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Description of key information

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

Evaluation and Assessment of the Basic Toxicokinetic Properties of Reaktiv Rot F‑66813

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 (solubility in solvents, log POW, hydrolytic stability) and the results of basic toxicity testing of the test article. The assessment of the toxicokinetic properties of Reaktiv Rot F‑66813 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

·   Skin sensitization in guinea pigs

·   Bacterial reverse mutation test

·   In vivo micronucleus test in mice

·   Subacute (28-day) oral toxicity in rats

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

Physico-chemical properties

The dye Reaktiv Rot F‑66813 has a molecular weight of 1092.3 g/mol. It is characterized by a high water solubility of > 200 g/l and a low partition coefficient (log Kow = -3).

Toxicological Profile:

Reaktiv Rot F‑66813 was tested for acute oral toxicity in male and female Wistar rats. After application of 2000 mg/kg body weight by gavage, neither lethality nor any clinical symptoms occurred. Beside a slight diarrhoea, red discoloured faeces and tray/bedding was observed. Other macroscopically visible changes were not observed. Based on the results of this study the oral medial lethal dose (LD50) of Reaktiv Rot F 66813 in the rat is greater than 2000 mg/kg body weight. Dermal treatment with 2000 mg/kg body weight caused also neither mortality nor symptoms of toxicological relevance. Exclusively the surface of the skin was red discoloured to a smaller or larger extend. There were no macroscopically visible changes in all animals killed at study end. Due to the hydrophilic properties of Reaktiv Rot F‑66318 and based on the results of the acute dermal toxicity study as well as the skin irritation and contact sensitization data, it is most likely that Reaktiv Rot F‑66318 has no significant dermal absorptive potential.

Reaktiv Rot F‑66318 was neither mutagenic in the standard Ames Test inSalmonella typhimurium(TA 100, TA1535, TA1537, TA1538, TA98) orEscherichia coli(WP2uvrA) nor in the preincubation test according to Prival with or without metabolic activation system. Reaktiv Rot F‑66318 was also negative in the in vivo micronucleus test in mice.

Based on the results of a subacute (28-day) oral toxicity study with Reaktiv Rot F‑66318, daily administration of doses up to 1000 mg/kg body weight to rats did not cause compound related mortality. Body weight development, haematological and clinical parameters as well as organ weights were unaffected. Faeces of animals of the 1000 mg/kg/day test group were red discoloured, from day 6 onwards. Urine was red-brown discoloured in all animals of the 1000 mg/kg/day test group.

Necropsy revealed red discoloration of the kidneys in all animals of the 1000 mg/kg/day test group. Additionally the testes of the males were red discoloured.

Microscopic examination revealed resorption vacuoles with a homogenous content in the tubular epithelial cells of the convoluted segment of the proximal tubulus of the renal cortex in two female animals of the highest dose group. This finding indicates a re-absorption of the dye from the primary urine and its intracellular lysosomal deposition.

A deposition of substance in the kidneys of a kind as described was not detected in the remaining animals of this dose group. Likewise a deposition of the dye in the tissue of the testes was not detected.

Based on all findings the ‘No observed effect level’ (NOEL) was conservatively placed at 1000 mg/kg body weight/day for male and 250 mg/body weight/day for female animals.

Evaluation and Assessment

Based on all available data, Reaktiv Rot F‑66813 does not exhibit a conspicuous toxicokinetic behaviour. The data of the acute dermal toxicity and dermal irritation test indicate low dermal permeability, owing to the fact that neither systemic nor relevant irritating effects were observed. This is in accordance with the physico-chemical properties of Reaktiv Rot F‑66813. Oral resorption of Reaktiv Rot F‑66813 is probably also restricted due to the low log Kow of -3 since most substances with a log Kow < 0.5 are only marginally resorbed. However, taking the results of the subacute oral toxicity study into account, Reaktiv Rot F‑66813 seems to be absorbed from the gastrointestinal tract to some extent as indicated by discoloration of the urine and inner organs. Reddish discoloured faeces after oral administration of Reaktiv Rot F‑66813 indicated that the compound is predominantly eliminated via intestine. This corresponds to the fact that substances with a molecular weight above 300 g/mol are preferentially excreted via the faeces in rats. Discoloured urine however showed that the test compound is at least partly eliminated via kidneys/urine, too. Taking the hydrophilic nature as well as the log Kow of Reaktiv Rot F‑66813 into account a significant bioaccumulation potential can most probably be excluded. Additionally, Reaktiv Rot F‑66813 was also not mutagenic in the Ames test as well as in in the in vivo micronucleus test. Therefore, a metabolisation towards genotoxic structures 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 Reaktiv Rot F‑66813. The data indicate that there is little or no dermal absorption. No signs of a significant systemic absorption potential have been observed. A bioaccumulation of Reaktiv Rot F66813 can most probably be excluded due to the marked hydrophilic properties. Based on the results of all mutagenicity assays, a metabolisation towards genotoxic sub-structures can most probably be ruled out.