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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
Study period:
From 1994-01-12 to 1994-02-19
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study performed according to OECD test guideline No. 406 and in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Version / remarks:
1992
Deviations:
no
Principles of method if other than guideline:
not applicable
GLP compliance:
yes (incl. certificate)
Remarks:
UK GLP compliance programme (inspection date: 1992-10-27)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
At the time of study performance, the LLNA method was not adopted.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Test material form:
liquid
Details on test material:
- Physical state: clear colourless liquid
- Storage condition of test material: in the dark at approximately 4°C

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: D. Hall, Darley Oaks, Burton-on-Trent, Staffordshire, England.
- Age at study initiation: young
- Weight at study initiation: 250-300 g
- Housing: in groups of 5 in stainless steel cages.
- Diet (e.g. ad libitum): antibiotic free diet ad libitum (SQC, FD1 guinea pig diet with added vitamin C produced by Special Diets Services, Witham, Essex).
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days for the animals used for the preliminary study and 19 days for those selected for the main tests.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-24 °C. On 2 occasions the recorded temperature fell by 1 °C below the protocol specified range. These deviations are considered not to have affected the outcome of the study.
- Humidity (%): 28-66 %. On one occasion the relative humidity was recorded to be less than the minimum specified in the protocol. This deviation is considered not to have affected the outcome of the study.
- Air changes (per hr): no data
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: no data

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
other: light liquid paraffin
Concentration / amount:
25 % / 3 x 0.1 mL
Day(s)/duration:
Day 1
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
other: ethanol
Concentration / amount:
100 %
Day(s)/duration:
Day 8 / 48 hours
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: ethanol
Concentration / amount:
100 % and 50% / 24 hours
Day(s)/duration:
Day 22
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
5 preliminary test animals, 20 test animals, 10 control animals
Details on study design:
RANGE FINDING TESTS:
- Intradermal injections: 100%, 50%, 25%, 10%, 5%, and 1% v/v in light liquid paraffin. 1 guinea-pig pre-treated 7 d before with 4 intradermal injections of 1:1 FCA/water. The highest concentration which produced an acceptable localised response at each injection site was 25%.
- Topical induction and challenge: 100%, 50%, 25% and 12.5% v/v in ethanol. 4 guinea-pigs pre-treated with FCA/water as described above. Undiluted test article was found to be non-irritant when applied topically and was therefore selected for the topical induction phase of the main study. Undiluted test article and a 50% v/v concentration of the test article in ethanol were selected for the challenge concentrations.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2, intradermal injections and topical application
- Exposure period: 48h for topical application
- Test groups:
INTRADERMAL: 3 pairs of intradermal injection (0.1 mL) on Day 0 as follows:
- 1/ 50% v/v FCA/distilled water
- 2/ test substance 25% in light liquid paraffin
- 3/ test substance 25% in 50:50 distilled water/FCA
Six days after the intradermal induction, as the undiluted test material was non-irritant, the test area of all test and control animal was treated topically with 0.5 mL of 10 % sodium lauryl sulphate in light liquid paraffin in order to produce irritation.
TOPICAL: 7 days after intradermal injections, the test substance (100%) was applied (patches of Whatman No. 3 filter paper, 4cm x 2cm) and covered with a strip of "Blenderm" surgical tape secured in place and wrapped with "Elastoplast" elastic adhesive bandage (occlusive tape).
- Control group: similarly treated with the exception that the ethanol was topically applied instead of the test substance
- Site: shaved dorsal area between the shoulders

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 14 d after the topical induction application, i.e. 21 d after study initiation
- Exposure period: 24 hours
- Test groups: 100% on the anterior aspect of the left flank, 50% v/v in ethanol on the posterior aspect of the left flank. Similarly treated than topical induction (patches 2cm x 2 cm)
- Control group: similarly treated with the exception that the test substance was omitted
- Site: left flanks
- Concentrations: 100% and 50% v/v in ethanol
- Evaluation (hr after challenge): approximately 24 and 48 hours after patch removal.
Challenge controls:
None
Positive control substance(s):
yes
Remarks:
Benzocaine

Results and discussion

Positive control results:
Ethyl p amino benzoate (Benzocaine) was used as a positive control as this is known to be a mild to moderate sensitiser. The material was administered as a 1 % concentration in propylene glycol for the intradermal injections and a 4 % concentration in acetone for the topical induction. Challenge was conducted at concentrations of 4 % and 3 % in acetone. This positive control study took place during the period from 1993-07-07 to 1993-07-31.
Three animals in the test group gave positive response to 4 % benzocaine resulting in a response incidence of 30 %. Neither challenge concentration elicited a response in any control animal at any of the observation times during the study. These results confirm that benzocaine is a mild to moderate sensitizer under the conditions of this study and the test system is therefore considered to be validated.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100 %
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
grade 1 (discrete or patchy erythema)
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50 %
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
50 %
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0 %
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0 %
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
4 %
No. with + reactions:
3
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation

Any other information on results incl. tables

none

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the test conditions, ST 06 C 93 is not classified as a skin sensitiser.
Executive summary:

In a dermal sensitisation study performed according to the EU test method B.6 and in compliance with GLP, ST 06 C 93 was tested in female Hartley guinea-pigs using the Guinea-Pig Maximisation Test method (20 treated animals + 10 controls).

The preliminary study determined the concentration to be used for the induction and challenge phases of the main study.

 

ST 06 C 93 diluted in light liquid paraffin at 25% (v/v) was administered by injection for intradermal induction. As the substance was not a skin irritant, 24 hours prior to the topical application, the site was pre-treated with 0.5 mL 10% w/w sodium lauryl sulphate in light liquid paraffin. Topical induction was performed with the test material as supplied, 7 days after intradermal injections. For the challenge, 21 days after study initiation, it was tested at 100% and 50 % v/v in ethanol.

 

ST 06 C 93 produces evidence of skin sensitisation in one animal at 100 %, resulting in a response incidence of 5 %.

 

No response was exhibited by any animal of the control group.

 

The historical positive control, benzocaine, produces evidence of skin sensitisation in three of ten animal at 100 %, resulting in a response incidence of 30 %.These results confirmed that benzocaine is a mild to moderate sensitiser under the conditions of this study and the test system was therefore considered to be validated.

 

Under the test conditions, ST 06 C 93 is not classified according to the Regulation EC No. 1272/2008 (CLP) and to the GHS.

This study is considered as acceptable and satisfies the requirement for sensitisation endpoint.