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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
From May 25, 2005 to June 13, 2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Test material form:
solid: particulate/powder

In vivo test system

Test animals

Species:
mouse
Strain:
CBA:J
Sex:
female
Details on test animals and environmental conditions:
Source: Jackson Laboratories
Acclimation: 5 days
Number of animals: 37 females (nulliparous and non-pregnant)
Body weight: 16 - 21g
Body weight variation was within +/- 20% of the sex mean.
Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, at least 10 air changes/hour, and a 12-hour light/12-hour dark cycle.
Diet: Fresh PMI (Diet #5001)
Water: free access to tap water.

Study design: in vivo (LLNA)

Vehicle:
other: Ultrapure liquid petrolatum
Concentration:
0, 2.5, 5, 10 and 25% w/w
No. of animals per dose:
5
Details on study design:
The test substance concentrations selected for the main study were based on the results of a pre-screen test. In the main study, four experimental groups of five female CBA/J mice were treated with test substance concentrations of 2.5, 5, 10 or 25% w/w for three consecutive days, by topical application on the ears. Five vehicle control animals were similarly treated, but with the vehicle alone (Liquid petrolatum). A positive control group with a-hexylcinnamaldehyde (HCA - 50%) was also included in the experiment. Five days after the last exposure, all animals were injected with 5-bromo-2'-deoxy-uridine (BrdU) and the draining (auricular) lymph nodes were then isolated and pooled for each animal. Cells were fixed using 70% ethanol and used for the measurement of the cell number and the BrdU determination (percentage of proliferating cells in "S" phase). Flow cytometry was conducted for analysis and stimulation index (SI) was recorded
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
SI

Results and discussion

Positive control results:
The SI value calculated for the positive control was 9.6 and ear swelling was observed in this group.

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
ca. 0.9
Variability:
+/- 0.7
Test group / Remarks:
2.5%
Key result
Parameter:
SI
Value:
ca. 0.9
Variability:
+/- 0.6
Test group / Remarks:
5%
Key result
Parameter:
SI
Value:
ca. 0.7
Variability:
+/- 0.3
Test group / Remarks:
10%
Key result
Parameter:
SI
Value:
ca. 0.3
Variability:
+/- 0.1
Test group / Remarks:
25%
Cellular proliferation data / Observations:
- SI values were similar among the control and test groups and were below 3. Three concentrations (i.e.2.5, 5 and 25%) induced ear swelling.
- No mortality occurred and no clinical signs of systemic toxicity were observed in the animals of the main study. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

Applicant's summary and conclusion

Interpretation of results:
other: not classified based on EU CLP criteria
Conclusions:
Under the study conditions, the test substance was considered to be non-sensitiser to the skin.
Executive summary:

A study was conducted to determine the skin sensitisation potential of the test substance, 'mono- and di- C16 PSE, K+ and H3PO4' (98.5%) according to OECD Guideline 429 and US EPA OPPTS 870.2600 (LLNA), in compliance with GLP. The test substance concentrations selected for the main study were based on the results of a pre-screen test. In the main study, four experimental groups of five female CBA/J mice were treated with test substance concentrations of 2.5, 5, 10 or 25% w/w for three consecutive days, by topical application on the ears. Five vehicle control animals were similarly treated, but with the vehicle alone (Liquid petrolatum). A positive control group with a-hexylcinnamaldehyde (HCA - 50%) was also included in the experiment. Five days after the last exposure, all animals were injected with 5-bromo-2'-deoxy-uridine (BrdU) and the draining (auricular) lymph nodes were then isolated and pooled for each animal. Cells were fixed using 70% ethanol and used for the measurement of the cell number and the BrdU determination (percentage of proliferating cells in "S" phase). Flow cytometry was conducted for analysis and stimulation index (SI) was recorded. Mortality/viability, body weights, clinical signs, ear size and irritation (and other local effects) were recorded as well. SI values were similar among the control and test groups and were below 3. Three concentrations (i.e.2.5, 5 and 25%) induced ear swelling. No mortality occurred and no clinical signs of systemic toxicity were observed in the animals of the main study. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period. Under the study conditions, the test substance was considered to be non-sensitiser to the skin (MBRL, 2005).