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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:
02-2016-04-2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study was well conducted with no deficiences
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Principles of method if other than guideline:
not applicable
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
This test was done for another regulation outside from REACh.
Species:
guinea pig
Strain:
other: HA (BR)
Sex:
male
Details on test animals and environmental conditions:
Species: Cavia porcellus (guinea pig)
Strain: HA (BR)
Source: Charles River Canada
Sex: females
Body Weight Range: 309.8 - 347.8 g
Number of Animals: Treatment group – 20
Negative Control group - 10
Positive Control group - 5
Acclimatization Period: 7 days
Age at Study Start: 5-6 weeks
Animal Identification: Colour coding, cage labels

Guinea pigs were housed in separate quarters in solid bottom cages, 5 per cage.
Individual animals were identified by colour coding; the animal number and group
number also appeared on the outside of each cage to preclude mix-up. The animal
room environment was controlled (targeted ranges: temperature 18ºC to 26ºC, relative
humidity 30-70% minimum 10 air changes per hour) and monitored. The photo-cycle
was 12 hours light and 12 hours dark. Upon arrival all animals were submitted to a
general physical examination and all were found healthy and were admitted. The
cage cleaning schedule, air filtration and recirculation, health checks and facility
maintenance were carried out in accordance with the applicable test laboratories’
Standard Operating Procedures, and such activities were recorded in the animal room
records.
Animals were housed and maintained according to the AAALAC International Guide
for the Care and Use of Laboratory Animals, CCAC Guidelines for Care and Use of
Experimental Animals and test laboratories’ Standard Operating Procedures.

Teklad Guinea Pig Diet and water were offered ad libitum throughout the
acclimatization and study periods.

Route:
epicutaneous, semiocclusive
Vehicle:
other: none
Concentration / amount:
induction- 100%
Challenge- 100%
Route:
epicutaneous, semiocclusive
Vehicle:
other: none
Concentration / amount:
induction- 100%
Challenge- 100%
No. of animals per dose:
20- test substance group
10- control (naive)
5- positive control
Details on study design:
Induction Phase

Test Group (20 animals)
The test item was applied to 20 guinea pigs on Day 0 according to the following method.
Approximately 0.48 - 0.5 g portion of the test item was applied to a 2.5 x 2.5 cm gauze patch, moistened with 0.2 mL of WFI, then the patch was applied onto the shaved left flank of each guinea pig, and secured in place occlusively by using 3 M Blenderm Surgical Tape.
The trunk of each guinea pig was then tightly wrapped by using Coban self-adherent wrap and secured at the ends with Zonas Porous Tape for a 6-hour exposure period. After 6 hours, the wrappings, patch and the test item were removed and the skin was cleansed with sterile WFI.
The same procedure was performed on the same test area (cleared of hair) on Day 8, and again on Day 14 after the initial application.

Negative Control Group (10 animals)
A negative control group, consisting of 10 animals was used. During the induction phase, the left flank of each animal was shaved, then a blank 2.5 x 2.5 cm gauze patch was similarly patched to the left flank and secured in place on Day 0, Day 8 and Day 14.

Positive Control Group (5 animals)
The animals in the positive control group were subjected to similar procedures and evaluations on Days 0, 8 and 14 as described for the animals in the test item-treated group with the exception that 0.3% w/v DNCB was substituted as a reference substance.

Challenge Phase
Fourteen days after the last induction application, the test item was applied “as is” in the same manner as during the induction phase, for a 6-hour exposure period on study Day 28, to the closely clipped right flank of each test and negative control animal.
Challenge controls:
The positive control item (0.1% DNCB) was applied to the right flank of each animal in the positive control group for a 6-hour exposure period.
Positive control substance(s):
yes
Remarks:
1-chloro-2,4-dinitrobenzene (DNCB)
Positive control results:
100% (5/5) positive
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none remarkable
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none remarkable.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none remarkable
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none remarkable.
Reading:
1st reading
Hours after challenge:
24
Group:
other: naive
Dose level:
0
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none remarkable
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: other: naive. Dose level: 0. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none remarkable.
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
other: naive
Dose level:
0
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none remarkable
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: naive. Dose level: 0. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none remarkable.
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.3%
No. with + reactions:
5
Total no. in group:
5
Clinical observations:
none remarkable
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. Dose level: 0.3%. No with. + reactions: 5.0. Total no. in groups: 5.0. Clinical observations: none remarkable.
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.3%
No. with + reactions:
5
Total no. in group:
5
Clinical observations:
none remarkable
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 0.3%. No with. + reactions: 5.0. Total no. in groups: 5.0. Clinical observations: none remarkable.

not applicable

Interpretation of results:
GHS criteria not met
Conclusions:
Based on the results, 2-decyltetradecanoic acid was found to be non-sensitizing in a Buehler Skin
Sensitization Study in guinea pigs.
Executive summary:

