Trisodium bis[3-[[1-(anilinocarbonyl)-2-oxopropyl]azo]-5-chloro-2-hydroxybenzenesulphonato(3-)]cobaltate(3-)

Endpoint summary

Description of key information

Sensitising

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

From August 30 to September 30, 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

read-across from supporting substance (structural analogue or surrogate)

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

Justification for non-LLNA method:

A LLNA study has not been conducted because adequate data from guinea pig Maximisation test study are already available.

Species:

guinea pig

Strain:

Pirbright-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source:CIBA-GEIGY Limited Animal Production
- Age at study initiation: no data
- Weight at study initiation: Males 367.6 g, Female to 376.3 g
- Housing:The animals were housed individually in Macrolon cages (Type 3), assigned to the different groups by means of random numbers generated by the random number generator
- Diet: ad libitum standard guinea pig pellets - NAFAG No. 845
- Water: fresh water
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):22 ± 3 °C
- Humidity (%): 30 to 70%
- Photoperiod (hrs dark / hrs light): 12 hours cycle dark/light

Route:

intradermal and epicutaneous

Vehicle:

other: Injection: physiological saline, epidermal application: vaseline

Concentration / amount:

INDUCTION
FIRST
Test group:
- adjuvant/saline mixture 1:1 (v/v)
- 5 % of the test item in physiological saline (w/v)
- 5 % of the test item in the adjuvant/saline mixture (w/v)
Control group:
- adjuvant/saline mixture 1:1 (v/v)
- adjuvant/saline mixture 1:1 (v/v)
- physiological saline
SECOND
Test group:
- 50 % of the test item (0.4 g per patch) in vaseline
Control group:
- vaseline only

CHALLENGE
Test and control group:
- 50 % of the test item (0.2 g per patch) in vaseline
Control group:
- vaseline only

Route:

epicutaneous, occlusive

Vehicle:

other: Injection: physiological saline, epidermal application: vaseline

Concentration / amount:

Test and control group:
- 50 % of the test item (0.2 g per patch) in vaseline
Control group:
- vaseline only

No. of animals per dose:

The test was performed on 10 male and 10 female guinea pigs in the test group and 5 males and 5 females in the control group.

Details on study design:

PRETEST:
Intradermal Induction
The concentration for the intradermal injections was selected on account of the solubility of the test article in standard vehicles and its local and systemic tolerability in a pretest.
The following concentration of test article has been used for intradermal injection:
5 % in physiological saline (w/v).
Since 5 % of the test item in physiological saline could be injected and was well tolerated, this concentration was used for the intradermal induction.
Epidermal Applications (induction and challenge)
The concentrations for the epidermal applications were selected on account of the primary irritation potential of the test article. The following concentrations of the test item have been examined on separate animals for the determination of the maximum subirritant concentration:
30 and 50 % in vaseline.
50 % in vaseline was the highest applicable concentration of the test article.
The tested concentrations did not induce erythema reactions.

MAIN STUDY
The induction was a two-stage operation. First, intradermal injections (into the neck region); second, closed patch exposure over the injection sites one week later.

A. INDUCTION EXPOSURE
FIRST INDUCTION
Three pairs of intradermal injections (0.1 ml per injection) were made simultaneously into the left and right side of the shaved neck of the test and control group animals.
- No. of exposures: Three pairs of intradermal injections
- Exposure period: first week
- Test groups: 10 males and 10 females
- Control group: 5 males and 5 females
- Site: shaved neck
- Concentrations:
Test group:
adjuvant/saline mixture 1:1 (v/v)
5 % of the test item in physiological saline (w/v)
5 % of the test item in the adjuvant/saline mixture (w/v)
Control group:
adjuvant/saline mixture 1:1 (v/v)
adjuvant/saline mixture 1:1 (v/v)
physiological saline

SECOND INDUCTION:
The application site of all animals was pretreated with 10% sodium-laurylsulfate (open application) 24 hours prior to the epidermal induction application.
In the test group the test item was incorporated in vaseline (w/w) and applied on a filterpaper patch to the neck of the animals (patch 2x4 cm; approx. 0.4 g per patch; occluded administration for 48 hours).

- No. of exposures: one application
- Exposure period: second week
- Test groups:10 males and 10 females
- Control group:5 males and 5 females
- Site:shaved neck
- Concentrations:
Test group:
0.4 g of Acid Yellow 151 within vaseline
Control group:
vaseline only

B. CHALLENGE EXPOSURE
The test and control group animals were tested on one flank with the test item in vaseline (w/w) and on the other flank with the vehicle alone (patch 2x2 cm; approx. 0.2 g per patch; occluded administration for 24 hours).
- No. of exposures:
- Day(s) of challenge: Fifth week
- Exposure period:24 hours
- Test groups:10 males and 10 females
- Control group:5 males and 5 females
- Site: flank
Test
0.2 g per patch of the test item in vaseline
control group
vaseline only
- Evaluation (hr after challenge):
Twenty four and forty eight hours after removing the dressings, the challenge reactions were graded according to the Draize scoring scale

OTHER:
After the intradermal and the epidermal induction application skin irritation is normally induced by the adjuvant, the high test article concentration, or the sodium lauryl sulfate pretreatment. Because most of the reactions are treatment related and not test article related ,the reactions are
generally not described in the results section.

Positive control substance(s):

not required

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

2 mg/L

No. with + reactions:

20

Total no. in group:

20

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 2 mg/L. No with. + reactions: 20.0. Total no. in groups: 20.0.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

2 mg/L

No. with + reactions:

20

Total no. in group:

20

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 2 mg/L. No with. + reactions: 20.0. Total no. in groups: 20.0.

Under the experimental conditions employed, 100 % of the animals of the test group showed skin reactions 24 and 48 hours after removing the dressings. The test item is, therefore, classified as an extreme sensitizer in albino guinea pigs according to the grading of Magnusson and Kligman.

Score 24 hours after removal of the dressing

Male animals	156	157	158	159	160	161	162	163	164	165
Erythema score:	2	1	2	2	2	2	2	2	2	2
Edema score:	2	1	2	1	2	1	2	2	1	2
Female animals	171	172	173	174	175	176	177	178	179	180
Erythema score:	2	2	2	2	22	2	1	1	1	2
Edema score:	1	2	1	1	2	2	1	1	1	2

Score 48 hours after removal of the dressing

Male animals	156	157	158	159	160	161	162	163	164	165
Erythema score:	2	1	2	2	2S	2	2	2	2	2
Edema score:	2	2	2	1	3	2	2	2	2	2
Female animals	171	172	173	174	175	176	177	178	179	180
Erythema score:	2	2	2S	2	2S	2S	1	1	1	2S
Edema score:	2	2	3	2	3	3	2	2	2	3

S= scaling

Interpretation of results:

other: Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

Skin sensitising

Executive summary:

The test item has been tested according to the OECD 406 (Guinea pig maximisation test).

Under the experimental conditions employed, all the animals of the test group showed skin reactions 24 and 48 hours after removing the dressings.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to CLP Regulation (EC 1272/2008), a substance has to be classified as Skin sensitiser Sub-category 1B if during a Guinea pig maximisation test the animals with a positive response are:

≥ 30 % to < 60 % responding at > 0,1 % to ≤ 1 % intradermal induction dose or

≥ 30 % responding at > 1 % intradermal induction dose

During the test 100 % of the animals showed a reaction (first intradermal induction 5 %, second intradermal induction 50 %), therefore the test substance is classified as skin sensitizing Sub-category 1B according to the CLP Regulation (EC 1272/2008).