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EC number: 229-043-5 | CAS number: 6407-78-9
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
Skin irritation
The dermal irritation potential of target chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was assessedin various experimental studies which were conducted on rabbits for target chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) and its functionally similar read across substancesC.I. Pigment Red 3 (CAS No: 2425-85-6)andSodium 4-(3-hydroxy-5-methyl-4-phenylazopyrazol-2-yl)benzenesulphonate(CAS No:6359-82-6). 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 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) is unable to cause skin irritation and thus considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.
Eye irritation
An ocular irritation potential of target chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was assessedin various experimental studies which were conducted on rabbits for target chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) and its structurally similar read across substanceEdaravone(CAS No:-89-25-8) and functionally similar read across substance C.I. Pigment Red 3(CAS No: 2425-85-6). 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 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) is unable to cause eye damage and thus can be considered as not irritating. 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 irritation / corrosion
Link to relevant study records
- Endpoint:
- skin irritation: in vivo
- 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 3.3 and QMRF report has been attached
- Qualifier:
- according to guideline
- Guideline:
- other: estimated data
- Principles of method if other than guideline:
- Prediction is done using QSAR Toolbox version 3.3
- GLP compliance:
- not specified
- Specific details on test material used for the study:
- - Name of test material (IUPAC name): 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one
- Common name: Solvent Yellow 18
- Molecular formula: C18H18N4O
- Molecular weight: 306.367 g/mol
- Smiles notation: O=C1N(N=C(C)[C@@H]1\N=N\c1c(cc(cc1)C)C)c1ccccc1
- InChl: 1S/C18H18N4O/c1-12-9-10-16(13(2)11-12)19-20-17-14(3)21-22(18(17)23)15-7-5-4-6-8-15/h4-11,17H,1-3H3/b20-19+
- Substance type: Organic
- Physical state: Solid - Species:
- rabbit
- Strain:
- New Zealand White
- Details on test animals or test system and environmental conditions:
- No data available
- Type of coverage:
- occlusive
- Preparation of test site:
- clipped
- Vehicle:
- not specified
- Controls:
- not specified
- Amount / concentration applied:
- No data available
- Duration of treatment / exposure:
- 24 hours
- Observation period:
- 72 hours
- Number of animals:
- 3
- Details on study design:
- No data available
- Irritation parameter:
- overall irritation score
- Basis:
- mean
- Time point:
- 72 h
- Reversibility:
- not specified
- Remarks on result:
- no indication of irritation
- Irritant / corrosive response data:
- No skin irritation was observed.
- Interpretation of results:
- other: not irritating
- Conclusions:
- The chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was estimated to be not irritating to the skin of New Zealand White rabbits. Based on the estimated result 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) can be considered to be not irritating to skin.
- Executive summary:
The dermal irritation potential of 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was estimated using OECD QSAR toolbox version 3.4 with logPow as the primary descriptor. The chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was estimated to be not irritating to the skin of New Zealand White rabbits. Based on the estimated result 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) can be considered to be not irritating to skin and can be classified under the category ˋ Not Classified’ as per CLP regulation.
Reference
Estimation
method: Takes mode value from the 5 nearest neighbours
Domain logical expression:Result: In Domain
((((((("a"
or "b" or "c" or "d" or "e" or "f" or "g" )
and ("h"
and (
not "i")
)
)
and "j" )
and "k" )
and "l" )
and ("m"
and (
not "n")
)
)
and ("o"
and "p" )
)
Domain
logical expression index: "a"
Referential
boundary: The
target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion
formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo AND SN1 >>
Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding
by OECD
Domain
logical expression index: "b"
Referential
boundary: The
target chemical should be classified as Schiff base formation AND Schiff
base formation >> Pyrazolones and Pyrazolidinones derivatives AND Schiff
base formation >> Pyrazolones and Pyrazolidinones derivatives >>
Pyrazolones and Pyrazolidinones by Protein binding by OASIS v1.3
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 SN2 AND SN2 >> SN2
reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom
>> Alkyl diazo by Protein binding by OECD
Domain
logical expression index: "d"
Referential
boundary: The
target chemical should be classified as Amides AND Hydrazines by Aquatic
toxicity classification by ECOSAR
Domain
logical expression index: "e"
Referential
boundary: The
