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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
20 Oct - 19 Nov 2004
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP-study, which meets national standard methods, tested with the source substance AgSil TM 25 Potassium Silicate Solution. According to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Version / remarks:
2003
Deviations:
yes
Remarks:
only historical positive control, one dose tested
GLP compliance:
yes
Remarks:
Product Safety Laboratories
Type of study:
Buehler test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): AgSil TM 25 Potassium Silicate Solution
- Physical state: claer to hazy white, thick liquid
- Composition of test material, percentage of components: 70% water, 30% silicic acid, potassium salt, potassium silicate
- Lot/batch No.: C052804K1
- Stability under test conditions: stable for the duration of testing
- Storage condition of test material: at room temperature
- Other: ratio: 2.47, pH: 11.3

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: Hartley albino
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Elm Hill Breeding Labs, Chelmsford, MA, USA
- Age at study initiation: young adult
- Weight at study initiation: 310 - 418 g
- Housing: group housing in stainless steel cages with mesh floors
- Diet (e.g. ad libitum): pelleted Purina guinea pig chow #5025
- Water (e.g. ad libitum): filtered tap water was supplied ad libitum by an automatic water dispensing system
- Acclimation period: 3, 6 or 40 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 - 22
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 20 Oct To: 19 Nov 2004

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
Induction: 100% (undiluted)
Challenge: 75%
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
Induction: 100% (undiluted)
Challenge: 75%
No. of animals per dose:
20 in test group and 10 in naive control group
Details on study design:
RANGE FINDING TESTS:
Test to determine the highest non-irrritating concentration of the test substance to be used as challenge dose. The test substance was applied neat (100%) and diluted with distilled water to yield concentrations of 75, 50 and 25% (w/w) to the clipped test side (dorsal area and trunk) using an occlusive Hill Top Chamber. The sites were wrapped with Durapore adhesive tape. After 6h exposure the chambers were gently removed and the test sites were gently cleansed (identical to main study). Approximately 24 h after application, each site was evaluated for local irritation reactions.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 h
- Test group: near test substance (0.4 mL)
- Control group: no treatment
- Site: left side of each animal
- Frequency of applications: once a week
- Duration: Days 0 - 21
- Concentration: 100%


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 28
- Exposure period: 6 h
- Test group: test substance in distilled water (0.4 mL)
- Control group: test substance in distilled water (0.4 mL)
- Site: right side of each animal
- Concentrations: 75%
- Evaluation (hr after challenge): 24 and 48 h after the challenge application


OTHER: Scoring system
0 - no reaction
0.5 - very faint erythema, usually non-confluent (very faint erythema is not considered a positive reaction)
1 - faint erythema, usually confluent
2 - moderate erythema
3 - severe erythema with or without edema
Positive control substance(s):
yes
Remarks:
technical alpha-hexylcinnamaldehyde (historical control)

Results and discussion

Positive control results:
The first and the second reading of the historical positive control group gave 6/10 animals with positive reactions whereas the corresponding negative control group (5 animals) gave no reactions at both time points.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
other: challenge control
Dose level:
75%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
very faint erythema in 4/10 animals
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: other: challenge control. Dose level: 75%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: very faint erythema in 4/10 animals.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
75%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
very faint erythema in 8/20 animals
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 75%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: very faint erythema in 8/20 animals.
Reading:
2nd reading
Hours after challenge:
48
Group:
other: challenge control
Dose level:
75%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
animals were free of irritation
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: challenge control. Dose level: 75%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: animals were free of irritation.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
75%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
one animal with very faint erythema
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 75%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: one animal with very faint erythema.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
CLP: not classified
DSD: not classified