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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Remarks:
Buehler Test
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From March 14, 2017 and April 13, 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)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
An LLNA study was not conducted as the substance is a surfactant. Surfactants have been shown to often give false-positive results in LLNA studies.

Test material

Constituent 1
Reference substance name:
N,N-bis(2-hydroxyethyl)undec-10-enamide
EC Number:
262-114-9
EC Name:
N,N-bis(2-hydroxyethyl)undec-10-enamide
Cas Number:
60239-68-1
Molecular formula:
C15H29NO3
IUPAC Name:
N,N-Bis(2-hydroxyethyl)undec-10-enamid
Test material form:
liquid
Details on test material:
The test substance is the reaction product of 10-undecenoicacid methyl ester with diethanolamine (DEA). The methanol formed in the process is removed by distillation. The final product is a clear liquid at 20 °C and 101.3 kPa.
Specific details on test material used for the study:
Appearance: yellow paste

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
female
Details on test animals and environmental conditions:
Young adult, female Hartley guinea pigs from a USDA licensed supplier were used. The animals weighed 339 – 440 g at the start of the study. 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 supplied Purina Guinea Pig Chow and tap water ad libitum during both acclimation and test periods.

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
20%
Day(s)/duration:
6 h
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challenge
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
5%
Day(s)/duration:
14 d after primary challenge, 6 h contact time
No. of animals per dose:
A total of 32 animals were utilized. Twenty test animals, ten negative control animals, and two pilot animals were used.
Details on study design:
Exposure of the guinea pigs was divided into three phases: irritation screening (1), induction (2), and challenge (3).

1. The irritation potential of the test substance at levels of 40, 20, 10 and 5% were evaluated in one group of two animals. Four levels of test substance were evaluated per animal. 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.

2. The left shoulder of each test animal was clipped with a small animal clipper the day before exposure. The animals were held gently and the chambers were applied as previously described under the "Irritation Screening" section. Two additional induction doses were conducted following the same procedure, at weekly intervals. After the last induction exposure, the animals were left untreated for two weeks (14 days) before primary challenge.

3. Two weeks after the final application the animals received a topical primary challenge dose (6 hour contact) of the test substance, at 5% concentration, on a naive site located on the right shoulder. The same exposure procedure as for the "Induction Phase" was used, except the Hilltop Chambers were applied to a skin site that had not been previously exposed. Animals were scored for irritation at 24 and 48 hours after initiation of the primary challenge.

The day following the primary challenge exposure all animals were scored. The results of the primary challenge and rechallenge (if performed) are expressed in terms of both incidence and severity of responses and an assessment by comparison of responses in the test group to those of the corresponding control.
Challenge controls:
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 5% concentration. The four remaining guinea pigs were designated for a re-challenge, if necessary.
Positive control substance(s):
no

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
5%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no effects
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
5%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no effects
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
primary challenge dose, at a 5% concentration
No. with + reactions:
0
Total no. in group:
6
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
primary challenge dose, at a 5% concentration
No. with + reactions:
0
Total no. in group:
6
Remarks on result:
no indication of skin sensitisation
Key result
Group:
positive control
Remarks on result:
not measured/tested

Any other information on results incl. tables

The test substance was dosed at a 20% concentration for the induction phase and a 5% concentration for the challenge phase of the study. 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.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the study conditions, 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. The test substance was therefore considered not sensitizing to Guinea pig skin.
Executive summary:

A study was conducted to determine the skin sensitisation potential of the test substance according to OECD Guideline 406 and US EPA OPPTS 870.2600, in compliance with GLP. This Buehler test was realised on female albino Guinea pigs. A total of 32 animals were utilized; twenty test animals, ten negative control animals, and two pilot animals were used. The test substance was evaluated for sensitization potential by applying 0.4 ml at a 20% concentration directly into Hilltop Chambers® and applying them to the clipped left shoulder of twenty albino guinea pigs (induction phase). 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 6 h 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 h contact) of the test substance at 5% concentration, on a naive site located on the right shoulder. Animals were scored for irritation (intensity and severity) 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 5% concentration. The four remaining guinea pigs were designated for a re-challenge, if necessary. Following primary challenge of the test substance at 5% 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. Under the study conditions, the test substance was therefore considered not sensitizing to Guinea pig skin (Kukulinski, 2017).

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