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EC number: 204-617-8 | CAS number: 123-31-9
- 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
Skin sensitisation
Administrative data
- Endpoint:
- skin sensitisation: in vivo (non-LLNA)
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- no data
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Remarks:
- Modified Magnusson and Kligman procedure. The HQ experiment included only 4 animals per group. Challenge applications were open.
Data source
Reference
- Reference Type:
- publication
- Title:
- Experimental study on cross-reactivity of α-arbutin toward p-phenylenediamine and hydroquinone in guinea pigs
- Author:
- To-o K., Nomura K., Sugimoto K., Bishimura T., Kuriki T., Itoh M.
- Year:
- 2 010
- Bibliographic source:
- J. Dermatol. 37: 455-462
Materials and methods
Test guideline
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- In principle the methodology was similar to OECD Guideline 406 (Skin Sensitisation) except the HQ sensitisation assay included a smaller number of animals (4 animals/group) and open application was used at challenge.
- GLP compliance:
- not specified
- Remarks:
- publication, University laboratories
- Type of study:
- guinea pig maximisation test
- Justification for non-LLNA method:
- Data from a research organization; not originally produced for regulatory purposes.
Test material
- Reference substance name:
- Hydroquinone
- EC Number:
- 204-617-8
- EC Name:
- Hydroquinone
- Cas Number:
- 123-31-9
- Molecular formula:
- C6H6O2
- IUPAC Name:
- hydroquinone
- Test material form:
- not specified
- Details on test material:
- - Name of test material : Hydroquinone
- Physical state: no data
- source: Wako Pure Chemicals Industries, Osaka, Japan
Constituent 1
In vivo test system
Test animals
- Species:
- guinea pig
- Strain:
- Dunkin-Hartley
- Sex:
- female
- Details on test animals and environmental conditions:
- TEST ANIMALS
- Source: no data
- Age at study initiation: no data
- Weight at study initiation: 400g
- Housing: individual cages
- Diet (e.g. ad libitum): standard solid diet ad libitum (RC-4 oriental Yeast, Osaka, Japan)
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: no data
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 +/- 2°C
- Humidity (%): 55 +/- 10°C
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12 h light/dark cycle
IN-LIFE DATES: no data
Study design: in vivo (non-LLNA)
Inductionopen allclose all
- Route:
- intradermal and epicutaneous
- Vehicle:
- other: acetone 80%
- Concentration / amount:
- On day 0, intradermal injections at 3 different spots:
1) 0.05 ml emulsified mixture of FCA and saline
2) 0.05 ml of 2% hydroquinone in saline
3) 0.05 ml of 2% hydroquinone in emulsified mixture of FCA and saline (1:1)
Challengeopen allclose all
- Route:
- epicutaneous, open
- Vehicle:
- other: acetone 80%
- Concentration / amount:
- On day 0, intradermal injections at 3 different spots:
1) 0.05 ml emulsified mixture of FCA and saline
2) 0.05 ml of 2% hydroquinone in saline
3) 0.05 ml of 2% hydroquinone in emulsified mixture of FCA and saline (1:1)
- No. of animals per dose:
- 4 females/dose
- Details on study design:
- MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1 intradermal injection on day 0 and one topical application on day 7
- Site: shaved flanks
- Frequency of applications: single application
- Concentrations:
On day 0, intradermal injections at 3 different spots:
1) 0.05 ml emulsified mixture of FCA and saline
2) 0.05 ml of 2% hydroquinone in saline
3) 0.05 ml of 2% hydroquinone in emulsified mixture of FCA and saline (1:1)
On day 7, topical induction with 0.5 g of 1% hydroquinone in petrolatum applied under an occlusive patch for 48 hrs.
