Disodium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate

Endpoint summary

Description of key information

Skin sensitization study ofsubstanceD & C Red No. 6 (CAS no: 5858-81-1) was conductedto determine the allergic contact dermatitis caused by the chemical via performing patch test on human patients. The dye was applied on15patients in Finn Chambers and read first at 2 or (more commonly) 3 days and again at 4–7 days. The reactions of the patients were graded as ‘?+ ‘ , ‘+’ and ‘++’ categories. None of the treated patients showedany signs ofallergic contact dermatitis. Hencethe chemical D & C Red No. 6 (CAS no: 5858-81-1) can be considered as non sensitizer to human skin.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Various studies has been investigated for the test chemical D & C Red No. 6 (CAS no: 5858-81-1)to observe the potential for skin sensitization to a greater or lesser extent. The studies are based on in vivo experiments in guinea pigs, mouse and humans for target chemicalD & C Red No. 6 (CAS no: 5858-81-1)and its structurally similar read across substanceD&C Red 36(CAS no: 2814-77-9)which are summarized as follows;

 

The Guin JD. (2003) conducted skin sensitization studyfortest substanceD & C Red No. 6 (CAS no: 5858-81-1)to determine the allergic contact dermatitis caused by the chemical via performing patch test on human patients. The dye was applied on15patients in Finn Chambers and read first at 2 or (more commonly) 3 days and again at 4–7 days. The reactions of the patients were graded as ‘?+ ‘ , ‘+’ and ‘++’ categories. None of the treated patients showedany signs ofallergic contact dermatitis. Hencethe chemical D & C Red No. 6 (CAS no: 5858-81-1) can be considered as non sensitizer to human skin.

 

The Bibra toxicology advice & consulting (1993) andIFA GESTIS (2017) reported apatch testof test chemicalD & C Red No. 6 (CAS no: 5858-81-1)in probands (man) to assess its skin sensitization potential.Each subject was patch tested with aqueousD & C Red No. 6suspension on their skins within the framework of repeated 48-hour patch under occlusive conditions. After 5 weeks of rest period, subjects were challenged and later observed for any sign of contact sensitization. Approx. one third o f the probands who had undergone the application showed positive reactions. Thus the chemical D & C Red No. 6 (CAS no: 5858-81-1) can be considered as skin sensitizing to the human skin.

 

Anotherskin sensitization study of chemicalD & C Red No. 6 (CAS no: 5858-81-1)was conducted in guinea pigs byIFA GESTIS (2017)to assess its skin sensitization potential.The chemicalD & C Red No. 6 (CAS no: 5858-81-1) failed to induce skin sensitization in treated guinea pigs. Hence chemical D & C Red No. 6 (CAS no: 5858-81-1) can be considered as not skin sensitizing to the guinea pigs’ skin as no known signs of contact sensitization were observed.

 

THE SCIENTIFIC COMMITTEE ON COSMETIC PRODUCTS AND NON-FOOD PRODUCTS (SCCNFP, 2004) conductedtheLocal Lymph Node Assay (LLNA)of test chemicalD & C Red No. 6 (CAS no: 5858-81-1)in CBA/J mice by measuring the cell proliferation in the draining lymph nodes after topical application onto the ears.About 25 μl of 0 (vehicle only), 0.5, 1, 2 and 4 % (exceeding the maximal solubility for both vehicles used) of Pigment Red 57 in either DMSO or a mixture of water/acetone (1:1) with olive oil (4:1) were applied for three consecutive days to the surface of the ear of 5 female CBA/J mice per group. After application, the ears were dried for about 5 minutes by means of a hair dryer. A positive control (p-phenylenediamine at 1 % in DMSO) was investigated in parallel under identical tests conditions. At day 5 the mice received an intravenous injection of 250 μl phosphate buffered saline containing 21.4 μCi of [H3] methyl thymidine. About five hours later the mice were sacrificed by CO2-inhalation and the draining auricular lymph node was removed and weighed. After preparing a single cell suspension from the lymph nodes of each mouse, cells were precipitated by TCA and the radioactivity due to incorporation of [H3] methyl thymidine in the pellets was determined by liquid scintillation counting as disintegration per minute (dpm).Animals were checked twice daily for morbidity/mortality. Observation for clinical signs was done daily before and at least once after dosing. Bodyweight was determined at day – 1 and day 5. With the test item in DMSO mean stimulation indices of 1.2, 1.1, 1.0 and 1.2 were obtained for the 4 test concentrations of 0.5, 1, 2 and 4 %, respectively. In the second vehicle (water/acetone/olive oil) the indices were 1.0, 0.8, 1.2 and 1.6 for the 4 test concentrations. The positive control (PPD, 1% in DMSO) caused an increase in the stimulation index by a factor of 7.8 and an increase of the mean lymph nodes weight by a factor of 1.8 and demonstrated the sensitivity and validity of the system used.Pigment Red 57 did not reveal any potential to be a skin sensitizer. Neither clinical signs nor mortalities were observed throughout the study period. The body weight development was not affected by the treatment. The weight of lymph nodes did not increase compared to the vehicle controls.Based on the findings, the chemical D & C Red No. 6 (CAS no: 5858-81-1) can be considered as non skin sensitizing in the local lymph node assay.

 

The above results are further supported by the experimental study conducted by Guin JD. (2003)forstructurally similar read across substanceD&C Red 36(CAS no: 2814-77-9)to determine the allergic contact dermatitis caused by the chemical via performing patch test on human patients. The dye was applied on14patients in Finn Chambers and read first at 2 or (more commonly) 3 days and again at 4–7 days. The reactions of the patients were graded as ‘?+ ‘ , ‘+’ and ‘++’ categories. None of the treated patients showedany signs ofallergic contact dermatitis. Hencethe chemicalD&C Red 36(CAS no: 2814-77-9) can be considered as non sensitizer to human skin.

 

Although the positive result was observed in man but the potential of causing contact sensitivity was low also only one third of the total subjects showed skin effects. Thus on the basis of the available data for the target and read across substances and applying the weight of evidence approach, D & C Red No. 6 (CAS no: 5858-81-1) can be considered to be not sensitizing to the skin. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The skin sensitization potential of test substance D & C Red No. 6 (CAS no: 5858-81-1) and its structurally similar read across substanceD&C Red 36(CAS no: 2814-77-9) were observed in various studies. From the results obtained from these studies it is concluded that the chemical D & C Red No. 6 (CAS no: 5858-81-1) is not able to cause skin sensitization and hence can be classified under the category “Not Classified” as per CLP regulation.