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Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
January 16 - February 17, 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
GLP compliance:
yes (incl. QA statement)
Type of study:
Buehler test
Justification for non-LLNA method:
A dermal sesitisation test in Guinea pig was already available.

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
428-790-6
EC Name:
-
Cas Number:
72963-72-5
Molecular formula:
C17H22N2O4
IUPAC Name:
[2,5-dioxo-3-(prop-2-yn-1-yl)imidazolidin-1-yl]methyl (1R,3R)-2,2-dimethyl-3-(2-methylprop-1-en-1-yl)cyclopropane-1-carboxylate; [2,5-dioxo-3-(prop-2-yn-1-yl)imidazolidin-1-yl]methyl (1R,3S)-2,2-dimethyl-3-(2-methylprop-1-en-1-yl)cyclopropane-1-carboxylate
Test material form:
liquid: viscous
Details on test material:
Name: Imiprothrin
Appearance: viscous liquid
Colour: amber

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
Number of Animals: 34
Number of Groups: 3
Sex: Male and Female. All females assigned to test were nulliparous and non-pregnant.
Species/Strain: Guinea pigs/Hartley albino.
Age/Body Weight: Preliminary Irritation Group: Young adult (male or female)
Test and Naive Control Groups: Young adult males/457-567 grams at experimental start.
Housing: The animals were group housed in plastic solid bottom polycarbonate caging,
Animal Room Temperature and Relative Humidity Ranges: 19-23ºC and 43-58%, respectively.
Animal Room Air Changes/Hour: 12.
Photoperiod: 12-hour light/dark cycle
Acclimation Period: 21-48 days
Food/water: ad libitum

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
four-tenths of a milliliter
Day(s)/duration:
6 hours
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Concentration / amount:
four-tenths of a milliliter
Day(s)/duration:
2
No. of animals per dose:
Preliminary Irritation Group: 4
Test Group: 20
Naive Control Group: 10
Details on study design:
Induction Phase
Once each week for three weeks, four-tenths of a milliliter of the neat test substance was applied to the left side of each test animal using an occlusive 25 mm Hill Top Chamber. The chambers were secured in place and wrapped with non-allergenic Durapore adhesive tape to avoid dislocation of the chambers and to minimize loss of the test substance for six hours. After the 6-hour exposure period, the chambers were removed and the test sites were gently cleansed with a 3% soap solution followed by tap water and a clean paper towel to remove any residual test substance. Approximately 24 and 48 hours after each induction application, readings were made of local reactions (erythema) .

Challenge Phase
Twenty-seven days after the first induction dose, four-tenths of a milliliter of the neat test substance (100%, HNIC) was applied to a naive site on the right side of each animal as a challenge dose, using the procedures described above. These sites were evaluated for a sensitization response (erythema) approximately 24 and 48 hours after the challenge application.

In addition to the test animals, 10 guinea pigs from the same shipment were maintained under identical environmental conditions and were treated with the HNIC of the test substance at challenge only. These animals constituted the "naive control" group.
Positive control substance(s):
yes
Remarks:
alpha-Hexylcinnamaldehyde (HCA)

Results and discussion

Positive control results:
Induction Phase:
Historical Positive Control Animals (100% HCA): Very faint erythema (0.5) was noted at most positive control sites during the induction phase. Faint erythema (1) was noted at five sites 24 and/or 48 hours after the second and/or third induction application.

Challenge Phase:
Historical Positive Control Animals (100% HCA): Six of ten positive control animals exhibited signs of a sensitization response (faint erythema [1]) 24 hours after the challenge application. Positive responses persisted at five of the positive control sites from 24 hours through 48 hours. Very faint erythema (0.5) was noted at three other sites at 24 and/or 48 hours after the challenge application.
Historical Naive Control Animals (100% HCA): Very faint erythema (0.5) was noted at four naive control sites at 24 and 48 hours after the challenge application.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100% test substance
No. with + reactions:
0
Total no. in group:
20
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100% test substance
No. with + reactions:
0
Total no. in group:
20
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
100 % HCA
No. with + reactions:
6
Total no. in group:
10
Clinical observations:
faint erythema
Remarks on result:
other: Historical control data
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
100 % HCA
No. with + reactions:
5
Total no. in group:
10
Clinical observations:
faint erythema
Remarks on result:
other:
Remarks:
Historical control data
Group:
negative control
Remarks on result:
not measured/tested

Any other information on results incl. tables

There was no dermal irritation observed at any test site during the induction phase.

There was no dermal irritation observed at any test site during the challenge phase.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Based on the results of this study, the test substance is not considered to be a contact sensitizer.