target chemical should be classified as Amides OR Hydrazines by Aquatic
toxicity classification by ECOSAR ONLY
Domain
logical expression index: "f"
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 SN2 AND SN2 >> SN2
reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom
>> Alkyl diazo by Protein binding by OECD
Domain
logical expression index: "g"
Referential
boundary: The
target chemical should be classified as Amides AND Hydrazines by Aquatic
toxicity classification by ECOSAR
Domain
logical expression index: "h"
Referential
boundary: The
target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion
formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo AND SN1 >>
Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding
by OECD
Domain
logical expression index: "i"
Referential
boundary: The
target chemical should be classified as Acylation OR Acylation >> P450
Mediated Activation to Isocyanates or Isothiocyanates OR Acylation >>
P450 Mediated Activation to Isocyanates or Isothiocyanates >> Formamides
OR 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 >> Alkyl phenols OR
Michael addition >> P450 Mediated Activation to Quinones and
Quinone-type Chemicals >> Arenes OR Michael addition >> P450 Mediated
Activation to Quinones and Quinone-type Chemicals >> Hydroquinones OR No
alert found OR SN1 >> Carbenium Ion Formation OR SN1 >> Carbenium Ion
Formation >> Hydrazine OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium
Ion Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion
formation >> Aromatic nitro by DNA binding by OECD
Domain
logical expression index: "j"
Referential
boundary: The
target chemical should be classified as Not bioavailable by Lipinski
Rule Oasis ONLY
Domain
logical expression index: "k"
Similarity
boundary:Target:
Cc1ccc(N=NC2C(C)=NN(c3ccccc3)C2=O)c(C)c1
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization
Domain
logical expression index: "l"
Similarity
boundary:Target:
Cc1ccc(N=NC2C(C)=NN(c3ccccc3)C2=O)c(C)c1
Threshold=50%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization
Domain
logical expression index: "m"
Referential
boundary: The
target chemical should be classified as Not classified by Oncologic
Primary Classification
Domain
logical expression index: "n"
Referential
boundary: The
target chemical should be classified as Aromatic Amine Type Compounds OR
Halogenated Aromatic Hydrocarbon Type Compounds by Oncologic Primary
Classification
Domain
logical expression index: "o"
Parametric
boundary:The
target chemical should have a value of log Kow which is >= 3.34
Domain
logical expression index: "p"
Parametric
boundary:The
target chemical should have a value of log Kow which is <= 8.02
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (not irritating)
Eye irritation
Link to relevant study records
- Endpoint:
- eye irritation: in vivo
- 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 3.3 and QMRF report has been attached
- Qualifier:
- according to guideline
- Guideline:
- other: estimated data
- Principles of method if other than guideline:
- Prediction is done using QSAR Toolbox version 3.3
- GLP compliance:
- not specified
- Specific details on test material used for the study:
- - Name of test material (IUPAC name): 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one
- Common name: Solvent Yellow 18
- Molecular formula: C18H18N4O
- Molecular weight: 306.367 g/mol
- Smiles notation: O=C1N(N=C(C)[C@@H]1\N=N\c1c(cc(cc1)C)C)c1ccccc1
- InChl: 1S/C18H18N4O/c1-12-9-10-16(13(2)11-12)19-20-17-14(3)21-22(18(17)23)15-7-5-4-6-8-15/h4-11,17H,1-3H3/b20-19+
- Substance type: Organic
- Physical state: Solid - Species:
- rabbit
- Strain:
- New Zealand White
- Details on test animals or tissues and environmental conditions:
- No data available
- Vehicle:
- not specified
- Controls:
- not specified
- Amount / concentration applied:
- No data available
- Duration of treatment / exposure:
- single application
- Observation period (in vivo):
- 72 hours
- Number of animals or in vitro replicates:
- 3
- Details on study design:
- No data available
- Irritation parameter:
- overall irritation score
- Basis:
- mean
- Time point:
- 72 h
- Reversibility:
- not specified
- Remarks on result:
- no indication of irritation
- Irritant / corrosive response data:
- No eye irritation was observed in treated rabbits.
- Interpretation of results:
- other: not irritating
- Conclusions:
- The chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was estimated to be not irritating into the eyes of New Zealand White rabbits. Based on the estimated result 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) can be considered to be not irritating to eye.
- Executive summary:
The ocular irritation potential of 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was estimated using OECD QSAR toolbox version 3.4 with logPow as the primary descriptor. The chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) was estimated to be not irritating into the eyes of New Zealand White rabbits. Based on the estimated result 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) can be considered to be not irritating to eye and can be classified under the category ˋ Not Classified’ as per CLP regulation.
