Hydroquinone

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Observations on dermal irritation effects during an acute dermal toxicity study with occlusive application for 24 hrs at a test concentration similar to OECD Guideline 404; study acceptable to waive a skin irritation study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Hydroquinone: Acute and subchronic toxicity studies with emphasis on neurobehavioral and nephrotoxic effects.

Author:

Topping DC, Bernard LG, O'Donoghue JL, English JC

Year:

2007

Bibliographic source:

Food Chem Toxicol 45, 70 - 78

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Dermal effects observed during acute dermal toxicity study

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Hydroquinone

EC Number:

204-617-8

EC Name:

Hydroquinone

Cas Number:

123-31-9

Molecular formula:

C6H6O2

IUPAC Name:

hydroquinone

Details on test material:

- Name of test material (as cited in study report): hydroquinone
- Analytical purity: at least 99%
- Lot/batch No.: no data
- Stability under test conditions: test substance assumed to be stable under test conditions

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Covance Reseaerch Products, Denver, PA, USA
- Age at study initiation: at least 3 mo
- Body weight at study initiation: males 2.329-2.492 kg, females 2.040-2.592 kg
- Fasting period before study: no
- Housing: single
- Diet: PMI #5325 ad libitum
- Water: ad libitum
- Acclimation period: 5 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.8-22.9
- Humidity (%): 47.8-70
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

occlusive

Preparation of test site:

shaved

Vehicle:

other: moistened with water

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg

Duration of treatment / exposure:

24 h

Observation period:

14 d

Number of animals:

5 males and 5 females

Details on study design:

TEST SITE
- Area of exposure: dorsal skin
- % coverage: 10% of body surface
- Type of wrap if used: occlusive wrap (no further data)


REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 24 h


SCORING SYSTEM: only qualitative visual inspection of effects

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Remarks:

Qualitative assessment of skin irritation.

Basis:

mean

Remarks:

no individual data reported. Dermal application for 24 hours only

Time point:

24/48/72 h

Score:

ca. 0

Remarks on result:

other: Score of 0 assumed as default value for absence of adverse skin effects

Results 2

Irritation parameter:

edema score

Remarks:

Qualitative assessment of skin irritation.

Basis:

mean

Remarks:

No individual data reported. Dermal application for 24 hours only

Time point:

24/48/72 h

Score:

ca. 0

Remarks on result:

other: Score of 0 assumed as default value for absence of adverse skin effects

Irritant / corrosive response data:

No adverse dermal effects reported

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the absence of any dermal effects at the application site, there was no indication of skin irritation in rabbits during a dermal toxicity study with test concentrations comparable to those used for skin irritation studies. A more severe test condition with a 24-hour occlusive application was applied than is usual for skin irritation studies according to OECD Guideline 404 .

Executive summary:

Groups of 5 male and 5 female rabbits were exposed to HQ moistened with water for 24 h under an occlusive dressing during a dermal toxicity study and skin findings were reported qualitatively (no skin scoring system applied to describe findings). These test conditions deviate from OECD Guideline 404 which requests a 4-h semi-occlusive exposure. However, as the test concentrations of 27-36 mg/cm², which were estimated based on the applied dose of 2000 mg/kg bw, are comparable to the 30 mg/cm² requested by OECD Guideline 404, this study can be used for the assessment of skin irritation. No adverse dermal effects were reported indicating the absence of an irritating potential of pure HQ (no vehicles used) under the conditions of this test.