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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:
1996-11-25 to 1997-01-05
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

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

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
, adopted 1992-07-17
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
, signed 1996-02-27
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The GPMT was performed in 1997. At this time the initiation of an LLNA was not mandatory and the Magnusson & Kligman the first choice.

Test material

Constituent 1
Reference substance name:
Strontium chloride hexahydrate
EC Number:
600-046-7
Cas Number:
10025-70-4
Molecular formula:
Cl2-Sr.6H2-O
IUPAC Name:
Strontium chloride hexahydrate
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): Strontium chloride-6-hydrate extra pure
- Physical state: White crystalline solid
- Storage condition of test material: Ambient temperature (< 25 °C), under artificial light
No further information on the test material was stated.

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: David Hall Limited, Burton-on-Trent, Staffordshire, UK (Albino Dunkin Hartley guinea pigs)
- Age at study initiation: ~ 8 to 12 weeks old
- Weight at study initiation: 380 to 483 g (The bodyweight of one animal was above the weight range specified in the study protocol (450 g). According to the author of this study report, this deviation was considered not to affect the purpose or integrity of the study.)
- Housing: The animals were housed singly or in pairs in solid-floor polypropylene cages furnished with woodflakes.
- Diet (ad libitum): Guinea Pig FD1 Diet, Special Diets Services Limited, Witham, Essex, UK
- Water (ad libitum): Mains tap water
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19 to 21 °C
- Relative humidity: 41 to 59 %
- Air exchanges: Approximately fifteen changes per hour
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
water
Concentration / amount:
5 %
Day(s)/duration:
24 and 48 h after intradermal injection the degree of erythema was evaluated
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
50 %
Day(s)/duration:
48 h
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challenge
No.:
#10
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
50 % and 25 %
Day(s)/duration:
24 h
Adequacy of challenge:
other: highest non-irritant concentration and one lower concentration
No. of animals per dose:
Main study:
Test group: 10 animals
Control group: 5 animals
Details on study design:
RANGE FINDING TESTS:
The concentrations of test material to be used at each stage of the main study were determined by 'sighting tests' in which groups of guinea pigs were treated with various concentrations of test material. The procedures were as follows:

- Selection of concentration for intradermal induction:
Four concentrations of test material were investigated (1 %, 5 %, 10 % and 25 % w/v in distilled water). A total of four guinea pigs were used, each guinea pig receiving four 0.1 ml injections of only one concentration of test material. The degree of erythema at the injection sites was assessed approximately 24, 48 and 72 hours and 7 days after injection according to the Draize scoring system. The degree of oedema was not evaluated. Any evidence of systemic toxicity was also recorded. The highest concentration that caused only mild to moderate skin irritation, and which was well tolerated systemically, was selected for the intradermal induction stage of the main study.
- Selection of concentration for topical induction:
Two guinea pigs (intradermally injected with Freund's Complete Adjuvant ten days earlier) were treated with four preparations of the test material (50 %, 25 %, 10 % and 5 % w/w in distilled water). Applications were made to the clipped flanks under occlusive dressings for an exposure period of 48 hours. The degree of erythema and oedema was evaluated approx. 1, 24 and 48 hours after dressing removal. The highest concentration producing only mild to moderate dermal irritation was selected for the topical induction stage of the main study.
- Selection of concentration for topical challenge:
Four preparations of the test material (50 %, 25 %, 10 % and 5 % w/w in distilled water) were applied to the clipped flanks of two guinea pigs under occlusive dressings for an exposure period of 24 hours. These guinea pigs did not form part of the main study but had been treated identically to the control animals of the main study, up to Day 15. The degree of erythema and oedema was evaluated approximately 1, 24 and 48 hours after dressing removal. The highest non-irritant concentration of the test material and one lower concentration were selected for the topical challenge stage of the main study.

