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Description of key information

The results of basic toxicity testing give no reason to anticipate unusual characteristics with regard to the toxicokinetics of Reactive Red 239

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information


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 Reactive Red 239 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

  • Subacute (28-day) oral toxicity in rats

  • Subchronic (90-day) oral toxicity study in rats

All studieswere 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

Name:                      Reactive Red 239/Reactive Red F-52 167 FW

CAS number:             89157-03-9

CAS name:                1,5-Naphthalenedisulfonic acid, 2-[2-[8-[[4-chloro-6-[[4-[[2-(sulfooxy)ethyl] sulfonyl]phenyl]amino]-1,3,5-triazin-2-yl]amino]-1-hydroxy-3,6-disulfo-2-naphthalenyl]diazenyl]-, sodium salt (1:5)

Physical state:            solid, red odourless powder

Empirical formula:      C31H19ClN7Na5O19S6

Molecular weight:       1136.3g/mol                               (>500 daltons =bad absorption)

Water solubility:         299 g/L                                           (= soluble in water)

Partition coefficient:    log Kow< -2                               (<-0.4 or >5.6 =bad absorption)

Surface tension:         55.6 mN/m                                   (<60 = surface active)

Vapor pressure:          NA                                                  (not volatile)

Atom count (natoms):  64                                                     (<70 =good bioavailability)

H-bond acceptor (nON): 26                                                     (>10 =bad bioavailability)

H-bond donor (nOHNH):  3          (<5 =good bioavailability)

Toxicological Profile

After single oral administration of Reactive Red 239 at a dose level of 5000 mg/kg body weight to male and female rats no deaths or clinical signs other than unspecific signs of toxicity occurred. Similarly, single dermal application of 2000 mg/kg body weight onto male and female rats produced no deaths or signs of systemic toxicity. The median lethal dose (LD50) of Reactive Red 239 after oral and dermal administration to rats is greater than 5000 and 2000 mg/kg body weight, respectively.

Testing for skin irritating properties of Reactive Red 239 in rabbits led to a minimal erythema up to 48 hours after test item administration. The administration of Reactive Red 239 into the conjunctival sac of rabbit eyes did not result in significant irritation of the conjunctiva. Consequently, Reactive Red 239 is not irritating to skin or eyes according to the classification criteria of Directive 2001/59/EC or Regulation (EC) No 1272/2008.

Testing for sensitizing properties of Reactive Red 239 was performed in the guinea pig maximisation Assay. No evidence of skin sensitizing properties was found.


The effects of Reactive Red 239 during repeated administration were tested  in oral gavage studies in rats over periods of 30 and 90 days. The recovery (treatment free) periods in these studies, were 2 and 4 weeks, respectively. No toxicological relevant effects were seen in these studies. Pink to dark pink discolourations were found in blood serum, urine and several organs and tissues. Kidneys showed a deposition of the test item in vacuoles in the tubular cells of the cortex. All of these effects were reversible.

Reactive Red 239 was tested for bacterial mutagenicity in two independent tests including the Prival modification for azo-compounds in the presence and absence of metabolic activation systems from rat and hamster liver. The test compound did not cause a significant increase in the number of revertant colonies with any of the tester strains either in the absence or in the presence of S9-mix in either of these tests.

Reactive Red 239 has been assessed for its clastogenic and aneugenic potential in an in vivo Micronucleus Assay in the mouse at a dose level of 6250 mg/kg bw. Due to the colour of the test compound urine, faeces and skin were red coloured, which proved sufficient exposure to Reactive Red 239 and/or its metabolites. No induction of micronuclei in bone marrow erythrocytes was observed, thus, there was no evidence of any genotoxic activity of the test item.

Evaluation and Assessment

Based on all available data, Reactive Red 239 does not exhibit a conspicuous toxicokinetic behaviour.

Reactive Red 239 is a dark red powdered solid at room temperature conditions. The degree of purity of the substance is 45 - 75%. The melting point of the substance is >320°C therefore a significant inhalation exposure to vapours is not expected. In view of the low n-octanol/water partition coefficient (log Kow <– 2 at 20°C), systemic bioavailability after dermal exposure is not anticipated.

Reactive Red 239 has a very low acute toxicity potential. The data of the acute dermal toxicity, dermal irritation test and skin sensitization testing indicate low dermal permeability, owing to the fact that neither systemic nor irritating or sensitizing effects were observed. This is in accordance with the extremely good solubility of the test substance in water and with the molecular weight and number of H-bond acceptors, giving evidence of a poor systemic bioavailability.

According to its atom count and H-bond donors, Reactive Red 239 should be absorbed from the gastrointestinal tract to some extent, whereas the molecular weight, log Kow and number of H-bond acceptors indicate a low absorption of the test substance. Taking the results of the subacute and subchronic oral toxicity studies into account, Reactive Red 239 is absorbed from the gastrointestinal tract and is systemically available to some extent, as proven by the staining of inner organs, serum and urine, the latter serving as an indication of the bioelimination of absorbed Reactive Red 239 or its metabolites. The discolorations seen, were related to the tinctorial properties of the test substance (dye-stuff), but do not represent a toxicologically relevant finding. The reversibility of the discolourations is a good indicator that the test substance does not have bioaccumulative properties. According to the molecular weight, excretion of Reactive Red 239 is most likely predominantly eliminated via intestine, as substances with a molecular weight above 300 g/mol are preferentially excreted via the faeces in rats. However, the test results showed that the test compound is at least partly eliminated via kidneys/urine, too.

Due to its high water solubility and low log Kow, Reactive Red 239 is not bioaccumulative. This is confirmed by the results of repeat dose studies and of the bioaccumulation modelling, excluding a significant bioaccumulation potential of Reactive Red 239. Additionally, Reactive Red 239 was also not genotoxic in an in-vitro cell mutagenicity test and an in-vivo MNT test. Therefore, a metabolisation towards genotoxic structures by mammalian species can most probably be excluded.


The results of basic toxicity testing give no reason to anticipate unusual characteristics with regards to the toxicokinetics of Reactive Red 239. The data indicate that there is little or no dermal absorption. No signs of a significant systemic toxicity associated with absorption potential have been observed. Bioaccumulation of Reactive Red 239 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.

On the basis of the results, it is anticipated that the substance does not undergo significant metabolic activity; rather it is metabolized for excretion with little subsequent toxicity. The substance is therefore not considered to be of concern for ADME related effects.