Reference
Estimation
method: Takes mode value from the 7 nearest neighbours
Domain logical expression:Result: In Domain
((((("a"
or "b" or "c" or "d" or "e" or "f" or "g" )
and ("h"
and (
not "i")
)
)
and ("j"
and (
not "k")
)
)
and "l" )
and ("m"
and "n" )
)
Domain
logical expression index: "a"
Referential
boundary: The
target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion
formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo AND SN1 >>
Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding
by OECD
Domain
logical expression index: "b"
Referential
boundary: The
target chemical should be classified as Schiff base formation AND Schiff
base formation >> Pyrazolones and Pyrazolidinones derivatives AND Schiff
base formation >> Pyrazolones and Pyrazolidinones derivatives >>
Pyrazolones and Pyrazolidinones by Protein binding by OASIS v1.3
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 SN2 AND SN2 >> SN2
reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom
>> Alkyl diazo by Protein binding by OECD
Domain
logical expression index: "d"
Referential
boundary: The
target chemical should be classified as Amides AND Hydrazines by Aquatic
toxicity classification by ECOSAR
Domain
logical expression index: "e"
Referential
boundary: The
target chemical should be classified as Amides OR Hydrazines by Aquatic
toxicity classification by ECOSAR ONLY
Domain
logical expression index: "f"
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 SN2 AND SN2 >> SN2
reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom
>> Alkyl diazo by Protein binding by OECD
Domain
logical expression index: "g"
Referential
boundary: The
target chemical should be classified as Amides AND Hydrazines by Aquatic
toxicity classification by ECOSAR
Domain
logical expression index: "h"
Referential
boundary: The
target chemical should be classified as No alert found by DNA binding by
OASIS v.1.3
Domain
logical expression index: "i"
Referential
boundary: The
target chemical should be classified as Non-covalent interaction OR
Non-covalent interaction >> DNA intercalation OR Non-covalent
interaction >> DNA intercalation >> DNA Intercalators with Carboxamide
Side Chain OR Non-specific OR Non-specific >> Incorporation into
DNA/RNA, due to structural analogy with nucleoside bases OR
Non-specific >> Incorporation into DNA/RNA, due to structural analogy
with nucleoside bases >> Specific Imine and Thione Derivatives OR
Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR
Radical >> Radical mechanism via ROS formation (indirect) >> Hydrazine
Derivatives OR Radical >> Radical mechanism via ROS formation (indirect)
>> Nitroarenes with Other Active Groups OR Radical >> Radical mechanism
via ROS formation (indirect) >> Specific Imine and Thione Derivatives OR
SN1 OR SN1 >> Nucleophilic attack after diazonium or carbenium ion
formation OR SN1 >> Nucleophilic attack after diazonium or carbenium ion
formation >> Nitroarenes with Other Active Groups OR SN1 >> Nucleophilic
attack after reduction and nitrenium ion formation OR SN1 >>
Nucleophilic attack after reduction and nitrenium ion formation >>
Nitroarenes with Other Active Groups OR SN1 >> Nucleophilic substitution
on diazonium ions OR SN1 >> Nucleophilic substitution on diazonium ions
>> Specific Imine and Thione Derivatives OR SN2 OR SN2 >> SN2 attack on
activated carbon Csp3 or Csp2 OR SN2 >> SN2 attack on activated carbon
Csp3 or Csp2 >> Nitroarenes with Other Active Groups by DNA binding by
OASIS v.1.3
Domain
logical expression index: "j"
Referential
boundary: The
target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion
formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo AND SN1 >>
Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding
by OECD
Domain
logical expression index: "k"
Referential
boundary: The
target chemical should be classified as Acylation OR Acylation >> P450
Mediated Activation to Isocyanates or Isothiocyanates OR Acylation >>
P450 Mediated Activation to Isocyanates or Isothiocyanates >> Formamides
OR 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 >> Alkyl phenols OR
Michael addition >> P450 Mediated Activation to Quinones and
Quinone-type Chemicals >> Arenes OR Michael addition >> P450 Mediated
Activation to Quinones and Quinone-type Chemicals >> Hydroquinones OR No
alert found OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion
Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion formation
>> Aromatic nitro OR SN1 >> Nitrenium Ion formation >> Unsaturated
heterocyclic nitro by DNA binding by OECD
Domain
logical expression index: "l"
Referential
boundary: The
target chemical should be classified as No superfragment by
Superfragments ONLY
Domain
logical expression index: "m"
Parametric
boundary:The
target chemical should have a value of log Kow which is >= 1.87
Domain
logical expression index: "n"
Parametric
boundary:The
target chemical should have a value of log Kow which is <= 11.3
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (not irritating)
Respiratory irritation
Endpoint conclusion
- Endpoint conclusion:
- no study available
Additional information
Skin irritation:
Various studieshas been investigated for the test chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) to observe the potential for dermal irritation to a greater or lesser extent. The studies are based on in vivo experiments in rabbits for target chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) and its functionally similar read across substancesC.I. Pigment Red 3 (CAS No: 2425-85-6) and Sodium 4-(3-hydroxy-5-methyl-4-phenylazopyrazol-2-yl)benzenesulphonate(CAS No:6359-82-6).The predicted data using the OECD QSAR toolbox has also been compared with the experimental data and summarized as below;
In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, the skin irritation potential was estimated for test chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) .The chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) is estimated to be not irritating to skin of New Zealand White rabbits.
