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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:
key study
Study period:
17 February 1999 - 2 June 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
1999

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
At the time the test was performed, no guideline was in force. The test was performed in accordance with the standard method at the time.
Principles of method if other than guideline:
The method followed was that described in KIMBER I, HILTON J and WEISENBERGER C (1989) The murine local lymph node assay for identification of contact allergens: a preliminary evaluation of in situ measurement of lymphocyte proliferation Contact Dermatitis 21 215-220 and BASKETTER DA. and SCHOLES E.W. (1992) Comparison of the local lymph node assay with the guinea-pig maximisation test for the detection of a range of contact allergens. Food and Chemical Toxicology 30, 65-69.
GLP compliance:
yes
Remarks:
expiry date of the test item is not indicated
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Stored at room temperature in the dark and at 4 °C in the dark

In vivo test system

Test animals

Species:
mouse
Strain:
CBA/Ca
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan UK Ltd., Oxon, England
- Age at study initiation: 6 - 8 weeks
- Weight at study initiation: 16.5 - 20 g
- Housing: in groups of four mice in plastic cages
- Diet: standard laboratory rodent diet, ad libitum
- Water: drinking water, ad libitum
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.5 -21.5
- Humidity (%): 57 - 60
- Photoperiod (hrs dark / hrs light): 12 / 12

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
50, 25 and 10%w/v
No. of animals per dose:
4
Details on study design:
MAIN STUDY

ANIMAL ASSIGNMENT AND TREATMENT
The mice were allocated without conscious bias to cages within the treatment groups.
- Name of test method: Determination of incorporated 3H-methyl thymidine
- Criteria used to consider a positive response:
The test substance is regarded as a sensitiser if at least one concentration of the chemical results in a three-fold greater increase in 3HTdR incorporation compared to control values.

TREATMENT PREPARATION AND ADMINISTRATION:
The test substance was prepared in AOO (4:1 acetone/olive oil) at the required concentrations freshly on each day of dosing. Groups of four mice were treated at one of three concentrations of the test substance. The mice were treated by daily application of 25 ul of the appropriate concentration of the test substance to the dorsal surface of each ear for three consecutive days. The test substance was applied to the dorsal surface of each ear using an automatic micropipette. The test substance was spread over the entire dorsal surface of the ear using the tip of the pipette. A further group of four mice received the vehicle alone in the same manner.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:
Responses to the positive control substances hexyl cinnamic aldehyde (HCA) and 2-Mercaptobenzothiazole (MBT), in contemporaneous studies demonstrate the reliability and sensitivity of this assay to detect skin sensitisers in this laboratory.

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
1.1
Test group / Remarks:
10%
Key result
Parameter:
SI
Value:
1.3
Test group / Remarks:
25%
Key result
Parameter:
SI
Value:
1.1
Test group / Remarks:
50%

Any other information on results incl. tables

CELLULAR PROLIFERATION DATA

- For the 10 % test substance group the DPM count was 4975. For the 25 % test substance group the DPM count was 5952. For the 50 % test substance group the mean DPM count was 4984. THE DPM count of the control was 4485.

 

DETAILS ON STIMULATION INDEX CALCULATION

- Stimulation index = test/control ratio = the ratio of 3HTdR incorporation into LNC of test nodes relative to that recorded for control nodes

- The test/control ratio of 3 or more was not recorded for any of the concentrations tested. The test item was not considered to have the potential to cause skin sensitisation.

 

EC3 CALCULATION

- An EC3 value of the test item was not calculated.

 

CLINICAL OBSERVATIONS:

- No signs of ill health or toxicity were observed.

BODY WEIGHTS

- Bodyweight increases were recorded for all groups of mice over the period of the study.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met