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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
430-010-4
EC Name:
-
Cas Number:
12160-44-0
Molecular formula:
K2Fe22O34
IUPAC Name:
hydrate iron potassium hydride
Details on test material:
- Name of test material (as cited in study report):Potassium ferrite
- Physical state: Reddish brown powder
- Composition of test material, percentage of components: K2Fe22O34: 83,8%, K2Fe10O16: 6.2%, K2CO3 1.5H2O: 10.0%
- Lot/batch No.: 23388-17 CG20X 407448A
- Expiration date of the lot/batch: 6 August 1997
- Storage condition of test material: Room temperature, dark, desiccated

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: D. Hall Newchurch. Staffordshire, England.
- Age at study initiation: approximately four to five weeks
- Weight at study initiation: 280-363 grams
- Housing: In groups of five in suspended metal cages with wire mesh floors
- Diet: vitamin C enriched guinea-pig diet FD2 was available ad libitum
- Water: drinking water was available ad libitum
- Acclimation period: six days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.5-21
- Humidity (%): 39-54
- Air changes (per hr): approximately 15
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
water
Remarks:
for irrigation
Concentration / amount:
MAIN STUDY:
- Induction; intradermal injections: 0.25% w/v in water for irrigation
- Induction; topical application: 7.5% w/v in distilled water
- Topical challenge: 7.5 and 3.75% w/v in distilled water
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Remarks:
for irrigation
Concentration / amount:
MAIN STUDY:
- Induction; intradermal injections: 0.25% w/v in water for irrigation
- Induction; topical application: 7.5% w/v in distilled water
- Topical challenge: 7.5 and 3.75% w/v in distilled water
No. of animals per dose:
Number of animals in test group: 20
Number of animals in negative control group: 10
Details on study design:
RANGE FINDING TESTS:
- The intradermal and topical irritancy of a range of dilutions of the test substance was investigated to identify where possible (a) concentrations of the test substance that would produce irritation suitable for the induction phase of the main study and (b) a maximum non-irritant concentration by the topical route of administration for the challenge phase. Animals for these investigations were pre-treated with an intradermal injection of Freund's complete adjuvant 50:50 with water for irrigation, approximately one week prior to the start of the preliminary investigations.
- Selection of concentrations of test substance for the main study: Based on the results of the preliminary investigations, the following concentrations of Potassium ferrite were selected: Induction intradermal injection: 0.25% w/v in water for irrigation. This was the highest concentration that caused irritation but did not adversely affect the animals. Induction topical application: 10% w/v in distilled water. This was the highest concentration that produced some irritation but did not adversely affect the animals. Topical challenge: 7.5 and 3.75% w/v in distilled water. From preliminary investigations 7.5% w/v in distilled water was the highest concentration not giving rise to irritating effects.
MAIN STUDY
A. INDUCTION EXPOSURE:
- Intradermal injections: A 40 x 60 mm area of dorsal skin on the scapular region of the guinea-pig was clipped free of hair with electric clippers. Three pairs of intradermal injections were made into a 20 x 40 mm area within the clipped area. Injectables for the test animals were prepared as follows:
1. Freund's complete adjuvant was diluted with an equal volume of water for irrigation (Ph.Eur); 2. Potassium ferrite, 0.25% w/v in water for irrigation; 3. Potassium ferrite, 0.25% w/v in a 50 : 50 mixture of Freund's complete adjuvant and water for irrigation.
- Topical application: One week after the injections, the same 40 x 60 mm area was clipped and shaved free of hair. A 20 x 40 mm patch of Whatman paper was saturated with approximately 0.4 ml of Potassium ferrite, 7.5% w/v in distilled water. The patch was placed on the skin of the test animals and covered with occlusive dressing. The dressing was left in place for 48 hours.
- During the induction phase, the control animals were treated similarly to the test animals with the exception that the test substance was omitted from the intradermal injections and topical application.
B. CHALLENGE EXPOSURE
- The control and test animals were challenged topically two weeks after the topical induction application using Potassium ferrite, 7.5 and 3.75% w/v in distilled water. Hair was removed by clipping and then shaving from an area on the left flank of each guinea-pig. A 20 x 20 mm patch of Whatman paper was saturated with approximately 0.2 mL of Potassium ferrite, 7.5% w/v in distilled water and applied to an anterior site on the flank. Potassium ferrite 3.75% w/v in distilled water was applied in a similar manner to a posterior site. The patches were sealed to the flank for 24 hours.
Challenge controls:
The control animals were treated as described above.
Positive control substance(s):
yes
Remarks:
Thc sensitivity of the guinea-pig strain used is checked periodically with known sensitisers hexyl cinnamic aldehyde (HCA), benzocaine and mercaptobenzothiazole (MBT).

Results and discussion

Positive control results:
Positive results were obtained in the positive control.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
7.5 %
No. with + reactions:
5
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 7.5 %. No with. + reactions: 5.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
7.5 %
No. with + reactions:
8
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 7.5 %. No with. + reactions: 8.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
3.75%
No. with + reactions:
7
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 3.75%. No with. + reactions: 7.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
3.75%
No. with + reactions:
5
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 3.75%. No with. + reactions: 5.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. No with. + reactions: 0.0. Total no. in groups: 10.0.

Any other information on results incl. tables

CLINICAL SIGNS: No signs of ill health or toxicity were recorded.

BODYWEIGHT: Bodyweight increases were recorded for all guinea-pigs over the period of the study

INDUCTION:

Intradermal injections: Necrosis was recorded at sites receiving Freund's Complete Adjuvant in test and control animals. Slight irritation was seen in test animals at sites receiving Potassium ferrite, 0.25% w/v in water for irrigation and no irritation was observed in control animals receiving water for irrigation.

Topical application: Slight erythema was observed in test animals following topical application with Potassium ferrite 10% w/v in distilled water. Slight erythema was seen in the control guinea-pigs.

CHALLENGE: Marked dermal reactions were seen in nine of the twenty test animals compared to none in the controls, therefore these nine animals gave positive responses. No dermal reactions were seen for eight test animals. Therefore these gave negative responses.The remaining three animals gave inconclusive responses.

Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information