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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
Not reported
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Secondary literature source (documentation insufficient for assessment).
Justification for data waiving:
other:
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
review article or handbook
Title:
Final report on safety assessment of oleic acid, lauric acid, palmitic acid, myristic acid and stearic acid.
Author:
Cosmetic Ingredient Review (CIR) panel
Year:
1987
Bibliographic source:
J. Am. Coll. Tox. 6(3):321- 401

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Magnusson B and Kligman AM, 1969. The guinea pig maximization test
Principles of method if other than guideline:
Not applicable
GLP compliance:
not specified
Type of study:
guinea pig maximisation test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Stearic acid

In vivo test system

Test animals

Species:
guinea pig
Strain:
not specified
Sex:
female
Details on test animals and environmental conditions:
Not reported

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
propylene glycol
Concentration / amount:
50% formulation containing 3.5% stearic acid
100% formulation containing 3.5% stearic acid
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
propylene glycol
Concentration / amount:
50% formulation containing 3.5% stearic acid
100% formulation containing 3.5% stearic acid
No. of animals per dose:
10
Details on study design:
MAIN STUDY

A. INDUCTION EXPOSURE
- No. of exposures: Three
- Exposure period: 3 wk
- Test groups: One
- Control group: Received following injections:
Site 1: 50% aqueous Freund complete adjuvant
Site 2: Propylene glycol
Site 3: A 1:1 preparation of propylene glycol and 50% Freund complete adjuvant
- Site: Upper back
- Frequency of applications: One injection at start of the induction periodfollowed 1 wk later by a topical booster
- Concentrations:
Site 1: 50% aqueous Freund complete adjuvant
Site 2: 50% formulation containing 3.5% stearic acid, in propylene glycol
Site 3: 50% formulation containing 3.5% stearic acid, in 50% aqueous Freund adjuvant
Topical booster: Slight irritating concentration of the formulation in petrolatum

B. CHALLENGE EXPOSURE
- No. of exposures: Three
- Test groups: One
- Control group: One
- Concentrations: The test group and the control group were treated with 50% or 100% of the formulation (3.5% stearic acid)
- Evaluation (hr after challenge): Sites were scored 48h and 72h after start of the challenge

OTHER: A topical application of 10% sodium lauryl sulfate in petrolatum was made 24h before the topical booster if the formulation was not sufficiently irritating.
The challenge patches were applied occlusively.
Positive control substance(s):
not specified

Study design: in vivo (LLNA)

Concentration:
Not applicable
No. of animals per dose:
Not applicable
Details on study design:
Not applicable
Statistics:
Not applicable

Results and discussion

Positive control results:
Two control guinea pigs died and 4 of the remaining 8 sites challenged with the 100% formulation patch had minimal faint erythema and desquamation was observed at another site after 72h.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
5
Total no. in group:
10
Clinical observations:
Minimal faint erythema
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 5.0. Total no. in groups: 10.0. Clinical observations: Minimal faint erythema.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
1
Total no. in group:
10
Clinical observations:
Mild erythema
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 1.0. Total no. in groups: 10.0. Clinical observations: Mild erythema.
Reading:
2nd reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
3
Total no. in group:
10
Clinical observations:
Faint erythema
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 3.0. Total no. in groups: 10.0. Clinical observations: Faint erythema.
Reading:
2nd reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
2
Total no. in group:
10
Clinical observations:
Desquamation
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 2.0. Total no. in groups: 10.0. Clinical observations: Desquamation.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
1
Total no. in group:
10
Clinical observations:
Faint erythema
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 10.0. Clinical observations: Faint erythema.
Reading:
2nd reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
1
Total no. in group:
10
Clinical observations:
Visible erythema
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 10.0. Clinical observations: Visible erythema.
Reading:
other: No data
Hours after challenge:
24
Group:
positive control
Dose level:
100%
No. with + reactions:
2
Total no. in group:
10
Clinical observations:
Died
Remarks on result:
other: Reading: other: No data. . Hours after challenge: 24.0. Group: positive control. Dose level: 100%. No with. + reactions: 2.0. Total no. in groups: 10.0. Clinical observations: Died.
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
100%
No. with + reactions:
4
Total no. in group:
10
Clinical observations:
Minimal faint erythema
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. Dose level: 100%. No with. + reactions: 4.0. Total no. in groups: 10.0. Clinical observations: Minimal faint erythema.

Any other information on results incl. tables

Five of 10 treatment sites had minimal erythema, and 1 of 10 sites had mild erythema 48h after challenge with the 100% concentration. There were 3 sites with minimal erythema after 72h, 2 of which had signs of desquamation. Other treatment sites had no signs of sensitization.

Challenge of the treatment sites with 50% formulation resulted in minimal erythema at 1 of 10 sites after 48h, which was visible after 72h. All other treatment sites challenged with 50% concentration had no signs of sensitisation.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Under the conditions of the study, and taking into account the limited amount of information available, it appears that the test substance was not sensitizing to skin.
Executive summary:

A maximization study was conducted in guinea pig according to Magnusson-Kligman (1969) to evaluate the allergic contact sensitization potential of stearic acid.

A cosmetic product containing 3.5% stearic acid was tested at the concentrations 50% and 100% on 10 female guinea pigs.

Induction exposure:

Intradermal injections was made on 3 sites, along the upper backs, as follows:

Site 1: 50% aqueous Freund complete adjuvant

Site 2: 50% formulation containing 3.5% stearic acid, in propylene glycol

Site 3: 50% formulation containing 3.5% stearic acid, in 50% aqueous Freund adjuvant

A topical booster with slight irritating concentration of the formulation in petrolatum was applied 1 wk after start of the induction.

A group of guinea pigs served as a control and received following injections:

Site 1: 50% aqueous Freund complete adjuvant

Site 2: Propylene glycol

Site 3: A 1:1 preparation of propylene glycol and 50% Freund complete adjuvant

Challenge:

Two weeks after the topical booster, the test group and the control was treated with 50% or 100% of the formulation.

Sites were scored 48h and 72h later.

Under the conditions of the study, and taking into account the limited amount of information available, it appears that the test substance was not sensitizing to skin.