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Administrative data

Description of key information

No reliable skin sensitization study was available for the test substance; therefore a read-across approach with the pharmacologically active ingredient Imazalil was used to cover this endpoint.

In a GLP Magnusson guinea pig maximization test (Tuens, 1990, K1) performed according to OECD Guideline 406, Imazalil showed a sensitization rate of 5%, which was below the threshold for classification as a skin sensitizer.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Remarks:
GPMT
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 1990-09-19 to 1990-10-13
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
Adopted May 12, 1981
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: The US Federal Register Vol. 50, No.188, subpart 798.4100
Version / remarks:
September 27, 1985
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
other: US EPA: Pesticide Assessment Guidelines, Subdibision F - Hazard Evaluation: Human and Domestic Animals - Series 81-6: Dermal Sensitization
Version / remarks:
Addendum 4 on Data Reporting (January 1988)
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
other: Agricultural Chemicals Law and Regulations Japan (II); Testing Guidelines for Toxicology Studies, pp. 27-29: Dermal Sensitization Toxicity Study
Version / remarks:
January 28, 1985
Deviations:
not specified
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The Murine Local Lymph Node Assay (LLNA) is the first-choice method for in vivo testing according to the REACH Regulation. However, this reliable GMPT was performed before entry into force of the REACH Regulation
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: G3A561
- Expiration date of the lot/batch: Not specified
- Purity: 98.1%
- Manufacturing Date: 1989-01-23


STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature in closed containers.
- Solubility and stability of the test substance in the solvent/vehicle: The stability of imazalil in 1% sesam oil (with or without FCA), 10% petrolatum, and 5% petrolatum was controlled and guaranteed. All mixes were prepared for immediate use.


Species:
guinea pig
Strain:
Pirbright-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Test facility permanent non-inbred laboratory colony
- Females (if applicable) nulliparous and non-pregnant: not applicable
- Age at study initiation: Not specified
- Weight at study initiation: 300-400g
- Housing: Housed in an air-conditioned room and placed individually in numbered metallic cages. The cages were placed in racks.
- Diet (e.g. ad libitum): "Hope-farms" standardized pellets administrated in slef-raising hoppers and fed ad libitum.
- Water (e.g. ad libitum): ad libitum
- Acclimation period: One-week
- Indication of any skin lesions: No

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Not specified
- Humidity (%): Not specified
- Air changes (per hr): Not specified
- Photoperiod (hrs dark / hrs light): Not specified
- IN-LIFE DATES: From: 1990-09-19 To:1990-10-13
Route:
intradermal
Vehicle:
other: sesam oil
Concentration / amount:
1%
Day(s)/duration:
day 0
Adequacy of induction:
other: produced no necrosis at the injection site
Route:
epicutaneous, occlusive
Vehicle:
petrolatum
Concentration / amount:
10%
Day(s)/duration:
day 7; 48h occlusive patch
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
petrolatum
Concentration / amount:
5%
Day(s)/duration:
day 21; 24 hours occlusive patch
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
2 main groups (vehicle induced and imazalil induced) of 20 animals each.
Details on study design:
RANGE FINDING TESTS:
The formulations used were chosen based upon a screen test which indicated that the 1% solution in sesam oil alone produced no necrosis at the injection site. The 10% powder in petolatum produced a slight erythema at the application site whereas the 5% powder in petrolatum did not result in erythema when applied to the skin of guinea-pigs during 24h under occlusive patch.

MAIN STUDY
A. INTRADERMAL INDUCTION - Day 0
- No. of exposures: Once
- Site: depilated nuchal area
- Concentrations:

The following injections were given:
- 2 injections of 0.1 mL of Freund's complete adjuvant blended with an equal amount of water
- 2 injections of 0.1 mL of the test article formulation close to the first 2 injections
- 2 injections of 0.1 mL of the test article formulation emulsified with Freund's complete adjuvant

Test groups: 1% solution in sesam oil
Control group: 100% sesam oil

B. EPICUTANEOUS INDUCTION - Day 7
- The test article and vehicle formulations were held in contact with the skin under an occlusive patch during 48 hours.
- The vehicle-induced group received the vehicle formulations.
- Scoring was perfromed 24 hours later.

