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Description of key information

The skin sensitization potential of target chemical hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) was assessedin various experimental studies which were conducted on guinea pigs and humans for target chemicalhexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) andits structurally similar read across substances2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[2-[4 -[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, sodium salt (1:4) (Reactive Red 198) [CAS: 145017-98-7] and disodium 2,2'-ethene-1,2-diylbis{5-[(4-anilino-6-morpholin-4-yl-1,3,5-triazin-2-yl)amino]benzenesulfonate}) (CAS No: 16090-02-1). The predicted data usingQSAR toolboxhas also been compared with the experimental data.Based on the available data for the target and read across substances and applying the weight of evidence approach, it can be concluded that chemical hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) is unable to cause skin sensitization and thus can be considered as not sensitizing. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Justification for type of information:
Data is from OECD QSAR toolbox version 3.4 and QMRF report has been attached
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: estimated data
Principles of method if other than guideline:
Prediction is done using QSAR Toolbox version 3.4
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- IUPAC Name: hexasodium 4,4'-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate}
- SMILES:CCN1C(O)=C(N=Nc2cc(Nc3nc(Nc4ccc(C=Cc5ccc(Nc6nc(Nc7cc(N=NC8=C(O)N(CC)C(=O)C(C(N)=O)=C8C)c(S(O)(=O)=O)cc7S(O)(=O)=O)nc(Cl)n6)cc5S(O)(=O)=O) c(S(O)(=O)=O)c4)nc(Cl)n3)c(S(O)(=O)=O)cc2S(O)(=O)=O)C(C)=C(C(N)=O)C1=O
- InChI:1S/C50H44Cl2N18O24S6/c1-5-69-41(73)35(39(53)71)19(3)37(43(69)75)67-65-27-15-25(31(97(83,84)85)17-33(27)99(89,90)91)57-49-61-45(51)59-47(63-49)55-23-11-9-21 (29(13-23)95(77,78)79)7-8-22-10-12-24(14-30(22)96(80,81)82)56-48-60-46(52)62-50(64-48)58-26-16-28(34(100(92,93)94)18-32(26)98(86,87)88)66-68-38-20(4)36(40(54)72)42(74)70(6-2)44(38)76/h7-18,75-76H,5-6H2,1-4H3,(H2,53,71)(H2,54,72)(H,77,78,79)(H,80,81,82)(H,83,84,85)(H,86,87,88)(H,89,90,91)(H,92,93,94)(H2,55,57,59,61,63)(H2,56,58,60,62,64)/b8-7?,67-65+,68-66+
- Molecular Formula: C50H44Cl2N18O24S6.6Na
- Molecular Weight: 1544.3016 g/mole
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
not specified
Details on test animals and environmental conditions:
No data available
Route:
intradermal and epicutaneous
Vehicle:
not specified
Concentration / amount:
No data available
Day(s)/duration:
No data available
Adequacy of induction:
not specified
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
not specified
Concentration / amount:
No data available
Day(s)/duration:
48 hours
Adequacy of challenge:
not specified
No. of animals per dose:
20
Details on study design:
No data available
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
No data available
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No skin sensitization was observed in treated group.
Remarks on result:
no indication of skin sensitisation
Cellular proliferation data / Observations:
No skin sensitization was observed in treated group.

The prediction was based on dataset comprised from the following descriptors: "Skin Sensitisation"
Estimation method: Takes highest mode value from the 6 nearest neighbours
Domain  logical expression:Result: In Domain

(((((((("a" or "b" or "c" or "d" )  and ("e" and ( not "f") )  )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and ( not "p") )  )  and ("q" and "r" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Iminium Ion Formation AND SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines by DNA binding by OECD

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Nucleophilic addition AND Nucleophilic addition >> Addition to carbon-hetero double bonds AND Nucleophilic addition >> Addition to carbon-hetero double bonds >> Ketones AND SNAr AND SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds AND SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds >> Activated aryl and heteroaryl compounds by Protein binding by OASIS v1.4

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Direct Acylation Involving a Leaving group AND Acylation >> Direct Acylation Involving a Leaving group >> Acetates AND SNAr AND SNAr >> Nucleophilic aromatic substitution AND SNAr >> Nucleophilic aromatic substitution >> Halo-triazines by Protein binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acid moiety AND Acrylamides AND Triazines, Aromatic AND Vinyl/Allyl Alcohols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.4

