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Reference
Endpoint:
basic toxicokinetics, other
Type of information:
other: expert statement
Remarks:
Evaluation of availible toxicity studies
Adequacy of study:
other information
Conclusions:
Based on the available database on C.I. Pigment Yellow 214 relevant information exists to make a qualitative evaluation of the toxico-kinetic profile of this compound. This is in line with animal welfare considerations because additional animal tests can be avoided by such an evaluation.

The results of basic toxicity testing give no reason to anticipate unusual characteristics with regard to the toxico-kinetics of C.I. Pigment Yellow 214. The data indicate that there is no relevant dermal absorption. C.I. Pigment Yellow 214 is not absorbed from the gastro-intestinal tract in toxicologically significant amounts. Indications of a bio-accumulative po-tential as well as metabolism towards genotoxic sub-structures do not exist. Excretion of small amounts of possibly systemically available C.I. Pigment Yellow 214 and/or metabolites via faeces is likely.
Executive summary:

Introduction:

Toxicokinetic parameters such as uptake, distribution, metabolism and excretion form part of the essential toxicological profile of a substance. Although the toxicokinetic behaviour of substances does not describe a toxicological endpoint itself, an approximate indication of the individual toxicokinetic parameters absorption, distribution, metabolism and excretion (ADME) can be gained from the results of basic toxicity testing. In this respect, the following evaluation discusses results and observations from basic toxicity studies, which can be used as approximate indications for the description of individual toxicokinetic parameters. Such an approach is justified by animal welfare considerations because additional animal testing can be avoided. The assessment of the toxicokinetic properties of C.I. Pigment Yellow 214 given below is based on the results obtained for the following toxicological endpoints:

        ·               Acute oral toxicity

·               Skin irritation

·               Eye Irritation

·               Skin sensitisation

·               Ames-test

·               In vitro cytogenetic assay

·               Subacute oral toxicity (OECD 407)

  

All of these studies were carried out according to the principles of Good Laboratory Practice and met the requirements of the OECD and EU-Guidelines for the Testing of Chemicals. Simultaneously physico-chemical data such as solubility, log Powand hydrolytic stability are considered in the evaluation. This information gives additional indications regarding special toxicokinetic parameters, e.g. distribution, metabolism and excretion.

 

Substance Identity:

C.I. Pigment Yellow 214 is the Color Index name for 3,3'-((2-Chlorophen-1,4-ylene)bis((1,3-dioxobutane-1,2-diyl) imino)azo)-4-methylbenzamide (CAS: 253430-12-5). The purity of C.I. Pigment Yellow 214 was ca. 99% and the material was available as a yellow powder.

 

Toxicological Profile:

C.I. Pigment Yellow 214 was tested for acute oral toxicity in female rats. After application of 2000 mg/kg body weight by gavage no dose-related adverse effectswere observed.Body weight development was not influenced. Macroscopically visible changes were not observed. Based on these results the median lethal dose (oral, LD50) of the test material in the rat is greater than2000 mg/kg body weight.

The test material is not irritating to the skin and is not irritating to eyes.

Testing for sensitizing properties in guinea pigs using the Maximisation test revealed that C.I. Pigment Yellow 214 is a no skin sensitizer.

C.I. Pigment Yellow 214 gave negative results in Ames tests with S. typhimurium as well as E. coli with and without metabolic activation.

The test item did not cause chromosomal aberrations in Chinese hamster fibroblast in vitro with and without metabolic activation.

 

Based on the results of a sub-acute oral toxicity study (OECD 407) with C.I. Pigment Yellow 214, daily administration of doses of 0, 50, 200 and 1000 mg/kg body weight to rats has not caused compound-related toxicity.The general health status of the animals was not altered.The only finding relevant for the assessment of ADME was an yellow discoloration of faeces at necropsy indicating direct excretion of the material.A `No Observed Adverse Effect Level` (NOAEL) of 1000 mg test material per kg body weight per day was established.

 

Evaluation and Assessment of the Toxico-kinetic Profile:

Considering all available toxicological tests, qualitative estimates for ADME-parameters are possible.

Absorption:

A prerequisite for a relevant absorption is that the substance can be dissolved in either aqueous (e.g., gastrointestinal fluid, blood plasma, sweat) or lipophilic (e.g., lipoproteins, lipid membranes, triglycerides) media or in both. Pigment Yellow 214 can be considered insoluble because it has an extremely low solubility in water and n-octanol. Therefore, it is unlikely that Pigment Yellow 214 becomes systemically bioavailable after oral, dermal or inhalation exposure.

