1,3'-Bipyridinium, 5'-[[4-[[4-[(1',2'-dihydro-6'-hydroxy-3,4'-dimethyl-2'-oxo[1,3'-bipyridinium]-5'-yl)azo]benzoyl]amino]phenyl]azo]-1',2'-dihydro-6'-hydroxy-3,4'-dimethyl-2'-oxo-, salt with 2-hydroxypropanoic acid (1:2)

Endpoint summary

Description of key information

Not skin 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:

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

Adequacy of study:

key study

Study period:

From March 11th to April 18th, 1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Justification for type of information:

Justification for Read Across is detailed in the IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

adopted May 12, 1981

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Study already available.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Kleintierfarm Madoerin AG
- Age at study initiation: 8 - 9 weeks
- Weight at study initiation: males 367 - 434 g, females 315 - 484 g.
- Housing: individually in Makrolon type-3 cages with standand softwood bedding.
- Die: pelleted standand Kliba 342, Batch 28/86 guinea pig breeding/maintenance diet ("KIiba", KIingentaImuehIe AG), ad Iibitum.
- Water: community tap water from Itingen, ad libitum.
- Acclimation period: one week under test condition after veterinary examination.

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 3 °C
- Humidit: 40 - 70 %
- Air changes: 10 - 15 air changes per hour.
- Photoperiod: 12 hours artificial fluorescent light / 12 hours dark.
- Other: music / light period.

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

0.1 %

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Concentration / amount:

25 %

Day(s)/duration:

2 days

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Concentration / amount:

25 %

Day(s)/duration:

1 day

No.:

#2

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Concentration / amount:

25 %

Day(s)/duration:

1 day

No. of animals per dose:

Control vehicle group: 5 males and 5 females
Test item and control groups: 10 males and 10 females

Details on study design:

RANGE FINDING TESTS
The objective of the investigation was to identify irritant test article concentrations suitable for the induction phase of the main study. In addition, a suitable non-irritant concentration of the test article, by the topical route of administration, was identified for the challenge application.

Intradermal injection
- Amount: 0.1 mI/site
- No of animals: 2 per group.
- Concentrations: 5, 3, 1, 0.5 and 0.1 % of the test article in physiological saline.
- Observations: 24 hours after application.

Topical application
- Concentrations: 25, 10, 5 and 3 % of the test article in physioIogical saline.
- Application: the patches were covered by a strip of aluminum foil and firmly secured by elastic plaster wrapped around the trunk and covered with impervious adhesive tape.
- Dressing removal: after an exposure period of 24 hours.
- Reaction assessmet: the reaction sites were assessed for erythema and edema on a numerical basis. Further examination of the sites were performed 24 and 48 hours after removal of thg dressings.

MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal injection
- Exposure area: an area of dorsal skin from the scapular region (approx. 6 × 8) was clipped free of hair.
- Injections: 3 pairs of intradermal injections, 0.1 mI/site.
a) Freunds' complete adjuvant 50:50 with physiological saline for injection
b) the test article, diluted to 0.1 %, with physiological saline
c) the test article at the concentration 0.1 %, emulsified in a 50:50 mixure of Freunds' complete adjuvant and physiological saline for injection.

Topical application
- Time after injection: 1 week.
- Application area: 4 × 4 cm patch satured by test solution.
- Concentration: test item at 25 %
- Dressing coverage: the patch was covered by aluminum foil and firmly secured by an elastic plaster wapped around the trunk of the animal and secured with impervious adhesive tape.
- Exposure duration: the dressings were left in place for approximately 48 hours.
- Control group: the guinea-pigs of the control group received identical treatment without the test article.

B. CHALLENGE EXPOSURE
- Days after induction: two weeks after induction.
- Application area: 5 × 5 cm, covered by 2 × 2 cm patch satured by test solution.
- Concentration: test item at 25 %
- Exposure duration: the dressings were removed after 24 hours.
- Control group: the guinea-pigs of the control group were treated with vehicle only.