The European Commission (EC) - Scientific Committee on Cosmetology (SCC) {COMMISSION OF THE EUROPEAN COMMUNITIES; Brussels, Luxembourg, 1988} reported skin irritation study of read across chemical C.I. Pigment Red 3 (CAS No: 2425-85-6) on rabbits.TheC.I. Pigment Red 3 was applied on abraded and non-abraded skin of each rabbits under occlusive condition. No indication of skin irritation was observed. Hence the chemical C.I. Pigment Red 3(CAS No: 2425-85-6) was considered to be not irritating to theabraded and non-abraded skin of rabbits under occlusive condition.
The above results were further supported by the experimental study reported by European Commission (EC) - Scientific Committee on Cosmetology (SCC) {Environment and Quality of Life - Reports (Seventh Series), European Commission (EC) - Scientific Committee on Cosmetology (SCC), 1988} for read across substance Sodium 4-(3-hydroxy-5-methyl-4-phenylazopyrazol-2-yl)benzenesulphonate (CAS No:6359-82-6) on intact and abraded skin of rabbits. When rabbits were exposed with 100 mg of undiluted Sodium 4-(3-hydroxy-5-methyl-4-phenylazopyrazol-2-yl)benzenesulphonate(CAS No:6359-82-6), no skin irritating effects were observed. Thus the chemicalSodium 4-(3-hydroxy-5-methyl-4-phenylazopyrazol-2-yl)benzenesulphonate(CAS No:6359-82-6) was considered to be not irritating to the rabbits’ skin.
Thus 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 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) is unable to cause skin irritation and considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.
Eye irritation:
In different studies,the test chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) has been investigated for potential for ocular irritationto a greater or lesser extent. The studies are based on in vivo experiments in rabbits for target chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) and its structurally similar read across substance Edaravone(CAS No:-89-25-8) and functionally similar read across substance C.I. Pigment Red 3(CAS No: 2425-85-6).The predicted data using the OECD QSAR toolbox has also been compared with the experimental data and summarized as below;
In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, the eye irritation potential was estimated for test chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9).The chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) is estimated to be not irritating to eye of New Zealand White rabbits.
The Cosmetic Ingredient Review, CIR Expert Panel {Journal Of The American College of Toxicology, Volume 11, Number 4, 1992; Mary Ann Liebert, Inc., Publishers} conducted an eye irritation study in six albino (3/sex) rabbits for read across chemicalEdaravone(CAS No:-89-25-8).The test substance was applied into theconjunctival sac of the right eye of each rabbit at volume of 0.1 ml (0.66% solution of PMP in propylene glycol) and the left eye served as control. The eyes were not rinsed and examinedfor ocular lesionsafter24 hours and on days 2, 3, 4, and 7 using a cap lamp and also examined with a fluorescent lamp after injection of 2% sodium fluorescein solution.The ocular irritation index was observed to be 0.66/110 on day 1 and 0.00/110 0n the reaming days.As the ocular lesions were not persisted until 7 days observation period with ocular irritation index of 0.00, the test chemical Edaravone (CAS No:-89-25-8) was considered to be non-irritating to the eyes of albino rabbits.
The above results were further supported by an ocular irritation study of read across chemical C.I. Pigment Red 3 (CAS No: 2425-85-6) conducted on rabbits by European Commission (EC) - Scientific Committee on Cosmetology (SCC) {COMMISSION OF THE EUROPEAN COMMUNITIES; Brussels, Luxembourg, 1988}.The undiluted 100mg ofC.I. Pigment Red 3 was installed into the eye of each rabbits which produced Slight conjunctival changes only after one hour. Since the observed effects were cleared, the chemical C.I. Pigment Red 3(CAS No: 2425-85-6)was considered to be not irritating to therabbits’ eye.
Thus on the basis of available data for thetarget chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) and its structurally similar read across substanceEdaravone(CAS No:-89-25-8) and functionally similar read across substance C.I. Pigment Red 3(CAS No: 2425-85-6),it can be concluded thatchemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) is unable to cause eye irritation and considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.
Justification for classification or non-classification
The skin and eye irritation potential of test chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9)and its structurally similar read across substanceswere observed in various studies. The results obtained from these studies indicate that the chemical 4-aminobenzene-1,2-dicarbonitrile is unlikely to cause skin and eye irritation. Hence 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No: 6407-78-9) can be classified under the category “Not Classified” for skin and eye as per CLP.
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