Registration Dossier

Administrative data

skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19 August 1986 to 22 August 1986
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Study was performed prior to OECD guidelines and was not GLP compliant. Test method was similar to OECD 404 with the exceptions that the test material was applied for a 24-hour exposure and sites were only scored at 24 and 72 hours. Sufficient information was available for hazard classification per Annex VI of the CLP criteria.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
other: U.S. CPSC CFR 16 Section 1500.41
GLP compliance:

Test material

Constituent 1
Reference substance name:
Lauryl imidazole
Lauryl imidazole
Test material form:
other: Liquid
Details on test material:
- Name of test material (as cited in study report): Lauryl imidazole
- Substance type: Pure active substance
- Physical state: Liquid
- Analytical purity: 99%
- Purity test date: 22 July 1986
- Lot/batch No.: Batch 0001

Test animals

New Zealand White
Details on test animals or test system and environmental conditions:
- Source: Froxfield Rabbits, Petersfield, Hampshire, England
- Age at study initiation: 10-12 weeks old
- Weight at study initiation: 2.2-2.7 kg
- Housing: Individually in metal cages with perforated floors.
- Diet (e.g. ad libitum): SDS standard Rabbit Diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum
- Acclimation period: acllimated (length of time not reported)

- Temperature (°C): 19
- Humidity (%): 30-70
- Air changes (per hr): 19
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 19 August 1986 To: 22 August 1986

Test system

Type of coverage:
Preparation of test site:
other: one side intact, one abraded
unchanged (no vehicle)
Amount / concentration applied:
- Amount(s) applied (volume or weight with unit): 0.5 mL
Duration of treatment / exposure:
The test article remained in contact with the skin for 24 hours.
Observation period:
The treated sites were examined 24 and 72 hours after application of the test article.
Number of animals:
Details on study design:
- Area of exposure: Each site (intact and abraded) was covered with a 2.5 cm x 2.5 cm portion of gauze.
- Type of wrap if used: Elastoplast covered in plaster

- Washing (if done): sites were wiped to remove any residual test substance
- Time after start of exposure: 24 hours

SCORING SYSTEM: Erythema: 0-4, Edema: 0-4

Results and discussion

In vivo

Irritation parameter:
primary dermal irritation index (PDII)
Time point:
other: 24, 72 hours
ca. 4.7
no data
Irritant / corrosive response data:
Severe dermal reactions, with necrosis and slight to moderate edema, were observed at both sites of one animal through 72 hours after exposure. Well-defined erythema (scores: 2) with slight to moderate edema (scores: 2-3) was observed in the five remaining animals at 24 hours after exposure. Well defined to moderate erythema (scores: 2-3) with very slight to moderate edema (scores: 1-3) was observed in these 5 animals at the 72 hour observation time. Blanching was observed in all animals at 24 hours post-exposure.

Applicant's summary and conclusion

Interpretation of results:
not classified
Migrated information Criteria used for interpretation of results: EU
Based on the results of this study, the test article is a dermal irritant and is not classified according to CLP criteria.
Executive summary:

The primary skin irritation potential of the test article (slightly yellow liquid, purity 99% CASRN 4303-67-7, batch 0001) was evaluated in New Zealand White rabbits. The procedure was based on the method prescribed by the CPSC of the US in 16 CFR 1500.41. The hair was clipped from the dorsal skin of six female rabbits. Immediately prior to test article application, a 2.5 cm square area of the right side of the spine was abraded with the tip of a scalpel blade. A similar site on the left side of each animal remained intact. A 0.5 mL aliquot of the test article was applied under a 2.5 cm square gauze pad to one abraded and one intact site per animal. The sites were occluded with elastic dressing for 24 hours and at the end of exposure the sites were wiped to remove any residual test article. Observations for skin irritation (erythema and edema) were recorded at 24 and 72 hours after exposure. For intact skin, the means of the 24- and 72 -hour scores for erythema for the six animals were 2, 2, 2, 2, 4 (with necrosis), and 2. For intact skin, the means of the 24- and 72 -hour scores for edema for the six animals were 2.5, 2, 2, 2.5, 2, and 2.5. Blanching was observed in all animals at 24 hours post-exposure. Hyperkeratinization was observed in all animals at 72 hours after exposure. The Primary Irritation Index (PII) including intact and abraded scores was 4.7. Based on the results of this study, the test article is a mild dermal irritant and is not classified for skin irritation according to CLP criteria.