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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:
08 July 2014 - 15 August 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
refer to analogue justification provided in IUCLID section 13

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report Date:
2014

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
1992
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Pentacalcium hydroxide tris(orthophosphate) is an inorganic salt of the alkaline earth metal calcium and orthophosphate. The water solubility of pentacalcium hydroxide tris(orthophosphate) is low (6.57 mg/L). Dermal absorption is therefore anticipated to be low (ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7c: Endpoint specific guidance. Version 2.0, November 2014). Based on the identity/chemical structure and physicochemical properties, testing for skin sensitisation by means of a Local Lymph Node Assay (OECD 429) is considered to be inappropriate, as it may underestimate the skin sensitising potential of the test substance, leading to a false negative result, due to a low dermal absorption and hence low exposure. For this reason, the Guinea Pig Maximization Test, which involves intradermal injection of the test substance for induction thus ensuring exposure beneath the skin surface, is considered to be the most appropriate method for assessing the skin sensitising potential of this particular substance.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles, River, Germany
- Age at study initiation: 4-6 weeks
- Weight at study initiation: 300.9-327.1 g
- Housing: test animals were housed in groups of up to ten
- Diet: commercial feeding mixture (mühle Knull, Rostock, Germany), ad libitum
- Water: tap water (drinking quality, supplemented with 1g/L vitamin C)
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3 °C
- Humidity (%): 30-70
- Air changes (per hr): 16
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
water
Concentration / amount:
0.5%
Day(s)/duration:
7
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
100%
Day(s)/duration:
2
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Challenge
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
100%
Day(s)/duration:
1
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
5 (negative control)
10 (test groups)
Details on study design:
RANGE FINDING TESTS:
The appropriate test material concentrations for intradermal and epicutaneous induction and epicutaneous challenge exposures were determined in preliminary test using 6 additional FCA-treated animals.
For intradermal exposure, animals were given the test material at 5, 2.5, 1 and 0.5% suspensions in water by intradermal injections (0.1 mL). Animals were examined for signs of skin irritation at 24 and 48 h post-injection according to the Magnusson Kligman grading scale.
For topical exposure, animals were treated with the test material at 100, 50 and 25% in distilled water for 24 h under occlusive conditions. Irritation responses were assessed at 24 and 48 h after patch substance removal.
Based on the results of preliminary test (see Table 1), in the main test, 0.5% test material in water and 100% test material moistened with water were selected for intradermal and topical treatment, respectively.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal and epicutaneous, respectively)
- Exposure period: single injection (intradermal) and 48 h (epicutaneous)
- Test groups:
Intradermal (3 pairs of injections, 0.1 mL):
Injection 1: 1:1 mixture (v/v) FCA/water
Injection 2: 0.5% test substance in water
Injection 3: 0.5% test substance in a 1:1 mixture (v/v) FCA/water
- Negative control group:
Intradermal (3 pairs of injections, 0.1 mL)
Injection 1: 1:1 mixture (v/v) FCA/water
Injection 2: water
Injection 3: 1:1 mixture (v/v) FCA/water

Epicutaneous:
- Test group: test substance at 100%
- Negative control: water

- Site: scapular region (intradermal + epicutaneous)
- Frequency of applications: single
- Duration: Days 0-8 (on day 6, one day prior to epicutaneous induction, the shorn skin of all animals in each group was treated with 0.5 mL of 10% sodium lauryl sulphate vaseline, in order to create a local irritation).

B. CHALLENGE EXPOSURE
- No. of exposures: 1 (challenge)
- Day(s) of challenge: 21 (challenge)
- Exposure period: 24 h
- Test groups: 100% test substance moistened with water
- Control group: 100% test substance moistened with water
- Site: flank region
- Concentrations: 100%
- Evaluation (hr after challenge): 48 and 72 h

OTHER:
Positive control substance(s):
yes
Remarks:
hexyl cinnamic acid (CAS No 101-86-0, routinely evaluated every 6 month at challenge concentrations of 55% in vasseline)

Results and discussion

Positive control results:
Hexyl cinnamic acid (at challenge concentration of 55% in vaseline) induced skin sensitisation reactions in 90% of the treated animals.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
induction (intradermal): 0%; induction (epicutaneoues): 0%, challenge 100%
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no visible clinical symptoms over the period of observation
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
induction (intradermal): 0%; induction (epicutaneoues): 0%, challenge 100%
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no visible clinical symptoms over the period of observation
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no visible clinical symptoms over the period of observation
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:
10
Clinical observations:
no visible clinical symptoms over the period of observation
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
55%
No. with + reactions:
9
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
55%
No. with + reactions:
9
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation

Any other information on results incl. tables

Animal weights

Table 3: Individual animal weights (g) at start / test end (test group)

Animal

Test start

Test end

Body weight change

1

305.3

387.4

82.1

2

313.5

379.8

66.3

3

318.7

414.7

96.0

4

309.3

388.8

79.5

5

301.2

399.9

98.7

6

315.7

385.2

69.5

7

304.1

399.4

95.3

8

321.0

422.8

101.8

9

309.8

375.7

65.9

10

309.3

411.5

102.2

 

Individual weight of control group

Table 4: Individual animal weights (g) at test start and at test end (control group)

Animal

Test start

Test end

Body weight change

K1

309.4

383.0

73.6

K2

300.9

376.1

75.2

K3

324.0

396.1

72.1

K4

327.1

408.5

81.4

K5

326.4

398.7

72.3

 

Table 5: Skin reactions of test animals after treatment with the test material

Animal

Numerical grading after

24 h

48 h

1

0

0

2

0

0

3

0

0

4

0

0

5

0

0

6

0

0

7

0

0

8

0

0

9

0

0

10

0

0

 

Table 6: Skin reactions of control animals after treatment with the test material

Animal

Numerical grading after

24h

48h

K1

0

0

K2

0

0

K3

0

0

K4

0

0

K5

0

0

 

Table 7: Skin reactions of animals after challenge treatment with HCA 55 % in vaseline

Animal

Numerical grading after

24 h

48 h

1

1

1

2

0

0

3

1-2

1-2

4

1

1

5

1-2

2

6

1

1

7

1-2

1-2

8

0-1

1

9

1-2

1

10

1

1

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test material did not induce any skin reactions in intradermally and topically induced guinea pigs after challenge treatment. Therefore, the material does not fulfil the criteria for classification according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), and is thus considered to be not skin sensitizing.