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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:
January 2003 - April 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to standard protocols and under GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
guinea pig maximisation test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Sodium chlorate (supplier: ATOFINA)
- Molecular formula (if other than submission substance): NaClO3
- Molecular weight (if other than submission substance): 106.45
- Physical state: yellow orange-colored granules
- Analytical purity: 99.68%
- Impurities (identity and concentrations): H2O (0.022%), NaCl (0.017%), Ca3(PO4)2 (0.12%), Fe2O3 (0.16%)
- Composition of test material, percentage of components: NaClO3 (99.68%), H2O (0.022%), NaCl (0.017%), Ca3(PO4)2 (0.12%), Fe2O3 (0.16%)
- Purity test date: October 3, 2002
- Lot/batch No.: 1E0121UM
- Expiration date of the lot/batch: October 2003
- Storage condition of test material: in dark (protect from light) and at room temperature
- Other: date of receipt: November 30, 2002

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, L'Arbresle, France
- Age at study initiation: on day 1 the animals of the main test were 1-2 months old
- Weight at study initiation: on day 1 (weight±SD): males 391±20 g, females 383±17 g
- Housing: housed individually in polycarbonate cages with stainless steel lid equipped with a polypropylene bottle
- Diet (e.g. ad libitum): 106 pelleted diet (UAR, Villemoisson, Epinay-sur-Orge, France), free access
- Water (e.g. ad libitum): ad lib
- Acclimation period: at least 5 days before the beginning of the study


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 30 - 70
- Air changes (per hr): approximately 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12h/12h


IN-LIFE DATES: From: ? To: ?

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
physiological saline
Concentration / amount:
Induction: 25% (w/w)
Challenge: 25% (w/w)
Rechallenge: 10% (w/w)
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
physiological saline
Concentration / amount:
Induction: 25% (w/w)
Challenge: 25% (w/w)
Rechallenge: 10% (w/w)
No. of animals per dose:
- Main test: 30 animals (15 males and 15 females)
In control group: 10 animals (5 males and 5 females)
In treated group: 20 animals (10 males and 10 females)
- Preliminary test: 3 males and 3 females
Details on study design:
RANGE FINDING TESTS:
- By intradermal route tested concentrations: 25%, 10%, 5%, 1% and 0.1% (w/w) (0.1 mL injected).
- By cutaneous route: Induction phase tested concentration: 25% (w/w) and Challenge phase tested concentrations: 25% and 10% (w/w)

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures:
Intradermal injection: Based on the results of a preliminary study. Six injections were made deep into the dermis of a 4 cm x 2 cm clipped interscapular area, on day 1. Three injections of 0.1 mL were made into each side of this interscapular region (i.e. three pairs of sites), as follows:
1 Anterior
FCA at 50% (v/v) in 0.9% NaCl (Treated group)
FCA at 50% (v/v) in 0.9% NaCl (Control group)
2 Middle
test item at 1% (w/w) in 0.9% NaCl (Treated group)
0.9% NaCl (Control group)
3 Posterior*
test item at 1% (w/w) in the mixture FCA/0.9% NaCl (50/50) (Treated group)
vehicle at 50% (w/v) in a mixture FCA/0.9% NaCl (50/50) (Control group)
Topical application: On day 8, a pad of filter paper (approximately 8 cm2) was fully-loaded with the test item at the concentration of 25% (w/w) and was then applied to the interscapular region of the animals of the treated group. The control group was exposed to the vehicle.
- Exposure period: topical application 48 h
- Test groups: test compound
- Control group: vehicle (NaCl)
- Site: Interscapular region
- Frequency of applications: 7 days after the intradermal injection the sites were treated with the test sample for 48 h
- Duration: from injection till topical applacation was 7 days
- Concentrations: 1% intracutaneous and 25% occlusive epicutaneous

B. CHALLENGE EXPOSURE
- No. of exposures:
Topical application: On day 22, all animals of both groups were challenged by a cutaneous application of the test item to the right flank. The test item was maintained under an occlusive dressing for 24 hours. The vehicle was applied to the left flank under the same experimental conditions.
- Day(s) of challenge: 24 h (3 weeks after the first intradermal injection)
- Exposure period: 24 h
- Test groups: test compound
- Control group: test compound
- Site: posterior flank
- Concentrations: 25 % occlusive epicutaneous (25% (w/w) in 0.9% NaCl)
- Evaluation (hr after challenge): evaluated approximately 24 and 48 hours after removal of the dressing
Grading system:
- no visible change 0
- discrete or patchy erythema 1
- moderate and confluent erythema 2
- intense erythema 3

OTHER: C. RECHALLENGE
As equivocal cutaneous reactions were noted, a second challenge application was performed on day 36. The test item at the concentration of 10% (w/w) in 0.9% NaCl was applied to the left flank and the vehicle to the right flank of animals of both groups, under the same experimental conditions as for the first challenge application.
Challenge controls:
Yes, treated with test substance.
Positive control substance(s):
yes
Remarks:
Mercaptobenzothiazole at the concentration of 20% (w/w).

