Methylcyclohexane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Basic data given. Limitations include 24 h occlusive exposure, reading time points only at 24 and 72 h , observation period only 72 h.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1982

Report date:

1982

Materials and methods

Principles of method if other than guideline:

Primary skin irritation study in rabbits according to Draize (Draize, J.H. (1965). Dermal Toxicity. In Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics. The Editorial Committee of the Association of Food and Drug Officials of the United States, pp. 46-59)

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Methylcyclohexane

EC Number:

203-624-3

EC Name:

Methylcyclohexane

Cas Number:

108-87-2

Molecular formula:

C7H14

IUPAC Name:

methylcyclohexane

Details on test material:

- Name of test material (as cited in study report): methyl cyclohexane
- Substance type: technical product
- Physical state: liquid
- Analytical purity: no data

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Laboratory Animals, Inc.
- Age at study initiation: adult
- Housing: individual
- Diet: Purina Lab Rabbit Chow®, ad libitum. Feed was periodically analyzed for concentrations of specified heavy metals, antibiotics, aflatoxin, pesticides, and nitrosamines
- Water: Tap water, ad libitum. The water was routinely analyzed on a retrospective basis for specified microorganisms, pesticides, heavy metals, alkalinity, and halogens.
- Quarantine: Minimum of 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

occlusive

Preparation of test site:

other: shaved (intact) and abraded

Vehicle:

unchanged (no vehicle)

Controls:

other: untreated sites of the same animal served as control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL

Duration of treatment / exposure:

24 h

Observation period:

72 h
Reading time points: 24 and 72 h

Number of animals:

3 males and 3 females

Details on study design:

TEST SITE
- Area of exposure: 6.5-9.7 cm² (1 - 1.5" square) intact or abraded skin on the back of the animal
- Type of wrap if used: The treated skin was covered with a gauze patch (two layers thick) held in place with Dermiclear brand transparent tape (Johnson and Johnson). The entire trunk of the animal was wrapped with a non-absorbent binder and the animal was immobilised in a stock for 24 h.

SCORING SYSTEM: Draize scoring system

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: mean over 24 and 72 h

Score:

0.5

Max. score:

4

Reversibility:

fully reversible within: 72 h

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Remarks on result:

other: animal found dead

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: mean over 24 and 72 h

Score:

0

Max. score:

4

Reversibility:

other: reversibility: not applicable

Results 4

Irritation parameter:

erythema score

Basis:

animal #4

Time point:

other: mean over 24 and 72 h

Score:

0.5

Max. score:

4

Reversibility:

fully reversible within: 72 h

Results 5

Irritation parameter:

erythema score

Basis:

animal #5

Time point:

other: mean over 24 and 72 h

Score:

1

Max. score:

4

Reversibility:

no data

Remarks:

on reversibility

Results 6

Irritation parameter:

erythema score

Basis:

animal #6

Time point:

other: mean over 24 and 72 h

Score:

0.5

Max. score:

4

Reversibility:

fully reversible within: 72 h

Results 7

Irritation parameter:

edema score

Basis:

mean

Remarks:

out of all 6 animals

Time point:

other: mean over 24 and 72 h

Score:

0

Max. score:

4

Reversibility:

other: reversibility: not applicable

Irritant / corrosive response data:

24 h post-application: very slight erythema was noted at all 5 abraded sites and 4 of 5 intact sites. No edema was noted in any animal.
72 h post-application: very slight erythema was noted at 1 of 5 abraded and 1 of 5 intact sites. No edema was noted in any animal.

Other effects:

No other dermal effects were observed throughout the study. One male animal was found dead prior to the 24 h reading, and was not replaced.

Any other information on results incl. tables

Table 1. Intact skin - Individual skin examination scores after 24h-exposure (Scoring according to Draize scheme)

Observation time	Rabbit no.
	1 male		2 male*		3 male		4 female		5 female		6 female
	Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema
24 h	1	0	-	-	0	0	1	0	1	0	1	0
72 h	0	0	-	-	0	0	0	0	1	0	0	0
Mean value 24 + 72 h	0.50	0.00	-	-	0.00	0.00	0.50	0.00	1.00	0.00	0.50	0.00
Mean value 24 + 72 h all animals	0.50	0.00

* Animal found dead prior to the 24 h observation.

Table 2. Abraded skin - Individual skin examination scores after 24h-exposure (Scoring according to Draize scheme)

Observation time	Rabbit no.
	1 male		2 male*		3 male		4 female		5 female		6 female
	Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema
24 h	1	0	-	-	1	0	1	0	1	0	1	0
72 h	0	0	-	-	0	0	0	0	0	0	1	0
Mean value 24 + 72 h	0.50	0.00	-	-	0.50	0.00	0.50	0.00	0.50	0.00	1.00	0.00
Mean value 24 + 72 h all animals	0.60	0.00

* Animal found dead prior to the 24 h observation.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Methylcyclohexane was tested for primary skin irritation in rabbits following the Draize method (Draize, J.H. (1965). Dermal Toxicity. In Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics. The Editorial Committee of the Association of Food and Drug Officials of the United States, pp. 46-59). A group of 3 male and 3 female rabbits was exposed to 0.5 mL of the undiluted test material applied onto both the intact and abraded skin for 24 h using an occlusive dressing. The treated skin was observed for reactions after patch removal and evaluations were made at 24 and 72 h post-application.
One male animal was found dead prior to the 24 h reading, and was not replaced. At 24 h post-application, very slight erythema was noted at 4/ 5 intact sites and at all 5 abraded sites. At 72 h post-application, very slight erythema was noted at 1/5 intact and 1/5 abraded sites. No edema was noted in any animal at any time. The study was terminated 72 h post-application; therefore, no information on the reversibility of the skin effects still seen at the 72 h reading is available. The individual mean erythema scores over 24 and 72 h were 0.5/0.0/0.5/1.0/0.5 for each intact skin site and 0.5/0.5/0.5/0.5/1.0 for each abraded site.

In this study, very slight erythema and no edema were observed in rabbits exposed to methylcyclohexane for 24 h under occlusive conditions; the effects being fully reversible in 4/5 animals within 72 h post-application. Therefore, the study results do not fulfil the classification criteria for skin irritation according to Regulation (EC) 1272/2008 and Directive 67/548/EEC.

CLP: not classified
DSD: not classified