4,4'-methylenebis(cyclohexylamine)

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27.02.1991 to 22.03.1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4,4'-methylenebis(cyclohexylamine)

EC Number:

217-168-8

EC Name:

4,4'-methylenebis(cyclohexylamine)

Cas Number:

1761-71-3

Molecular formula:

C13H26N2

IUPAC Name:

4,4'-methylenedicyclohexanamine

Test material form:

other: liquid

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
Source: David Percival Ltd., Moston, Sandbach, Cheshire, U.K.
Strain: New Zealand White rabbit
Age at study initiation: twelve t o sixteen weeks
Sex: male and female
Weight at study initiation: 2.22 - 2.47 kg
Housing: individually in suspended metal cages
Diet(ad libitum):Spillers Rabbit Diet, Dalgety Agriculture Ltd., Almondsbury, Bristol
Water ad libitum

ENVIRONMENTAL CONDITIONS
Temperature: 18- 22 °C
Humidity: 50- 60 %
Air changes/ hour: 15
Photoperiod: 12 hours light/ 12 hours dark

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

0.5 ml

Duration of treatment / exposure:

3 minutes and approx 2.75 hours (4 hour exposure was terminated early)

Observation period:

1 hour, 24 hours, 48 hours and 72 hours following removal of the test material after the 3 minute exposure.
1 hour following removal of the test material after the 2.75 hour exposure.

Number of animals:

6

Details on study design:

The study was performed to assess the irritancy potential of the test material following single, semi -occluded applications to the intact rabbit skin for exposure periods o f 2 3/4 hours and 3 minutes (Safepharm Standard Method Number OECD 4). The method used followed the recommendations of the OECD Guidelines for Testing of Chemicals (1981) No. 404 "Acute Dermal Irritation/Corrosion" referenced as Method B4 in Commission Directive 84/449/EEC (which constitutes Annex V o f Council Directive 67/548/EEC).
The results may be used as a basis for classification and labelling under Annex VI o f Council Directive 67/548/EEC (as adapted to technical progress by Commission Directive 83/467/EEC).
The test system was chosen because the rabbit has been shown to be a suitable model for this type of study and is recommended in the test method.
The results of the study are believed to be of value in predicting the likely skin irritancy potential of the test material to man.

Approximately twenty-four hours prior to the commencement of the test, each of a group of three rabbits was prepared by closely clipping the fur from the dorsal flank areas using veterinary clippers.
Only animals with a healthy intact epidermis by gross observation were selected for the study. On the day of the test a suitable testsite was selected on the back of each rabbit. A quantity of 0.5 ml of the test material was introduced under a 2.5 cm x 2.5 cm gauze patch and placed i n position on the shorn skin. The patch was secured in position with a strip of surgical adhesive tape (BLENDERM: approximate size 2.5 cm x 4.0 cm).
To prevent the animals from interfering with the patches the trunk of each rabbit was wrapped in an elasticated corset (TUBIGRIP) and the animals were returned to their cages for the duration of the exposure period.
Approximately 2 3/4 hours after application the corset and patches were removed from each animal and any residual test material removed by gentle swabbing with cotton wool soaked in diethyl ether.

An additonal group of three rabbits was exposed to the test material underidentical conditions to the 2 3/4 hour exposure, except that the patches were removed three minutes after application to the skin. Approximately one hour following the removal of the patches, and 24, 48 and 72 hours later (where appropriate), the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize J.H. (1959).

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 165 min

Score:

6

Max. score:

12

Reversibility:

no data

Results 2

Irritation parameter:

erythema score

Remarks:

after 3 min exposure

Basis:

animal #1

Time point:

24/48/72 h

Score:

10

Max. score:

12

Reversibility:

not reversible

Results 3

Irritation parameter:

erythema score

Remarks:

after 3 min exposure

Basis:

animal #2

Time point:

24/48/72 h

Score:

6

Max. score:

12

Reversibility:

not reversible

Results 4

Irritation parameter:

erythema score

Remarks:

after 3 min exposure

Basis:

animal #3

Time point:

24/48/72 h

Score:

12

Max. score:

12

Reversibility:

not reversible

Results 5

Irritation parameter:

edema score

Remarks:

after 3 min exposure

Basis:

animal #1

Time point:

24/48/72 h

Score:

11

Max. score:

12

Reversibility:

not reversible

Results 6

Irritation parameter:

edema score

Remarks:

after 3 min exposure

Basis:

animal #2

Time point:

24/48/72 h

Score:

10

Max. score:

12

Reversibility:

not reversible

Results 7

Irritation parameter:

edema score

Remarks:

after 3 min exposure

Basis:

animal #3

Time point:

24/48/72 h

Score:

12

Max. score:

12

Reversibility:

not reversible

Irritant / corrosive response data:

2.75 hour exposure -
Severe dermal necrosis, haemorrhage of the dermal capillaries and loss of skin elasticity were noted at all treated skin sites, one hour after patch removal. The reactions extended beyond the treatment site in two animals and an isolated incident of bleeding was also noted.
An accurate evaluation o f the degree of oedema was not possible due to the other adverse dermal reactions.
All animals were killed for humane reasons and in accordance with Home Office regulations following the one hour observation.

3 minute exposure -
Very slight to well-defined erythema and haemorrhage of the dermal capillaries were noted at all treatment sites one hour after patch removal and persisted at two sites at the 24-hour observation. Well-defined erythema was also noted at one treatment site at the 48- and 72-hour observations. A hardened dark brown/black coloured scab, surrounded by well-defined erythema and with light brown discolouration of the epidermis was also noted at the remaining treatment sites at these times. An accurate evaluation of erythema was not possible at the 48- and 72-hour observations due to the severity of the other dermal reactions.
Very slight oedema was noted at all treatment sites one hour aafter patch removal with moderate to severe oedema noted at all other observation times. Evaluation of oedema was commonly precluded by other adverse dermal reactions.
Green/brown coloured areas of possible dermal necrosis indicative of dermal corrosion were noted at one treated skin site at the 24- and 48-hour observations.
All animals were killed for humane reasons and in accordance with Home Office regulations after the 72-hour observation.

Other effects:

not reported

Applicant's summary and conclusion

Conclusions:

The 3 minute exposure did not result in necrosis at the 1-hour observation period but one out of three animals exhibited necrosis at the 24-hour observation. The 2.75 hour exposure resulted in necrosis by the one hour post exposure observation. It was therefore determined that the test substance meets the criteria for classification as a Packing Group II, GHS 1B corrosive, and DSD R35 corrosive.

Executive summary:

In an OECD Guideline 404 study, rabbits were dermally exposed to PACM to assess skin irritancy/corrosivity. 

The test material was regarded as corrosive according to EEC labelling regulations.
The test material also produced a modified primary irritation index of 6.0 (based on values for erythema only).