RE-CHALLENGE
- Days after challenge: two weeks after challenge.
- Concentration: test item at 25 %

OBSERVATIONS
- Mortlity / Viability: once daily.
- Body weights: at pre-treatment start, start of application and end of test.
- Toxic symptoms: daily.

Positive control substance(s):

yes

Remarks:

1-chlor-2,4-dinitro-benzol (DNCB)

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

25 %

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none different from the control

Remarks on result:

no indication of skin sensitisation

Reading:

rechallenge

Hours after challenge:

48

Group:

test chemical

Dose level:

25 %

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none different from the control

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

-

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no positive reactions were evident

Reading:

rechallenge

Hours after challenge:

48

Group:

negative control

Dose level:

-

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

animals showed erythema and a yellowish discolored application area

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

-

No. with + reactions:

9

Total no. in group:

15

Remarks on result:

positive indication of skin sensitisation

All animals showed erythema and a yellowish discoulored application area after the first and second challenge.

No death occurred.

The animals of the test article treated group showed the sarne reactions as described for the control one.

No systemic symptoms were observed.

The body weight gain of all animals was not affected during the test procedure.

NEGATIVE CONTROL

No positive reactions were evident in the animals after first challenge application, whereas the animals showed erythema and a yellowish discolored application area after second challenge application.

Application area around the injection site of series 1 and 3 were found to show erythema and edema in the animals of the control group from day 2 to 6. Starting with day 7 to 9 of test, crusts were observed, and exfoliation was observed from day 10 to 16; additional crusts were observed from day 17 until termination of test.

POSITIVE CONTROL

According to the result observed, DNCB possess a strong skin sensitizing (contast allergenic) potential in the guinea pig strain used (Dunkin-Hartley albino guinea pigs).

Interpretation of results:

other: not classified, according to the CLP Regulation (EC 1272/2008)

Conclusions:

Not skin sensitising

Executive summary:

The skin sensitization study was performed to assess the allergenic potential of the test item, when administered to albino guinea pigs. The test was conducted in accordance with OECD guideline 406. The induction was performed by intradermal injection at 0.1 % of test item and by topical application of test material at 25 %. A first challenge was performed 2 weeks after induction, administrating test item at 25 % by topical application; a second challenge was then performed.

According to the procedures followed in the experiment, no difference between the test group and the vehicle-treated controls were evident after epidermal challenge application of test item. Therefore, the substance is considered to possess no skin sensitizing potential in albino guidea pigs.

After the second challenge application no positive results were observed in the animals of the test article treated group: at 24 hours reading resulted to be 0 %, as well as at 48 hours.

No toxic symptoms were evident in the guinea pigs of either the control nor test group. No death occurred.

Conclusion

Not skin sensitizer; no response were observed.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There are no information about the skin sensitization potential of Basic Orange 064, thus the available information on the structural analogue Similar Substance 02 have been taken into consideration; the read across approach can be considered as appropriate and suitable to assess the property under investigation (details about the approach are reported into the IUCLID section 13).

The skin sensitization study was performed to assess the allergenic potential of the Similar Substance 02, when administered to albino guinea pigs. The test was conducted in accordance with the OECD guideline 406. The induction was performed by intradermal injection at 0.1 % of test item and by topical application of test material at 25 %. A first challenge was performed 2 weeks after induction, administrating test item at 25 % by topical application; a second challenge was then performed. No difference between the test group and the vehicle-treated controls were evident after epidermal challenge application of test item. Therefore, the substance is considered to possess no skin sensitizing potential in albino guidea pigs. Aften the challenge application no positive results were observed in the animals of the test article treated group: at 24 hours reading response resulted to be 0 %, as well as at 48 hours.

No toxic symptoms were evident in the guinea pigs of either the control nor test group. No death occurred.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 3.4.2.2 skin sensitisation section, skin sensitizer means a substance that will lead to an allergic response following skin contact.

Available experimental evidences reported no animals with reactions responding to an intradermal induction dose of 0.1 %; thus, the substance does not meet the criteria to be classified as skin sensitizer, according to the CLP Regulation (EC 1272/2008).