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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
December 11, 2013 - February 7, 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to an appropriate OECD test guideline and in compliance with GLP.
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
guinea pig maximisation test
Species:
guinea pig
Strain:
other: Crl: HA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River, 97633 Sulzfeld, Germany
- Age at study initiation: approx. 4 weeks
- Weight at study initiation: 300 - 327 g
- Housing: Semi barrier in an air-conditioned room
- Diet (e.g. ad libitum): free access to autoclaved hay and to Altromin 3122 maintenance diet for guinea pigs
- Water (e.g. ad libitum): free access to tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C
- Humidity (%): 55 ± 10 %
- Air changes (per hr): 10 x / hour
- Photoperiod (hrs dark / hrs light): Artificial light, sequence being 12 hours light, 12 hours dark
Route:
intradermal and epicutaneous
Vehicle:
petrolatum
Concentration / amount:
intradermal injection (induction - first stage), 2.5% suspension (w/v) in cottonseed oil
topical application (induction – second stage), 50% suspension (w/w) in vaseline
topical application (challenge), 50% suspension (w/w) in vaseline
Route:
epicutaneous, occlusive
Vehicle:
petrolatum
Concentration / amount:
intradermal injection (induction - first stage), 2.5% suspension (w/v) in cottonseed oil
topical application (induction – second stage), 50% suspension (w/w) in vaseline
topical application (challenge), 50% suspension (w/w) in vaseline
No. of animals per dose:
Number of animals in the test group: 10
Number of animals in the negative-control group: 5
Number of animals in the dose range finding study: 3
Details on study design:
RANGE FINDING TEST:

For the justification of dose levels a preliminary test was performed.
1 animal was treated intradermally with concentrations of 5% and 2.5% of the test item (suspended with cottonseed oil, Sigma, lot no. MKBJ0602V, expiry date: 01/2014).
1 animal was treated topically with concentrations of 50% and 25% of the test item (suspended with vaseline, Euro OTC Pharma, lot no. 1201035-01, expiry date: 04/2015) for 24 hours.
1 animal was treated topically with concentrations of 50% and 25% of the test item (suspended with vaseline, Euro OTC Pharma GmbH, lot no. 1201035-01, expiry date: 04/2015) for 48 hours.

Based on the results of this preliminary test the following concentrations were chosen for the main test:
a concentration of 2.5% for the intradermal induction
a concentration of 50% for the dermal induction
a concentration of 50% for the challenge application

MAIN STUDY
A. Induction: First Stage, Intradermal Injection

Three pairs of intradermal injections of 0.1 mL volume were given in the shoulder region which was cleared of hair by clipping so that one of each pair lies on each side of the midline.

Test Group: Day 0
Injection 1: a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl
Injection 2: a 2.5% concentration of the test item in cottonseed oil
Injection 3: a 2.5% concentration of the test item formulated in a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl

Control Group: Day 0
Injection 1: a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl
Injection 2: 100% cottonseed oil
Injection 3: a 50% (v/v) formulation of cottonseed oil in a 1:1 (v/v) mixture FCA/physiological saline 0.9% NaCl

Injections 1 and 2 were given close to each other and nearest to the head, while injection 3 was given toward the caudal part of the test area.

B. Induction: Second Stage, Topical Application

Test Group and Control Group: Day 6
Approximately twenty-four hours before the topical application the test area was close-clipped.

Test Group: Day 7
The test item was suspended with vaseline at a concentration of 50%. A patch was fully loaded with 0.5 g of the prepared test item. Then it was applied to the test area and held in contact with the help of an occlusive dressing for 48 hours.

Control Group: Day 7
A patch was fully loaded with 0.5 g of vaseline. Then it was applied to the test area and held in contact with the help of an occlusive dressing for 48 hours.

C. Challenge: Topical Application

The flanks of treated and control animals were cleared of hair by close-clipping.

