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Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Remarks:
Type of sensitisation: skin sensitisation in the guinea pig using Magnusson and Kligman method
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 03 August 2015 to 11 December 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Well documented GLP study performed according to OECD Guideline 406. Variations from the relative humidity were observed during the study. These deviations were considered to have no impact on the animal health or on the outcome of the study and interpretation of the results due to their low magnitude.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report date:
2015

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
yes
Remarks:
variations from relative humidity; no impact on animal health or outcome of the study and interpretation of results
GLP compliance:
yes (incl. QA statement)
Remarks:
22 september 2015
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
An LLNA test has been done showing ambiguous results due to irritation and no conclusion can be drawn. Since the substance is viscous the mice were scratched ears.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid, uncoloured
Details on test material:
- Name of test material (as cited in study report): Rhodiantal original IBCH
- Analytical purity: 100%
See confidential details on test material for more information

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: LAL/HA/BR
Sex:
female
Details on test animals and environmental conditions:
- Source: LAB-ÁLL Bt. Budapest, 1174 Hunyadi u. 7., Hungary
- Justification of strain: The guinea pig is the standard species used for skin sensitisation studies.
- Body weight range at randomisation: 274-305 g
- Age of animals at arrival: young adult, 5 weeks at onset of the treatment
- Acclimatization time: 6 days
- Cage type: animals were housed in macrolon cages size IV (24x56x33.5 cm), with 5 animals/cage to allow socialization
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.1 - 23.0 °C
- Humidity (%): 34 - 79%
- Air changes (per hr): 15-20 air exchange/hour
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
corn oil
Concentration / amount:
100% (control group)
Day(s)/duration:
Day 1
Route:
intradermal
Vehicle:
corn oil
Concentration / amount:
5% w/v in corn oil (test group)
Day(s)/duration:
Day 1
Adequacy of induction:
other: highest concentration used causing no more than mild-to-moderate skin irritation and well tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
100% (control group)
Day(s)/duration:
Day 8 / 48 hours
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
100% (undiluted) (test group)
Day(s)/duration:
Day 8 / 48 hours
Adequacy of induction:
other: highest concentration used causing no more than mild-to-moderate skin irritation and well tolerated systemically
Challengeopen allclose all
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
100% (undiluted) (control group)
Day(s)/duration:
Day 22 / 24 hours
Adequacy of challenge:
highest non-irritant concentration
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
50% (control group)
Day(s)/duration:
Day 22 / 24 hours
Adequacy of challenge:
highest non-irritant concentration
No.:
#3
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
100% (undiluted) (test group)
Day(s)/duration:
Day 22 / 24 hours
Adequacy of challenge:
highest non-irritant concentration
No.:
#4
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
50% (test group)
Day(s)/duration:
Day 22 / 24 hours
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Preliminary test: 8 male animals

Main test:
Intra-dermal induction exposure:
- control group: 5
- test group: 10
Dermal induction exposure:
- control group: 5
- test group: 10
Challenge exposure:
- control group: 5
- test group: 10
Details on study design:
RANGE FINDING TESTS:
Test item concentrations:
- intra-dermal injection: 0.5, 1, 2.5 and 5% (w/v)
- dermal application: 25, 50, 75 and 100% (w/v)
Time of observations for local effects:
- Preliminary study: daily, up to 6 days.
- Intra-dermal induction exposure: 24 hours after treatment.
- Dermal induction exposure: 1, 24, 48 and 72 hours after patch removal.
- Challenge exposure: 24 and 48 hours after patch removal.
Exposure time:
- For the dermal treatment: 48 hours.
Test item application and observations:
- For the intra-dermal application, 0.1 mL per concentration was injected intra-dermally into the hair free skin of the flanks. One concentration was injected on the right side and another concentration on the left side of the animals. Each concentration was injected in duplicate. Two animals were used per concentration.
- For the dermal application, approximately 0.5 mL per concentration was applied onto the clipped and shaved skin of the animals. A closed patch exposure was performed by means of an occlusive bandage using similar treatment procedures as for the main study. One concentration was used on the right side and another concentration on the left side of the animals. Two animals were used per concentration. Time of exposure was 48 hours.