C. CHALLENGE EXPOSURE - Day 21
- Two weeks after the epicutaneous induction a formulation of 5% imazalil in pertrolatum was applied epicutaneously on the left shaved flank under occlusive patch during 24 hours.

Challenge controls:
not specified
Positive control substance(s):
yes
Remarks:
DNCB
Positive control results:
A positive sensitizer, DNCB was additionally evaluted in a separate study (Exp no. 2216). A 100% sensitization rate was obtained 48 and 72h.
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
5% test item in petrolatum
No. with + reactions:
1
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
5% test item in petrolatum
No. with + reactions:
1
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
Vehicle only
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
vehicle only
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
positive control
Remarks on result:
positive indication of skin sensitisation
Remarks:
100% sensitization rate
Reading:
2nd reading
Hours after challenge:
72
Group:
positive control
Remarks on result:
positive indication of skin sensitisation
Remarks:
100% sensitization rate

Observations

All guinea-pigs survived the study. Body weights, which were recorded prior to and at the end of the study, were comparable between groups.

Interpretation of results:
GHS criteria not met
Conclusions:
As appears from these data and when compared to the results of the positive control study with DNCB (exp no. 2216) where a 100% sensitization rate was obtained 48 and 72h.
Based on the sensitization rate obtained after the challenge exposure, the study director classified the test item as weak sensitizer (sensitization rate between 0 and 8%). However accroding to the criteria laid out in the CLP regulation, Imazalil should not be classified as skin sensitizer.
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Data from the related substance imazalil base is used to cover this endpoint. The justification for read across is attached in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across source
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
5% test item in petrolatum
No. with + reactions:
1
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
5% test item in petrolatum
No. with + reactions:
1
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
vehicle only
No. with + reactions:
0
Total no. in group:
0
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
vehicle only
No. with + reactions:
0
Total no. in group:
0
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
positive control
Remarks on result:
positive indication of skin sensitisation
Remarks:
100% sensitization rate
Reading:
2nd reading
Hours after challenge:
72
Group:
positive control
Remarks on result:
positive indication of skin sensitisation
Remarks:
100% sensitization rate
Conclusions:
No reliable skin sensitization study is available for Imazalil sulfate. Therefore, reliable data from the supporting substance Imazalil is used to cover this endpoint. Imazalil was judged as not skin sesnsitizer. The same is assumed for Imazalil sulfate. Justification for this read across approach is included in IUCLID section 13.
Endpoint:
skin sensitisation: in vitro
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
an in vitro skin sensitisation study does not need to be conducted because adequate data from an in vivo skin sensitisation study are available
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Two dermal sensitization tests according to the Buehler method were performed with both the source and the target subtsances Imazalil and Imazalil sulphate, respectively (Wnorowski, 1997). These tests were not considered reliable enough (K3) to cover the endpoint because of the low number of animals tested in these tests (10), which is insufficient to be in line with the test guideline OECD 406 and ensure a firm conclusion on the skin sensitization potential of the test substance.

In the Magnusson guinea pig maximization test (Teuns, 1990, K1), the skin sensitization potential of Imazalil was tested on 20 guinea pigs.

Intradermal (1% Imazalil in sesame oil) and epicutaneous (10% Imazalil in petrolatum) induction followed by epicutaneous challenge ( 5% Imazalil in petrolatum) resulted in a sensitization rate of 5% on day 23 (48h after challenge) and day 24 (72h after challenge).

Although the study director concluded that Imazalil is a weak sensitizer based on a sensitization rate of 5%, the threshold for classification based on a GPMT test defined in the CLP regulation is not reached. Therefore Imazalil should not be classified as skin sensitizer based on the results of this test.

Justification for classification or non-classification

Based on the test results described above, the source substance Imazalil is not classified as a skin sensitizer, and this classification should apply to the target substance Imazalil sulphate.

However, a harmonised classification is available for Imazalil sulphate (Index numbers 613 -043 -01 -8 and 613-043 -00 -0) as Skin sens 1 (H317).