Results and discussion

Positive control results:
According to the magnusson and Kligman method, positive control test item Mercaptobenzothiazole at the concentration of 20% (w/w) induced positive skin sensitization reactions in 80% (8/10) guinea pigs.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
25% (w/w)
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
2 animals: dryness
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25% (w/w). No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: 2 animals: dryness.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
25% (w/w)
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
4 animals: dryness. Remark: motivation for 1 '+' animals see table below.
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25% (w/w). No with. + reactions: 1.0. Total no. in groups: 20.0. Clinical observations: 4 animals: dryness. Remark: motivation for 1 '+' animals see table below..
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25% (w/w)
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 25% (w/w). No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25% (w/w)
No. with + reactions:
2
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 25% (w/w). No with. + reactions: 2.0. Total no. in groups: 10.0.
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
10% (w/w)
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: 10% (w/w). No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
10% (w/w)
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: 10% (w/w). No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
10% (w/w)
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: negative control. Dose level: 10% (w/w). No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
10% (w/w)
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: negative control. Dose level: 10% (w/w). No with. + reactions: 0.0. Total no. in groups: 10.0.

Any other information on results incl. tables

In the control group 2 animals were tested positive. So the animals with a scoring of '1' in the treated group are equivocal and therefore not evaluated as a positive reaction. See table below.

FIRST CHALLENGE

Scoring at 24h

Conc. 25%(w/w)

Scoring at 48h

Conc. 25%(w/w)

+ or ± or -

Controls

31 M

0

0

-

32 M

0

0

-

33 M

0

0

-

34 M

0

0

-

35 M

0

0

-

46 F

0

0

-

47 F

0

1

-

48 F

0

0

-

49 F

0

0

-

50 F

0

1

-

Treated group

36 M

0

0

-

37 M

0

0

-

38 M

0

0

-

39 M

0

0

-

40 M

0

1

±

41 M

1/S

2/S

+

42 M

0

0

-

43 M

0

0

-

44 M

0

0

-

45 M

1

1/S

±

51 F

0

0

-

52 F

0

0

-

53 F

0

0

-

54 F

0

0

-

55 F

0

0

-

56 F

1/S

0/S

±

57 F

0

0

-

58 F

0

0

-

59 F

0

0

-

60 F

0

0/S

?

S = dryness of the skin

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
At 24 h respectively 48 h after rechallenge, neither by the test nor by the control animals, primary skin irritations or a reference to a sensitive effect could be established. The test substance sodium chlorate should not be classified as sensitizing to the skin.
Executive summary:

A Guinea Pig Maximisation test was conducted with a test group of 20 Hartley guinea pigs and a negative control group of 10 Hartley guinea pigs. They were used to investigate the skin sensitising properties of the test compound. The study was performed in accordance with the method of B. Magnusson and A. M Kligman (OECD-guidelines: Guideline 406 ‘Skin Sensitisation’). The study was designed and performed according to Good Laboratory Practice Standards.

The test group received first intradermal injections with 1% test substance. After 7 days a topical application of SLS in vaseline was performed. Ans on Day 8 the animals were treated with a 48 h occluded epicutaneous applications of 25% (w/w) in 0.9% NaCl. Two weeks after the last application, the test animals received a similar 24 h epicutaneous application. After 24 h and 48 h skin reactions were scored. Controls were treated with vehicle during induction and 25% (w/w) during challenge.

No systemic clinical signs and no deaths were noted during the study.

After the first challenge application, a discrete erythema was recorded in 2/10 animals of the control group at the 48-hour reading. According to the study report a discrete or moderate erythema was noted on one or two flanks of 5/20 animals of the treated group, at the 24 and/or 48-hour readings. However, as the control group shows positive skin reactions, the actual positive skin reaction count is 1/20 animals in the treated group. After rechallenge, no cutaneous reactions were observed.

At 24 h respectively 48 h after rechallenge, neither by the test nor by the control animals, primary skin irritations or a reference to a sensitive effect could be established. The test substance sodium chlorate should not be classified as sensitizing to the skin.