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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The test was conducted by a laboratory that was not GLP accredited.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1978
Report Date:
1978

Materials and methods

Principles of method if other than guideline:
Groups of 6 guinea pigs per induction concentration received open test material applications daily for 3 weeks. The vehicle was ethanol/acetone. Challenge applications at 1% were made days 21 and 35. Reactions were assessed 24 and 48 hours after application.
GLP compliance:
no
Type of study:
open epicutaneous test
Justification for non-LLNA method:
Currently no LLNA study is available for assessment. The open epicutaneous test has been carried out as an animal test to predict human sensitization for over a decade and is recommended by international test guidelines such as OECD.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Fixolide

In vivo test system

Test animals

Species:
guinea pig
Strain:
not specified
Sex:
female

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
other: ethanol/acetone (equal parts)
Concentration / amount:
Induction: 0.1 ml of 30%, 10% or 3% AHTN dissolved in a ethanol:acetone (1:1) mixture was applied daily for three weeks on the clipped flank skin with an area of 8cm2.
Challenge: 0.025ml of 3%, 1% or 0.3% AHTN dissolved in a ethanol:acetone (1:1) mixture was applied on day 21 and day 35.
Challengeopen allclose all
Route:
epicutaneous, open
Vehicle:
other: ethanol/acetone (equal parts)
Concentration / amount:
Induction: 0.1 ml of 30%, 10% or 3% AHTN dissolved in a ethanol:acetone (1:1) mixture was applied daily for three weeks on the clipped flank skin with an area of 8cm2.
Challenge: 0.025ml of 3%, 1% or 0.3% AHTN dissolved in a ethanol:acetone (1:1) mixture was applied on day 21 and day 35.
No. of animals per dose:
6 animals
Details on study design:
30%, 10% and 3% AHTN dissolved in equal parts of ethanol and acetone, were used for skin irritation and induction of allergic sensitization test. The minimal irritant and maximal non-irritant concentrations were determined. All animals (including the controls) were challenged at day 21 and rechallenged at day 35. The test material is considered allergenic if the score is at least 1 out of 6 animals showing a positive response with the non-irritating concentrations used for the challenge. Scores were read 24 and 48 hours after the applications.
Challenge controls:
2 control groups of each 6 animals; an untreated and a vehicle treated control group. Control groups were not induced, but they were challenged on day 21 and rechallenged on day 35.
Positive control substance(s):
no

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
All
No. with + reactions:
0
Total no. in group:
6
Clinical observations:
None
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
All
No. with + reactions:
0
Total no. in group:
6
Clinical observations:
None
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
No. with + reactions:
0
Total no. in group:
6
Clinical observations:
None
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
No. with + reactions:
0
Total no. in group:
6
Clinical observations:
None
Remarks on result:
no indication of skin sensitisation
Reading:
other: 1st and 2nd reading after 24 and 48h correspondingly
Group:
positive control
Remarks on result:
not measured/tested
Remarks:
Not tested

Any other information on results incl. tables

Repeated applications during the induction produced moderate to strong skin irritation. Therefore, the first application site had to be changed after a 2 weeks' treatment.

The 1% solution of AHTN caused no primary irritant skin reactions in the control animals. Challenge tests with the highest non-irritant solution of AHTN (1%) on days 21 and 35 were negative for all the induction concentration groups.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
AHTN applied at 30% in an ethanol:acetone (1:1) mixture daily over three weeks at a concentration up to 30%, does not cause allergic contact dermatitis.
Executive summary:

AHTN concentrations of 3, 10 or 30% in ethanol:acetone (50:50) mixtures were applied in 0.1ml doses to 8 cm2 clipped flank skin of 6 guinea pigs per dose. These concentrations were irritating under the conditions used, hence the application site was changed after two weeks during the induction phase. The maximal non-irritating dose was 1%. At the challenge and re-challenge stage two weeks later, the non-irritating dose was applied to a 2 cm2 naïve site. Reactions were read 24 and 48 hours after each challenge dose, and compared to reactions in non-induced control animals. No sensitisation reactions were observed.