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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18th April - 18th May 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
LLNA frequently gives false positives for irritating substances therefore Buehler test was used. The testing will also be submitted to other regulatory agencies that do not accept LLNA testing.
Species:
guinea pig
Strain:
Hartley
Sex:
female
Details on test animals and environmental conditions:
Prior to use, all animals were acclimated for at least five days. Animals were individually housed in wire mesh suspension cages. The animals were maintained on a 12-hour cycle light controlled room, at a temperature of 64° - 79°F and a relative humidity of 30-70%. The animals were maintained according to the recommendations contained in the National Academy Press 2011: “Guide for the Care and Use of Laboratory Animals.” The animals were supplied Purina Guinea Pig Chow and tap water ad libitum during both acclimation and test periods. Tox Monitor Laboratories has daily access to feed analysis; water analysis from the city of Chicago is on file. There were no contaminants in either the feed or the water that would be expected to affect the outcome of this study.
Route:
epicutaneous, semiocclusive
Vehicle:
water
Remarks:
Deionised
Concentration / amount:
0.4ml
Day(s)/duration:
6 hours
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
No.:
#20
Route:
epicutaneous, semiocclusive
Vehicle:
water
Remarks:
deionised
Concentration / amount:
0.4ml
Day(s)/duration:
6 hours
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
20 Female guinea pigs
Details on study design:
The irritation phase was conducted to determine the irritation potential of the test substance The irritation potential of the test substance at levels of 100%, 75%, 50% and 25% were evaluated in one group of two animals. The position of the different concentrations of the test substance on the animals was varied to adjust for possible site-to-site variation in response. The day prior to test substance exposure, the hair was removed from each of the animal's backs using a small animal clipper. Closed patches were applied to the animals in the following manner. A 0.4 ml quantity of each test preparation was applied directly into a 25 mm Hilltop Chamber®. The animals were held gently, and the chambers were applied as quickly as possible to the clipped left shoulder. The chambers were secured with Micropore tape and further secured with Kendall adhesive tape. Approximately six hours later, the tape and chambers were removed. The day following the irritation exposure all animals were scored at 24hr and 48hr. Based upon the irritation screen results the test substance was dosed as 100% concentration for the induction phase of the study, and 100% concentration, the highest non-irritating concentration, for the challenge phase of the study.
Challenge controls:
6 aninales wwere used as the naive control and 4 animals were kept for rechallenge if necessay.
Positive control substance(s):
yes
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100% concentration
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100% concentration
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
6
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
6
Remarks on result:
no indication of skin sensitisation
Group:
positive control
Remarks on result:
not measured/tested
Interpretation of results:
GHS criteria not met
Conclusions:
Following primary challenge oftest substanced at 100% concentration, the incidence of grade 1 response or greater in the test group (0 of 20) was compared to that of the naive control group (0 of 6). The incidence and severity of these responses were not significantly greater than those produced by the naive control group indicating that sensitization had not been induced. Therefore, in accordance with the CLP guidance, the test substance does not meet the classification criteria for skin sensitisation
Executive summary:

The dermal sensitization potential for the test substance was conducted utilizing a Buehler Technique Guinea Pig Sensitization Protocol. The test substance was evaluated for sensitization potential by applying 0.4 ml at a 100% concentration directly into Hilltop Chambers® and applying them to the clipped left shoulder of twenty albino guinea pigs in the following manner: The animals were held gently, and the chambers were applied as quickly as possible to the clipped left shoulder. The chambers were secured with Micropore tape and further secured with Kendall adhesive tape. Approximately six hours later, the tape and chambers were removed. Two additional induction doses were conducted following the same procedure, at

weekly intervals. Two weeks after the final application the animals received a topical primary challenge dose (6 hour contact) of the test substance at 100% concentration, on a naive site located on the right shoulder. Animals were scored for irritation at 24 and 48 hours after initiation of the primary challenge application. Ten guinea pigs served as a naive control group, and remained untreated through the induction phase. Six naive control animals received only the primary challenge dose, at a 100% concentration. The four remaining guinea pigs were designated for a re-challenge, if necessary. Following primary challenge of test sunstamce at 100% concentration, the incidence of grade 1 response or greater in the test group (0 of 20) was compared to that of the naive control group (0 of 6). The incidence and severity of these responses were not significantly greater than those produced by the naive control group indicating that sensitization had not been induced. Therefore, in accordance with the CLP guidance, the test substance does not meet the classification criteria for skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)

Justification for classification or non-classification

Following primary challenge oftest substanced at 100% concentration, the incidence of grade 1 response or greater in the test group (0 of 20) was compared to that of the naive control group (0 of 6). The incidence and severity of these responses were not significantly greater than those produced by the naive control group indicating that sensitization had not been induced. Therefore, in accordance with the CLP guidance, the test substance does not meet the classification criteria for skin sensitisation