toxicokinetic behaviour based on available data revealed no concern for ADME related effects. 

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

Introduction

Toxicokinetic parameters such as uptake, distribution, metabolism and excretion form the essential toxicological profile of a substance. An approximate indication of the toxicokinetic pattern can be gained from the physico-chemical properties taking into account the molecular weight, the number of atoms (hydrogen bond donors and acceptors), the solubility in solvents, log KOW, etc. and the results of basic toxicity testing of the test article. The assessment of the toxicokinetic properties of Basic Yellow 28 given below is based on the results obtained for, the following toxicological endpoints:

 

·        Acute oral toxicity in rats

·        Acute dermal toxicity in rats

·        In vivo skin irritation in rabbits

·        In vivo eye irritation in rabbits

·        Skin sensitization

·        Bacterial reverse mutation test

·        In vivo micronucleus test in rats

·        In vitro mouse lymphoma assay

·        28 day repeated dose toxicity study in rats

·        Screening test for toxicity to reproduction (OECD 421) in rats

All studies were carried out according to the principles of Good Laboratory Practice and/or met the requirements of the OECD and EU-Guideline for the Testing of Chemicals.

Physico-chemical properties

Name:                             Basic Yellow 28 Methyl Sulfate

CAS number:                    54060-92-3

CAS name:                         3H-Indolium, 2-[[2-(4-methoxyphenyl)-2-methylhydrazinylidene]methyl]-1,3,3-trimethyl-, methyl sulfate (1:1)

Physical state:                  solid, orange to red powder

Empirical formula:      C₂₀H₂₄N₃O.CH₃O₄S / C₂₁H₂₇N₃O₅S

Molecular weight:                433.52 g/mol                (<500 daltons=good absorption)

Water solubility:                8.8 g/L                           (= soluble in water)

Partition coefficient:           log Kow = -1.1             (<-0.4 or >5.6 = bad absorption):                            

Surface tension:               48.62 mN/m                 (<60 = surface active)

Melting range:                   111 - 159°C                  (= not volatile)

Vapor pressure:               3.3E-7 hPa at 25°C       (= not volatile)

Atom count (natoms):       24                                  (<70 = good bioavailability)

H-bond acceptor (nON):  4                                   (<10 =good bioavailability)

H-bond donor (nOHNH):  0                                   (<5 = good bioavailability)

Evaluation and Assessment

Basic Yellow 28 as the methyl sulfate salt has a low volatility (3.3E-7 hPa at 25°C) and should therefore not be released into air. Hence, no uptake of the substance via inhalation is expected.

Based on physico-chemical data and the results of toxicity studies, Basic Yellow 28 has a good oral and dermal bioavailability. According to its low log Kow, Basic Yellow 28 does not show any potential for bioaccumulation. This is confirmed by the results of the bioaccumulation modelling (BCFBAF v3.01), excluding a significant bioaccumulation potential of Basic Yellow 28.

Basic Yellow 28 was tested negative for genotoxicity in the Ames test, a mouse lymphoma assay and an in vivo micronucleus test. Therefore, a metabolisation towards genotoxic structures by mammalian species can most probably be excluded.

Summary

The results of basic toxicity testing give no reason to anticipate unusual characteristics with regards to the toxicokinetics of Basic Yellow 28. Bioaccumulation of Basic Yellow 28 can most probably be excluded due to the available data. Based on the results of genotoxicity assays, a metabolisation towards genotoxic metabolites can also be excluded for mammalian species.

The substance is therefore not considered to be of concern for ADME related effects.