B. CHALLENGE EXPOSURE
- No. of exposures: one application
- Day(s) of challenge: day 21
- Exposure period: 24 hrs, open application
- Test groups: hydroquinone in 80% acetone
- Control group: vehicle (acetone at 80% in water)
- Site: flank regions that had been shaved 24h before challenge
- Concentrations: 0.2%, 2% or 20% hydroquinone (0.05 ml containing 0.1, 1, or 10 mg HQ)
- Evaluation (hr after challenge): 24h, 48h, 72 h - Challenge controls:
- none
- Positive control substance(s):
- no
- Remarks:
- Hydroquinone was the positive control in the study investigating cross-reactivity
Results and discussion
In vivo (non-LLNA)
Resultsopen allclose all
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- positive control
- Dose level:
- 0.2%
- No. with + reactions:
- 3
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- negative control
- Dose level:
- vehicle
- No. with + reactions:
- 0
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: vehicle. No with. + reactions: 0.0. Total no. in groups: 4.0.
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- test chemical
- Dose level:
- 0.2%
- No. with + reactions:
- 3
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.2%. No with. + reactions: 3.0. Total no. in groups: 4.0.
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- test chemical
- Dose level:
- 2%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 2%. No with. + reactions: 4.0. Total no. in groups: 4.0.
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- positive control
- Dose level:
- 2%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- test chemical
- Dose level:
- 20%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 20%. No with. + reactions: 4.0. Total no. in groups: 4.0.
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- positive control
- Dose level:
- 20%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- negative control
- Dose level:
- vehicle
- No. with + reactions:
- 0
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: vehicle. No with. + reactions: 0.0. Total no. in groups: 4.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- test chemical
- Dose level:
- 0.2%
- No. with + reactions:
- 3
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 0.2%. No with. + reactions: 3.0. Total no. in groups: 4.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- positive control
- Dose level:
- 0.2%
- No. with + reactions:
- 3
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- test chemical
- Dose level:
- 2%
- No. with + reactions:
- 3
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 2%. No with. + reactions: 3.0. Total no. in groups: 4.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- positive control
- Dose level:
- 2%
- No. with + reactions:
- 3
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- test chemical
- Dose level:
- 20%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 20%. No with. + reactions: 4.0. Total no. in groups: 4.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- positive control
- Dose level:
- 20%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- other: 3rd reading
- Hours after challenge:
- 72
- Group:
- negative control
- Dose level:
- vehicle
- No. with + reactions:
- 0
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: negative control. Dose level: vehicle. No with. + reactions: 0.0. Total no. in groups: 4.0.
- Reading:
- other: 3rd reading
- Hours after challenge:
- 72
- Group:
- test chemical
- Dose level:
- 0.2%
- No. with + reactions:
- 2
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 0.2%. No with. + reactions: 2.0. Total no. in groups: 4.0.
- Reading:
- other: 3rd reading
- Hours after challenge:
- 72
- Group:
- positive control
- Dose level:
- 0.2%
- No. with + reactions:
- 2
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- other: 3rd reading
- Hours after challenge:
- 72
- Group:
- test chemical
- Dose level:
- 2%
- No. with + reactions:
- 2
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 2%. No with. + reactions: 2.0. Total no. in groups: 4.0.
- Reading:
- other: 3rd reading
- Hours after challenge:
- 72
- Group:
- positive control
- Dose level:
- 2%
- No. with + reactions:
- 2
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
- Reading:
- other: 3rd reading
- Hours after challenge:
- 72
- Group:
- test chemical
- Dose level:
- 20%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 20%. No with. + reactions: 4.0. Total no. in groups: 4.0.
- Reading:
- other: 3rd reading
- Hours after challenge:
- 72
- Group:
- positive control
- Dose level:
- 20%
- No. with + reactions:
- 4
- Total no. in group:
- 4
- Remarks on result:
- other: Hydroquinone was the positive control, see details under test chemical
Applicant's summary and conclusion
- Interpretation of results:
- Category 1B (indication of skin sensitising potential) based on GHS criteria
- Conclusions:
- The results showed the sensitising potential of Hydroquinone following intradermal induction at 2%, followed by an occlusive topical induction at 0.2, 2 or 20% in 80% acetone, and challenge with open applications at the same dose levels. Based on criteria described in CLP Regulation (EC) 1272/2008, the substance meets the criteria of sensitiser sub-category 1B (≥ 30 % responding at > 1 % intradermal induction dose).
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