Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study performed to GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

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:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: Liquid

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/CaBkl
Sex:
female
Details on test animals and environmental conditions:
Source: B & K Universal Ltd
Environmental conditions:
Housed individually in suspended solid floor cages.
Temperature: 19-25ºC
Humidity: 30-70%
Acclimitisation period: 5 days
Air changes: 15 per hour
Lighting: 12 hours continuous light and twelve hours darkness
Free access to mains drinking water and food

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, open
Vehicle:
other: Dimethyl formamide
Concentration / amount:
25µl
Challenge
Concentration / amount:
25µl
No. of animals per dose:
Preliminary Screeening test: Two mice
Main test: Four mice per dose
Details on study design:
Preliminary Screening test.
A preliminary screening test was performed using two mice. The mice were treated by daily application of 25µl of the undiluted test material and the test material at a concentration of 50% v/v in dimethyl formamide, to the dorsal surface of each ear for three consecutive days (Days 1, 2 and 3). The mice were observed twice daily on Day 1 and the surviving mouse on Days 2 and 3 and once daily on Days 4, 5 and 6. Any signs of toxicity or excessive local irritation noted during this time period were recorded. The body weight of each mouse was recorded on Day 1 (prior to dosing) and the surviving mouse on Day 6.

Main test
Groups of 4 mice were treated with the test material at concentrations of 10%, 25% or 50% v/v in dimethyl formamide. The preliminary screening test suggested that the test material would not produce systemic toxicity or excessive local irritation at the highest suitable concentration. The mice were treated by daily application of 25µl of the appropriate concentration of the test material to the dorsal surface of each ear for three consecutive days (Days 1, 2 and 3). The test material formulation was administered using an automatic micropipette and spread over the surface of the ear using the tip of the pipette.
A further group of four mice received the vehicle alone in the same manner.
Five days following the first topical application of the test material (Day 6) all mice were injected via the tail vein with 250µl of phosphate buffered saline (PBS) containing 3H-methyl thymidine giving a total of 20 µCi to each mouse.
The mice were observed twice daily on Day 1 and the surviving mouse on Days 2 and 3 and once daily on Days 4, 5 and 6.

Study design: in vivo (LLNA)

Vehicle:
dimethylformamide
No. of animals per dose:
Preliminary test: two mice
Main test: Groups of four mice

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: See results table below
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: See results table below

Any other information on results incl. tables

Concentration (%v/v) in dimethyl formamide

Dpm

Dpm/Node a

Stimulation index (SI)b

Result

Vehicle

4485.95

560.74

N/A

N/A

10

14062.86

1757.86

3.13

Positive

25

15126.04

1890.76

3.37

Positive

50

33415.68

4176.96

7.45

Positive

Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information
Conclusions:
The test material was considered to be a sensitiser under the conditions of the test.
Executive summary:

A GLP study was performed in accordance with OECD 429 to assess the skin sensitisation potential of Inhibitor AHM P500 in the CBA/Ca strain mouse following topical application to the dorsal surface of the ear.

Following a preliminary screening test, three groups, each of four animals, were treated with 50µl (25 µl per ear) of the test material as a solution in dimethyl formamide at concentrations of 10%, 25% or 50% v/v daily for a period of 3 days. A further group of four animals was treated with dimethyl formamide alone.

Five days following the first topical application all mice were injected with a solution of 3H-methyl thymidine (3HTdR). Five hours after administration of3HTdR, all mice were necropsied and the auricular lymph nodes from each group pooled for analysis.

The Stimulation Index (SI), expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group, was determined. Positive results for sensitisation by skin contact were obtained at all test concentrations, therefore the test material is considered to be a sensitiser under the conditions of the test.