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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study done according to Buehler protocol and reviewed by Quality Assurance Unit

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1984
Report Date:
1984

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
yes
Remarks:
various induction and challenge doses were incorporated to determine dose-response; cross challenges were performed
Principles of method if other than guideline:
various induction and challenge doses were incorporated to determine dose-response; cross challenges were performed
GLP compliance:
no
Remarks:
prior to GLP, Quality Assurance review
Type of study:
Buehler test
Justification for non-LLNA method:
The Buehler test is a challenge assay and more appropriate for determining skin sensitization of highly reactive substances like diisocyanates. For this substance group the LLNA often provides over-predictive results

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 4,4'-methylenediphenyl diisocyanate
- Molecular weight (if other than submission substance): 230
- Physical state: clear colorless liquid
- Storage condition of test material: room temperature, under nitrogen blanket
- Other: Supplier: American Cyanimid, Wayne, New Jersey, USA

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hazleton-Dutchland Laboratory Animals, Denver, PA
- Age at study initiation: 5-6 weeks
- Weight at study initiation: Males = 307 - 480 grams; Females = 299 - 462 grams
- Housing: Husbandry was according to current accepted guidelines of "Good Animal Husbandry": housed in stainless steel cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): (65 -75 degrees F)
- Humidity (%): 30-70%
- Photoperiod (hrs dark / hrs light): 12 hours light, 12 hours dark


IN-LIFE DATES: From: To:

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: anhydrous acetone:olive oil (1:1)
Concentration / amount:
Induction: 10mM (0.25%), 30mM (0.75%), 100 mM (2.5%)
Challenge: 0.03mM (0.00075%), 0.3mM (0.0075%), 3mM (0.075%), 10mM (0.25%), 30mM (0.75%),
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: anhydrous acetone:olive oil (1:1)
Concentration / amount:
Induction: 10mM (0.25%), 30mM (0.75%), 100 mM (2.5%)
Challenge: 0.03mM (0.00075%), 0.3mM (0.0075%), 3mM (0.075%), 10mM (0.25%), 30mM (0.75%),
No. of animals per dose:
15
Details on study design:
RANGE FINDING TESTS: Six animals were treated topically with concentrations of 1.0, 0.3, 0.1, 0.003 Molar material in 100% olive oil or in 1:1 mixture with olive oil and anhydrous acetone. The test material (30 ul) was applied directly to the skin under occlusion. After 6 hours, the patches were removed and the skin wiped free of excess material. Observations were made at 24 and 48 hours. Treated sites were scored according to Draize.


MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 hours
- Test groups: 15 animals per group, approximately equal by sex, were administered 50 microliter test substance under occlusion
- Control group: 3 males and 3 females; no treatment
- Site: anterior portion of right flank
- Frequency of applications: 1 time a week
- Duration: 3 weeks
- Concentrations: 10mM (0.25%), 30mM (0.75%) 100 millimolar(2.5%) MDI


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: day 14
- Exposure period: 6 hours
- Test groups: 25 microliters of five different concentrations under occlusion
- Control group: same challenge exposure as treated animals
- Site: opposite flank from site used for induction
- Concentrations: 0.03mM (0.00075%), 0.3mM (0.0075%), 3mM (0.075%), 10mM (0.25%), 30mM (0.75%) MDI
- Evaluation (hr after challenge): 24 and 48 hr


OTHER:
Challenge controls:
6 animals with no induction were challenged with: 0.03mM (0.00075%), 0.3mM (0.0075%), 3mM (0.075%), 10mM (0.25%), 30mM (0.75%) MDI
Positive control substance(s):
yes
Remarks:
m-TMI

Results and discussion

Positive control results:
m-TMI = 100%

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
low, 10mM (0.25%)
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
no clinical findings
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: low, 10mM (0.25%). No with. + reactions: 0.0. Total no. in groups: 15.0. Clinical observations: no clinical findings.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
middle, 30mM (0.75%)
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
no clinical findings
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: middle, 30mM (0.75%). No with. + reactions: 0.0. Total no. in groups: 15.0. Clinical observations: no clinical findings.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
high, 100mM (2.5%)
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
no clinical findings
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: high, 100mM (2.5%). No with. + reactions: 0.0. Total no. in groups: 15.0. Clinical observations: no clinical findings.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
low, 10 mM (0.25%)
No. with + reactions:
1
Total no. in group:
15
Clinical observations:
barely perceptible, non-confluent erythema (equivocal) in 2/15 animals
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: low, 10 mM (0.25%). No with. + reactions: 1.0. Total no. in groups: 15.0. Clinical observations: barely perceptible, non-confluent erythema (equivocal) in 2/15 animals.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
middle, 30mM (0.75%)
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
barely perceptible, non-confluent erythema (equivocal) in 4/15 animals
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: middle, 30mM (0.75%). No with. + reactions: 0.0. Total no. in groups: 15.0. Clinical observations: barely perceptible, non-confluent erythema (equivocal) in 4/15 animals.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
high, 100mM (2.5%)
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
barely perceptible, non-confluent erythema (equivocal) in 5/15 animals
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: high, 100mM (2.5%). No with. + reactions: 0.0. Total no. in groups: 15.0. Clinical observations: barely perceptible, non-confluent erythema (equivocal) in 5/15 animals.
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
500mM
No. with + reactions:
15
Total no. in group:
15
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 500mM. No with. + reactions: 15.0. Total no. in groups: 15.0.

Any other information on results incl. tables

Treated animals showed a very low degree of change in irrtation scores over the induction period.

Animals treated with low, mid or high induction concentrations exhibited equivocal responses to high challenge concentrations of the test material. Only one definitive response (score of 1) was seen at a low induction dose to the mid-high challenge concentration.

 Induction dose  Challenge dose  Responders
 10mM (0.25%)  0.03mM (0.00075%)   0/15
    0.3mM (0.0075%)   0/15
    3mM (0.075%)   0/15
    10mM (0.25%)   1/15
   30mM (0.75%)   0/15
  30mM (0.75%)   0.03mM (0.00075%)   0/15
    0.3mM (0.0075%)   0/15
    3mM (0.075%)   0/15
    10mM (0.25%)   0/15
    30mM (0.75%)   0/15
 100mM (2.5%)   0.03mM (0.00075%)   0/15
    0.3mM (0.0075%)   0/15
    3mM (0.075%)   0/15
    10mM (0.25%)   0/15
    30mM (0.75%)  0/15

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information The study data suggest that MDI possesses some potential to produce dermal sensitization.
Conclusions:
MDI has the potential to induce dermal sensitization, however the dose response data indicates that this is a threshhold phenomena with a study NEL of 100 mM (2.5%)
Executive summary:

This dermal sensitization study demonstrated that at induction doses of 0.25%, 0.75%, and 2.5%, MDI did not exhibit sensitzation potential at various challenge doses. This study, therefore, demonstrates a threshold for the induction of dermal sensitzation.