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation >> Geminal Polyhaloalkane Derivatives OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide and Aminoalkylamine Side Chain OR Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Geminal Polyhaloalkane Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> N,N-Dialkyldithiocarbamate Derivatives OR SN1 OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Acylation involving a leaving group after metabolic activation OR SN2 >> Acylation involving a leaving group after metabolic activation >> Geminal Polyhaloalkane Derivatives OR SN2 >> Alkylation, direct acting epoxides and related OR SN2 >> Alkylation, direct acting epoxides and related >> Epoxides and Aziridines OR SN2 >> Direct acylation involving a leaving group OR SN2 >> Direct acylation involving a leaving group >> Acyl Halides OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation >> Geminal Polyhaloalkane Derivatives by DNA binding by OASIS v.1.4

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Iminium Ion Formation AND SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines by DNA binding by OECD

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems >> Thiophenes-Michael addition OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Arenes OR Michael addition >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated amides OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR No alert found OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Aromatic phenylureas OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine OR SN2 OR SN2 >> P450 Mediated Epoxidation OR SN2 >> P450 Mediated Epoxidation >> Thiophenes-SN2 by DNA binding by OECD

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Non binder, MW>500 by Estrogen Receptor Binding

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Non binder, impaired OH or NH2 group OR Non binder, non cyclic structure OR Non binder, without OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as alpha,beta-unsaturated carbonyls AND H-acceptor-path3-H-acceptor by in vivo mutagenicity (Micronucleus) alerts by ISS

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Alkyl carbamate and thiocarbamate by in vivo mutagenicity (Micronucleus) alerts by ISS

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Halogens AND Non-Metals by Groups of elements

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Alkali Earth by Groups of elements

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Group 14 - Carbon C AND Group 15 - Nitrogen N AND Group 16 - Oxygen O AND Group 16 - Sulfur S AND Group 17 - Halogens Cl AND Group 17 - Halogens F,Cl,Br,I,At by Chemical elements

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Group 15 - Phosphorus P by Chemical elements

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of log Kow which is >= 0.405

Domain logical expression index: "r"

Parametric boundary:The target chemical should have a value of log Kow which is <= 15.2

Interpretation of results:
other: Not sensitizing
Conclusions:
The chemical hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) was estimated to be not sensitizing to the Dunkin-Hartley guinea pigs. Based on the estimated result hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) failed to induce skin sanitization effects and hence is considered to be not sensitizing to Dunkin-Hartley guinea pigs.
Executive summary:

The skin sensitization potential of hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) was estimated using OECD QSAR toolbox version 3.4 with log Pow as the primary descriptor. The chemical hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) was estimated to be not sensitizing to the Dunkin-Hartley guinea pigs. Based on the estimated result hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) failed to induce skin sanitization effects and hence is considered to be not sensitizing to Dunkin-Hartley guinea pigs and can be classified under the category ˋ Not Classified’ as per CLP regulation. 

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Various studieshas been investigated for the test chemicalhexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0)  to observe the potential for skin sensitization to a greater or lesser extent. The studies are based on in vivo experiments in guinea pigs for target chemicalhexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0)  and its structurally similar read across substances2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[2-[4 -[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, sodium salt (1:4) (Reactive Red 198) [CAS: 145017-98-7] and disodium 2,2'-ethene-1,2-diylbis{5-[(4-anilino-6-morpholin-4-yl-1,3,5-triazin-2-yl)amino]benzenesulfonate}) (CAS No: 16090-02-1).The predicted data using the OECD QSAR toolbox has also been compared with the experimental data and summarized as below;

 

 

The skin sensitization potential of hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0)  was estimated by SSS (2017) using OECD QSAR toolbox v3.3 with log kow as the primary descriptor. The substance hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0)  failed to induce skin sanitization effects on guinea pig skin and hence is considered to be not sensitizing to the skin.