Based on the sub-acute oral toxicity study absorption of toxicologically significant amounts of C.I. Pigment Yellow 214 via the gastrointestinal tract is considered unlikely, since it did not show any effects on inner organs, blood or urine.

The skin sensitisation studies indicate no local dermal bioavailability. Systemic availability also seems to be negligible after dermal exposure since no systemic signs of intoxication were seen after occlusive administration of 500 mg C.I. Pigment Yellow 214 per kg body weight in rabbits in the acute dermal irritation study.

Dermal absorption, therefore, is considered unlikely

In the unlikely event of exposure to aerosolized pigment in respirable form, the substance is considered to behave like an inert dust. Therefore, the deposited pigment particles will mostly be cleared from the lung via the mucociliary transport. As the pigment will not dissolve in the lung surfactant, the only way the pigment can enter the body is via phagocytosis of pigment particles by lung macrophages followed by migration of the macrophages into the interstitium and into the draining lymph nodes. However, the internal dose delivered via this mechanism is considered negligible.

 

Distribution:

The Repeated Dose Toxicity Study did not indicate any relevant histopathological changes in any of the investigated organs. This may indicate that the pigment either does not affect special organs as targets, i.e., is non-toxic, or is not distributed within the body in significant amounts. As indicated above, the physico-chemical parameters of the pigment support the conclusion that the pigment is not absorbed into the body and thus does not become systemically available. There were also no other signs of deposition of the pigment in any organ including excretory organs, like the kidney, indicating that even exposure to high doses of the pigment does not lead to bioaccumulation in special compartments of the body.

Based on the available information on absorption distribution of the test material in the body in significant amounts is unlikely and specific hotspots of distribution cannot be identified.

Thus it is concluded, that C.I. Pigment Yellow 214 is not systemically available at relevant concentrations within the organism.

There were no signs of bioaccumulation of the test material. This view is supported by the physical-chemical properties (solubility in water).

 

Metabolism:

Since the solution of the substance in cellular fluid or cellular membranes is a prerequisite for its metabolism, it is unlikely that the insoluble pigment becomes accessible for metabolizing systems in relevant amounts.

The results of the mutagenicity tests provide useful indications for qualitative consideration of the metabolic fate of Pigment Yellow 214. In the mutagenicity tests, the pigments proved to be non-mutagenic in the absence as well as in the presence of an exogenous metabolizing system, indicating that the pigment is not converted into toxic or genotoxic metabolites.This conclusion is also supported by the lack of any morphological and histopathological changes of organs involved in xenobiotic metabolism, such as the liver, in the Repeated Dose Toxicity Study. Furthermore, the missing skin or eye irritating or skin sensitizing properties argue against any interaction with biological material.

Therefore, C.I. Pigment Yellow 214 is considered to just pass through the intestinal tract without significant metabolism.

 

Excretion:

Taking into account the physico-chemical properties and the molecular structure of the material and the absence of any indication of absorption and/or metabolism it is assumed that excretion, if any, is likely to occur via faeces. This notion is confirmed by the discoloration of faeces observed in the subacute study as the only alteration.

 

Conclusion:

Based on all available data, C.I. Pigment Yellow 214 does not exhibit conspicuous toxico-kinetic behaviour in the sense of accumulative and/or delayed effects with regard to the individual parameters absorption, distribution, metabolism and excretion.

The results from studies with dermal exposure indicate that C.I. Pigment Yellow 214 has a no relevant dermal absorptive potential. C.I. Pigment Yellow 214 is most probably not absorbed from the gastrointestinal tract in significant amounts.

Indications of an intense metabolism or a bio-accumulative potential do not exist as no toxicity occurred.Additionally, no systemic effects were observed in the subacute oral toxicity study, which points to no bio-accumulation potential and complete excretion of all available C.I. Pigment Yellow 214 and/or possible metabolites.

Description of key information

Based on the available database on C.I. Pigment Yellow 214 relevant information exists to make a qualitative evaluation of the toxico-kinetic profile of this compound. This is in line with animal welfare considerations because additional animal tests can be avoided by such an evaluation.

The results of basic toxicity testing give no reason to anticipate unusual characteristics with regard to the toxico-kinetics of C.I. Pigment Yellow 214. The data indicate that there is no  relevant dermal absorption. C.I. Pigment Yellow 214 is not absorbed from the gastro-intestinal tract in toxicologically significant amounts. Indications of a bio-accumulative po-tential as well as metabolism towards genotoxic sub-structures do not exist. Excretion of small amounts of possibly systemically available C.I. Pigment Yellow 214 and/or metabolites via faeces is likely.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information