MAIN STUDY
A. Intradermal induction exposure
- Control group: 5 animals
- Test group: 10 animals
Concentration of the test item:
- Control: corn oil
- Test group: 5% (w/v) in corn oil
Day of treatment: 1
Site of treatment: shoulder
Time of observations: 24 hours after the treatment

B. Dermal induction exposure
- Control group: 5 animals
- Test group: 10 animals
Concentration of the test item:
- Control: corn oil
- Test group: 100% (undiluted)
Day of treatment: 8
Site of treatment: shoulder
Duration of exposure: 48 hours
Time of observations: 1, 24, 48 and 72 hours after the patch removal

C. Challenge exposure
- Control group: 5 animals
- Test group: 10 animals
Concentration of the test item:
- Control: 100% (undiluted) and 50% (w/v) in corn oil
- Test group: 100% (undiluted) and 50% (w/v) in corn oil
Day of treatment: 22
Site of treatment: flank
Duration of exposure: 24 hours
Time of observations: 24 and 48 hours after the patch removal
Challenge controls:
As described in details on study design
Positive control substance(s):
yes
Remarks:
2-mercaptobenzothiazole

Results and discussion

Positive control results:
Challenge with reference item 2-mercaptobenzothiazole resulted in a positive response in test animals previously sensitised. The net response values at the 24 and 48 hour observations represented an incidence rate of 100% and 90% and net score values of 1.00 and 0.90 respectively. In the control animals no visible changes were found either at the 24 or 48 hour examinations following challenge with the reference item.
The dermal scores represented discrete erythema (score 1) developed on the skin of sensitised guinea pigs.
On the basis of the results of the reliability check study, the reference item 2-mercaptobenzothiazole was classified as a skin sensitizer. This demonstrated that the experimental procedure and the test system were appropriate.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100% (undiluted)
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no reactions were found
Remarks on result:
other: Reading: 1st reading. Hours after challenge: 24.0. Group: test group. Dose level: 100% (undiluted). No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no reactions were found.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100% (undiluted)
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no reactions were found
Remarks on result:
other: Reading: 2nd reading. Hours after challenge: 48.0. Group: test group. 100% (undiluted). No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no reactions were found.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100% (undiluted)
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no reactions were found
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 100% (undiluted). No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no reactions were found.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100% (undiluted)
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no reactions were found
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 100% (undiluted). No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no reactions were found.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
50% (w/v) in corn oil
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no reactions were found
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
50 % (w/v) in corn oil
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no reactions were found
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
50% (w/v) in corn oil
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no reactions were found
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
50% (w/v) in corn oil
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no reactions were found
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
50%
No. with + reactions:
10
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
50%
No. with + reactions:
9
Total no. in group:
10

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In conclusion, under the conditions of the present assay the test item Rhodiantal original IBCH was shown to have no sensitisation potential and therefore it is classified as a non-sensitizer, according to current EU-regulations.
Executive summary:

A skin sensitisation study was performed in the guinea pig according to the Magnusson-Kligman method, using a maximisation method with Freund's Complete Adjuvant to evaluate the sensitisation potential of test item RHODIANTAL ORIGINAL IBCH. The study was performed according to OECD Guideline No. 406 (adopted in 1992) and in compliance with GLP guidelines.

Based on the results of a preliminary test, ten naive test animals were subjected to sensitisation procedures in a two-stage process, named induction phase: i.e. an intra-dermal treatment and a 48h topical application (dermal treatment under an occlusive dressing). The test item was used at a concentration of 5% (w/v) for intra-dermal injections and at a concentration of 100% (undiluted) for topical sensitisation treatment. Five naive control guinea pigs were simultaneously exposed to corn oil during the sensitisation phase.

Two weeks after the last induction exposure, a challenge dose (at a concentration of 100% (undiluted)) was administered on the left flank of all animals. The right flank area of the animals was treated with 50% dilution of the maximum dermal challenge dose as a safeguard dose (50% (w/v) in corn oil). Challenge was performed by dermal application of the test item. Skin reactions were measured 24 and 48 h after patch removal.

Incidence Rate:

No signs of systemic toxicity were observed in any animal.

During the induction period very slight erythema (score 1) was observed in test animals 1 and 24 hours after the dermal treatment (on Days 10 and 11). No further local skin effects were observed in either the test group or in the control group.

Intensity of Sensitisation Response:

Following challenge with the concentrations of 100% (undiluted) and 50% (w/v) RHODIANTAL ORIGINAL IBCH in corn oil, there were no skin reactions in the test or control animals.

The net response value represented an incidence rate of 0% after a challenge exposure at both 100% (undiluted) and 50% (w/v) RHODIANTAL ORIGINAL IBCH in corn oil.

In conclusion, under the conditions of the present assay the test item RHODIANTAL ORIGINAL IBCH (Batch No.: ZRP15010GD) was shown to have no sensitisation potential and classified as a non-sensitizer, according to current EU-regulations.