A skin sensitization study of the test item 2 -decyltetradecanoic acid in guinea pigs was carried out. Three groups of Hartley guinea pigs were used. Twenty animals were in the test group, ten animals in the negative control group and five animals were in the positive control group. The test item was ground to a fine powder then 0.48-0.50 g portions were applied “as is” to 2.5 x 2.5 cm gauze patches and moistened with sterile Water for Injection (WFI). The gauze patches were then topically applied for a 6-hour exposure period to the shaved left flanks of 20 guinea pigs on Days 0, 8 and 14. The applications on Days 0, 8 and 14 represented the induction phase of the study. On Day 28, 14 days after the final induction application, a 2.5 x 2.5 cm gauze patch loaded with the test item is” moistened with WFI, was applied to the shaved right flank of each animal in the test group for a 6-hour exposure period. This application represented the challenge application. A negative control group, consisting of 10 animals was used. During the induction phase (Days 0, 8, and 14) a blank 2.5 x 2.5 cm gauze patch was applied to the left shaved flank of each animal. On Day 28 (Challenge Phase), the test item (“as is”) moistened with WFI, was applied to the shaved right flank of each negative control animal for a 6-hour exposure period. A group of 5 positive control animals was subjected to identical procedures as outlined above for the test group of animals (induction phase), with the exception that the positive control item, 0.3% 1-chloro-2, 4-dinitrobenzene (DNCB), was substituted as a reference substance. During the challenge phase, the positive control item (0.1% DNCB) was applied to the shaved right flank of each positive control animal. An evaluation of skin reaction was carried out and recorded at 24 hours and 48 hours after completion of each application. None of the guinea pigs administered the test item had any signs of local skin irritation after the induction applications or after the challenge period. All 5 of the positive control animals showed a positive response. Based on these findings, the test item 2 -decyltetradecanoic acid was found to be non-sensitizing in a Buehler Skin Sensitization Study in guinea pigs.

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

A skin sensitization study according to OECD 406 of the test item 2 -decyltetradecanoic acid in guinea pigs was carried out. Three groups of Hartley guinea pigs were used. Twenty animals were in the test group, ten animals in the negative control group and five animals were in the positive control group. The test item was ground to a fine powder then 0.48-0.50 g portions were applied “as is” to 2.5 x 2.5 cm gauze patches and moistened with sterile Water for Injection (WFI). The gauze patches were then topically applied for a 6-hour exposure period to the shaved left flanks of 20 guinea pigs on Days 0, 8 and 14. The applications on Days 0, 8 and 14 represented the induction phase of the study. On Day 28, 14 days after the final induction application, a 2.5 x 2.5 cm gauze patch loaded with the test item is” moistened with WFI, was applied to the shaved right flank of each animal in the test group for a 6-hour exposure period. This application represented the challenge application. A negative control group, consisting of 10 animals was used. During the induction phase (Days 0, 8, and 14) a blank 2.5 x 2.5 cm gauze patch was applied to the left shaved flank of each animal. On Day 28 (Challenge Phase), the test item (“as is”) moistened with WFI, was applied to the shaved right flank of each negative control animal for a 6-hour exposure period. A group of 5 positive control animals was subjected to identical procedures as outlined above for the test group of animals (induction phase), with the exception that the positive control item, 0.3% 1-chloro-2, 4-dinitrobenzene (DNCB), was substituted as a reference substance. During the challenge phase, the positive control item (0.1% DNCB) was applied to the shaved right flank of each positive control animal. An evaluation of skin reaction was carried out and recorded at 24 hours and 48 hours after completion of each application. None of the guinea pigs administered the test item had any signs of local skin irritation after the induction applications or after the challenge period. All 5 of the positive control animals showed a positive response. Based on these findings, the reference substance 2 -decyltetradecanoic acid was found to be non-sensitizing in a Buehler Skin Sensitization Study in guinea pigs.

A Local Lymph Node Assay was performed with the source substance 2-butyloctanoic acid on mice according to OECD Guideline 429 and in compliance with GLP.

Three groups of 4 female mice received an open application of 25 µl of test substance onto the dorsum of each ear at concentrations of 10%, 25% or 50%. Another group of 4 females received only the vehicle, acetone:olive oil (4:1, v/v). Treatment was for 3 consecutive days. Three days later each animal received an intravenous injection of 3H-methyl thymidine, and 5 h later the draining lymph nodes were collected and the incorporation of tritiated thymidine assessed by scintillation counting.

On comparing the groups treated with the test substance with the control group, the Stimulation Indices were calculated to be 1.0, 2.6 and 1.7 for 10%, 25% and 50%, respectively. Under the conditions of the study, the test substance was considered not to be a sensitiser in mice.


Migrated from Short description of key information:
The reference substance 2 -decyltetradecanoic acid was found to be non-sensitizing in a Buehler Skin Sensitization Study in guinea pigs.
Supporting a Local Lymph Node Assay was performed with the source substance 2-butyloctanoic acid. Also the source substance was considered not to be a sensitiser in mice.

Justification for selection of skin sensitisation endpoint:
Key study according to OECD 406 with the reference substance, supporting study according to OECD 429 with the source substance 2-butyloctanoicacid showed no sensitising effect.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The Category member 2 -decyltetradecanoic acid is based on the available information on sensitisation not sensitising to the skin and does not require classification according Regulation (EC) No 1272/2008.