 

This was supported by the results of the Patch tests performed by Bianca Maria Manzini et.al (Contact Dermatitis, 1996, 35, 313) on 312 consecutive patients to determine the allergic potential of read across chemical, , 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[2-[4 -[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, sodium salt (1:4) (Reactive Red 198) [CAS: 145017-98-7]. 312 consecutive patients underwent patch tests with reactive dyes to determine the allergic contact dermatitis potential. The dyes tested were provided as powder by Hoechst and were dispersed in petrolatum. The dyes were applied to the healthy sin of the back with Finn Chambers, on Scanpor tape for 3 days and read at 3 hours after removal and at 4 days according to ICDRG Scoring pattern. The concentration used was 5% in 119 patients and 10% in 193 patients. No positive allergic or irritant reactions were observed in the volunteers when tested with 5% and 10% concentration of the dye. Hence, Reactive Red 198 can be considered to not sensitizing to human skin.

 

The above results were further supported by the maximization test reported by OECD SIDS {SIDS Initial Assessment Report For SIAM 21- FLUORESCENT BRIGHTENER FWA-1; Washington, D.C; U.S.A., 18-20 October 2005} in rabbits for read across chemical disodium 2,2'-ethene-1,2-diylbis{5-[(4-anilino-6-morpholin-4-yl-1,3,5-triazin-2-yl)amino]benzenesulfonate}) (CAS No: 16090-02-1) on female Himalayan spotted albino Guinea pigs in accordance with OECD TG 406 . Induction was performed by intradermal injections and later by topical application in the interscapular region. Intradermal induction was performed by 3 pairs of intradermal injections in the interscapular region of the animals (0.1 ml/site): 1) a 1 : 1 mixture of Freund’s Complete adjuvant (FCA) with physiological saline, 2) a 1 % dilution of the test item in physiological saline and 3) a 1 % dilution of the test item in an 1 : 1 mixture of FCA and physiological saline. A control group was treated accordingly without the test item. On day 7, test sites were pretreated with 10 % sodium lauryl sulfate (SLS) to enhance sensitization by provoking a mild inflammatory reaction. On day 8, epidermal induction was performed by topical application of the chemical at 25 % in vaseline (nonirritating concentration of test item) for 48 hours under occlusive dressing. After a resting period of 2 weeks, the challenge was performed by epidermal application of the chemical at 25 % in vaseline under occlusive dressing for 18 hours. Cutaneous reactions, e.g. erythema and eschar as well as edema formation, were evaluated at 24 and 48 hours after the removal of the dressing. No clinical signs of systemic toxicity or dermal effects were noted in the treated animals and no deaths occurred. Both, 24 and 48 hours after challenge application, all skin reaction scores for erythema and edema were zero in each of the control and treated animals. Therefore the chemical disodium 2,2'-ethene-1,2-diylbis{5-[(4-anilino-6-morpholin-4-yl-1,3,5-triazin-2-yl)amino]benzenesulfonate}) (CAS No: 16090-02-1) was considered to be not sensitizing on female Himalayan spotted albino Guinea pigs.

 

 

Based on the available data for thetargethexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0)  and its structurally similar read across substances2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[2-[4 -[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, sodium salt (1:4) (Reactive Red 198) [CAS: 145017-98-7] and disodium 2,2'-ethene-1,2-diylbis{5-[(4-anilino-6-morpholin-4-yl-1,3,5-triazin-2-yl)amino]benzenesulfonate}) (CAS No: 16090-02-1),it can be concluded thatchemical hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0) is unable to cause skin sensitization and considered as non-skin sensitizer.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The skin sensitization potential of test substance hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0)  and its structurally similar read across substances2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[2-[4 -[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, sodium salt (1:4) (Reactive Red 198) [CAS: 145017-98-7] and disodium 2,2'-ethene-1,2-diylbis{5-[(4-anilino-6-morpholin-4-yl-1,3,5-triazin-2-yl)amino]benzenesulfonate}) (CAS No: 16090-02-1) were observed in various studies. From the results obtained from these studies it is concluded that the chemical hexasodium 4,4’-{ethene-1,2-diylbis[(3-sulfonato-4,1-phenylene)imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]}bis{6-[(5-carbamoyl-1-ethyl-2-hydroxy-4-methyl-6-oxo- 1,6-dihydropyridin-3-yl)diazenyl]benzene-1,3-disulfonate} (CAS No: 68991-98-0)  is not likely to cause skin sensitization and hence can be classified as non-skin sensitizer.