Test Group and Control Group: Day 20
The test item was suspended with vaseline at a concentration of 50%. A patch loaded with 0.5 g of the prepared test item was applied to the left flank of the animals and a patch loaded with 0.5 g of the vehicle to the right flank (intraspecific control). The patches were held in contact with the help of an occlusive dressing for 24 hours. The application area was not rinsed.

D. Observation

Test Group and Control Group
Approximately 21 hours after removing the patch, the challenge area was cleared of hair by the use of a depilatory cream. Approximately 24 and 48 hours after removing the patch the skin reaction was observed and recorded according to the grades shown below. Additionally all animals were observed for signs of toxicity at least once daily during the test period.
Positive control substance(s):
no
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. No with. + reactions: 0.0. Total no. in groups: 5.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. No with. + reactions: 0.0. Total no. in groups: 5.0.

Preliminary Test

1 animal was treated intradermally with concentrations of 5% an 2.5% of the test item (suspended with cottonseed oil).

1 animal was treated topically with concentrations of 50% and 25% of the test item (suspended with vaseline) for 24 hours.

1 animal was treated topically with concentrations of 50% and 25% of the test item (suspended with vaseline) for 48 hours.

Based on the results of this preliminary test, a concentration of 2.5% was chosen for the intradermal application of the main test and a concentration of 50% was selected for the dermal induction. These concentrations caused slight signs of irritation, without leading to

systemic effects. A concentration of 50% was found to be the highest dose which did not cause any signs of irritation after a topical treatment over a period of 24 hours and therefore was chosen for the challenge application in the main test.

Main Test

All animals of both groups survived throughout the test period. Signs of irritation during the induction:

Intradermal Induction I (24-hour reading):

Injection site 1: erythema grade 1 in 5/5 control and 10/10 test animals, oedema grade 1 in 5/5 control and 10/10 test animals.

Injection site 2: erythema grade 1 in 5/5 control and 10/10 test animals, oedema grade 1 in 3/5 control and 1/10 test animals, necrosis Ø 1mm in 1/10 test animals, necrosis Ø 2 mm in 2/10 test animals.

Injection site 3: erythema grade 1 in 5/5 control and 10/10 test animals, oedema grade 1 in 5/5 control and 9/10 test animals, necrosis Ø 1mm in 1/10 test animals, necrosis Ø 2 mm in 2/10 test animals.

Intradermal Induction I (48-hour reading):

Injection site 1: erythema grade 1 in 5/5 control and 10/10 test animals, oedema grade 1 in 5/5 control and 10/10 test animals.

Injection site 2: erythema grade 1 in 5/5 control and 7/10 test animals, oedema grade 1 in 2/5 control and 1/10 test animals, necrosis Ø 1mm in 1/10 test animals, necrosis Ø 2 mm in 2/10 test animals.

Injection site 3: erythema grade 1 in 5/5 control and 10/10 test animals, oedema grade 1 in 5/5 control and 10/10 test animals, necrosis Ø 2mm in 8/10 test animals, necrosis Ø 4 mm in 1/10 test animals.

Dermal Induction II (48-hour exposure, occlusive):

Immediately after removing the patch: erythema grade 1 in 10/10 test animals.

24 hours after removing the patch: erythema grade 1 in 4/10 test animals.

Challenge Exposure (24-hour exposure, occlusive):

Neither erythema nor oedema were observed in any animal at any time of observation.

There was no evidence of sensitisation and the percentage of sensitised animals was 0%.

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the conditions of the present study it can be stated that the test item caused no reactions identified as sensitisation at the tested
concentration.
According to the EC criteria for classification and labelling requirements for dangerous substances and preparations (Guidelines in Commission Directive 2001/59/EC) labelling is not necessary.
According to Commission Regulation (EU) No 286/2011 as well as GHS (Globally Harmonized Classification System) the test item has no obligatory labelling requirement for skin sensitisation and is unclassified.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the available data reaction mass of potassium methylsiliconate should not be classified as sensitising to skin or the respiratory tract according to the criteria of EU Directive 67/548/EEC and Regulation 1272/2008.