2,2,6,6-tetramethyl-4-substituted-piperidinyl-1-oxy

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

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

Vehicle:

dimethylformamide

Concentration:

10, 25 or 50 %

No. of animals per dose:

Preliminary test: two mice
Main test: Groups of four mice

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.

Parameter:

SI

Value:

3.13

Test group / Remarks:

10 % concentration

Parameter:

SI

Value:

3.37

Test group / Remarks:

25 % concentration

Parameter:

SI

Value:

7.45

Test group / Remarks:

50 % concentration

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

Interpretation of results:

other: Sensitising

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.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Justification for selection of skin sensitisation endpoint:
Single GLP guideline study available

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based upon the above information the substance meets the criteria for classification as set out by both 67/548/EEC and EC Regulation 1272/2008 and should therefore be classified as follows:

R43 - May cause sensitisation by skin contact.

Skin Sens 1 - H317 May cause an allergic skin reaction.