MAIN STUDY
Two main phases were involved in the main study; a) an induction of a response and b) a challenge of that response. The bodyweight of each animal was recorded at the start and end of the study.
A. INDUCTION EXPOSURE - TEST GROUP
Shortly before treatment on Day 0 the hair was removed from an area approximately 40 mm X 60 mm on the shoulder region of each animal with veterinary clippers. A row of three injections (0.1 ml each) was made on each side of the mid-line. The injections were:
a). Freund's Complete Adjuvant plus distilled water in the ratio 1:1
b) a 5 % w/v solution of the test material in distilled water
c) a 5 % w/v emulsion of the test material in a 1:1 preparation of Freund's Complete Adjuvant plus distilled water.
Approximately 24 and 48 hours after intradermal injection the degree of erythema at the test material injection sites (i.e. injection site b) was evaluated according to the Draize scoring system.
One week later (Day 7), the same area on the shoulder region used previously for intradermal injections was clipped again and treated with a topical application of the test material formulation. A filter paper patch (WHATMAN No. 4: approximate size 40 mm X 20 mm), loaded with the test material formulation (50 % w/v in distilled water) as a thick, even layer was applied to the prepared skin and held in place with a strip of surgical adhesive tape (BLENDERM: approximate size 50 mm X 30 mm) covered with an overlapping length of aluminium foil. The patch and foil were further secured with a strip of elastic adhesive bandage (ELASTOPLAST: approximate size 250 mm X 35 mm) wound in a double layer around the torso of each animal. This occlusive dressing was kept in place for 48-hours.
The degree of erythema and oedema was quantified one and twenty-four hours following removal of the patches using the Draize scoring system.
Any other reactions were also recorded.

B. INDUCTION EXPOSURE - CONTROL GROUP
Intradermal injections were administered using an identical procedure to that used for the test animals, except that the injections were:
a) Freund's Complete Adjuvant plus distilled water in the ratio 1:1
b) distilled water
c) a 50 % w/v formulation distilled water in Freund's Complete Adjuvant/distilled water 1 :1
The topical applications followed the same procedure as for the test animals except that the vehicle alone was applied to the filter paper.
Skin reactions were quantified as for the test animals.

C. CHALLENGE EXPOSURE
Shortly before treatment on Day 21, an area of approximately 50 mm X 70 mm on both flanks of each animal, was clipped free of hair with veterinary clippers.
A square filter paper patch (WHATMAN No.4 approximate size 20 mm X 20 mm), loaded with a thick, even layer of test material at the maximum non-irritant concentration (50 % w/w in distilled water) was applied to the shorn right flank of each animal and was held in place with a strip of surgical adhesive tape (BLENDERM: approximate size 40 mm X 50 mm). To ensure that the maximum non-irritant concentration was used at challenge, the test material at a concentration of 25 % w/w in distilled water was similarly applied to ta skin site on the left shorn flank. The patches were occluded with an overlapping length of aluminium foil and secured with a strip of elastic adhesive bandage (ELSTOPLAST: approximate size 250 mm X 75 mm) wound in a double layer around the torso of each animal.
After 24 hours, the dressing was carefully cut using blunt-tipped scissors, removed and discarded. The challenge sites were swabbed with cotton wool soaked in distilled water to remove residual material.
Prior to the 24 hours observation the flanks were clipped using veterinary clippers to remove regrown hair.

EVALUATION OF SKIN REACTIONS
Approximately 24 and 48 hours after challenge dressing removal, the degree of erythema and oedema was quantified using the Draize scoring system.
Any other reactions were also recorded.
No further information on the study design was stated.
Challenge controls:
Control group: Distilled water
5 animals were used for the control group
Positive control substance(s):
yes

Results and discussion

Positive control results:
see "attached background material"

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
50 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions were noted
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
50 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions were noted.
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions were noted.
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions were noted
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
50 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
50 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25 % w/w of strontium chloride-6-hydrate extra pure
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted
Remarks on result:
no indication of skin sensitisation

Any other information on results incl. tables

Skin reactions observed after intradermal induction:

Very slight erythema was noted at the intradermal induction sites of eight test group animals at the 24 hour observation and in four test group animals at the 48 -hour observation.

Very slight erythema was noted at the intradermal induction sites of three control group animals at the 24 -hour observation. no skin reactions were noted at the intradermal induction sites of control group animals at the 48 hour observation.

Skin reactions observed after topical induction:

Very slight erythema was noted at the induction sites of five test group animals at the 1 -hour observation and persisted in one test group animal at the 24 -hour observation.

No skin reactions were noted at the treatment sites of control group animals at the 1 and 24 -hour observations.

Body weight

Bodyweight gains of guinea pigs in the test group, between Day 0 and Day 24, were comparable to those observed in the control group animals over the same period.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test material, Strontium chloride-6-hydrate extra pure, produced a 0 % (0/10) sensitisation rate. According to the results the test material does not meet classification criteria for regulation (EC) No 1272/2008 and subsequent regulations.