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Diss Factsheets

Administrative data

Link to relevant study record(s)

Description of key information

No experimental studies of the absorption, distribution, metabolism or elimination of Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chloride (CAS No. 3068-39-1; EC No. 221-326-1) in mammals are available. However, the physical chemical properties and the existing toxicology studies on the substance have been used to infer as far as possible, its potential toxicokinetics.

 

The substance Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chloride is a mono-constituent substance. I is a dark red powder, with a D50 value determined to be 54.89 μm. Its molecular weight (MW) is 464.984 g/mol. The substance is water-soluble (18.9 g/L at 20°C), and its partition coefficient (Log Kow/Log Pow) is 1.7. The substance is not readily biodegradable.

 

Absorption

The moderate Log Pow would favour oral absorption however, Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7 -dimethylxanthylium chloride is a quite large substance (MW464.984 g/mol and particle size D50 of 54.89 μm) although it is quite well water-soluble. At all pH values considered (i.e., 4, 7 and 9), the hydrolysis half-lives of the substance were very long thus indicating that the parent substance would be responsible for systemic effects. Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chloride is classified into category 1 for eye irritation, and repeated-dose oral studies also evidenced portal-of-entry effects. Signs of systemic toxicity were however observed, both in the acute oral toxicity study and in the repeat-dose oral toxicity study. In accordance with ECHA guidance, oral absorption is assumed to be 50% for human health risk assessment purposes.

 

As for oral absorption, the moderate Log Pow would favour absorption by inhalation. Results of the acute inhalation study requiring early sacrifice of several animals and classification as acute cat. 2, and the small Mass Median Aerodynamic Diameter (MMAD) obtained in this study indicate that when the dimension of bulk Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chloride is reduced, the substance is well absorbed following inhalation. In the absence of any quantitative data, for human health risk assessment purposes absorption by inhalation of Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chlorideis assumed to be 100%.

 

All physical-chemical properties of Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chloride suggest that the substance, although a solid and with a rather high molecular weight, is likely to be readily absorbed through the skin. This is further supported by the fact that Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chloride is a moderate skin sensitizer, and this property can also enhance dermal penetration. Therefore, for human health risk assessment dermal absorption is estimated at the same level of oral absorption i.e. 50%.

 

Distribution

Observation of “red colourisation of all the internal tissues” noted at necropsy in the acute oral toxicity study suggests that Basic Red 1:1/3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthylium chloride was widely distributed following oral administration.

 

Metabolism and Excretion

No information is available on the fate of any absorbed material and in vitro genotoxicity studies showed no quantitative difference in toxicity between exposures in the absence of exogenous metabolism and those in the presence of exogenous metabolism (using rat liver S9 fraction).

In addition to portal-of-entry effects in the stomach (and in the lungs, due to suboptimal gavage), the repeat-dose oral toxicity study showed some non-adverse effects in the kidney of females treated at 15 mg/kg/day thus suggesting some renal clearance/urinary excretion has occurred. Based on the relatively high molecular weight, faecal excretion via the bile is also likely to occur.

 

The potential of bioaccumulation is considered low.

Key value for chemical safety assessment

Bioaccumulation potential:
low bioaccumulation potential
Absorption rate - oral (%):
50
Absorption rate - dermal (%):
50
Absorption rate - inhalation (%):
100

Additional information