Disodium [2,2'-bi-1H-indole]-3,3'-diolate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

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

Adequacy of study:

key study

Study period:

16 January to 19 February 1987

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Guideline study; The test substance is leukoindigo, which is structurally the same as the registered substance. The leucoindigo is precipitated by neutralising of the alkaline leucoindigo solution (Ingigo Küpe) with CO2 and mixed with molasses to prevent the leucoindigo from oxidation to indigo

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Test material

Test material information

Constituent 1

Reference substance name:

Leuco Indigo

IUPAC Name:

Leuco Indigo

Details on test material:

- Name of test material (as cited in study report): Indigo white 50% paste
- Molecular formula (if other than submission substance): C16H12N2O2
- Molecular weight (if other than submission substance): 264.29
- Smiles notation (if other than submission substance): C4=CC=C2C(=C4)C(O)=C(C1=C(O)C3=C(N1)C=CC=C3)N2
- InChl (if other than submission substance): InChI=1S/C16H12N2O2/c19-15-9-5-1-3-7-11(9)17-13(15)14-16(20)10-6-2-4-8-12(10)18-14/h1-8,17-20H
- Structural formula attached as image file (if other than submission substance): see Fig. 1
- Substance type: preparation
- Physical state: black paste
- Lot/batch No.: Mix 39
- Storage condition of test material: room temperature

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: David Hall Ltd., Burton-on-Trent, UK
- Age at study initiation: 9 to 11 weeks
- Weight at study initiation: 292 to 379 g
- Housing: 4/cage
- Diet: guinea pig FD1 diet, Special Diet Services Ltd., Essex, UK ad libitum
- Water: tap water ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-22
- Humidity (%): 45-55
- Air changes (per hr): ca. 15
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 16 January to 19 February 1987

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

water

Induction 2

Concentration / amount:

Intradermal induction: 0.5%
Epicutaneous induction: undiluted as supplied
Epicutaneous challenge: 25%

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

water

Challenge 2

Concentration / amount:

Intradermal induction: 0.5%
Epicutaneous induction: undiluted as supplied
Epicutaneous challenge: 25%

No. of animals per dose:

Control group: 10
Dose group: 20

Details on study design:

RANGE FINDING TESTS:
up tp 2 dose levels for each application were tested in each 1 or 2 guinea pigs

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1 intradermal, 1 dermal
- Exposure period: occlusive dressing: 48 hours
- Test groups: TS in distilled water/FCA or undiluted
- Control group: distilled water/FCA
- Site: shoulder
- Frequency of applications: single
- Intradermal injections: 2 x 3 preparations: 50% FCA, 0.5% TS in distilled water, 0.5% TS in 50% FCA - treatment group
50% FCA, distilled water, 50% FCA - control group
- Dermal application: 0.2-0.3 mL undiluted TS (40x20 mm patch) occlusive for 48 hour

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 22
- Exposure period: 24 hours
- Test groups: TS + water
- Control group: TS + water
- Site: right flank: TS; left flank: water
- Concentrations: 25%
- Evaluation (hr after challenge): 24 and 48 hours

SCORING:
0 - no reaction
1 - scattered mild redness
2 - moderate and diffuse redness
3 - intense redness and swelling

EVALUATION of RESPONSE:

0% - non-sensitizer
> 0-8% - weak sensitizer
>8-28% - mild sensitizer
>28-64% - moderate sensitizer
>64-80% - strong sensitizer
>80-100% - extreme sensitizer

Challenge controls:

intraindividual in TS and control animals

Positive control substance(s):

not specified

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

25%

No. with + reactions:

5

Total no. in group:

19

Clinical observations:

blue staining of skin/hair not preventing erythema assessment

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25%. No with. + reactions: 5.0. Total no. in groups: 19.0. Clinical observations: blue staining of skin/hair not preventing erythema assessment.

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

25%

No. with + reactions:

4

Total no. in group:

19

Clinical observations:

blue staining of skin/hair not preventing erythema assessment

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25%. No with. + reactions: 4.0. Total no. in groups: 19.0. Clinical observations: blue staining of skin/hair not preventing erythema assessment.

Results 3

Reading:

other: 1st and 2nd reading

Hours after challenge:

24

Group:

negative control

Dose level:

25%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

blue staining of skin/hair not preventing erythema assessment

Remarks on result:

other: Reading: other: 1st and 2nd reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: blue staining of skin/hair not preventing erythema assessment.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

Positive skin reactions were found in 5 animals ( 4 x score 1, 1 x score 2) at the 24-hour and in 4 animals (4 x score 1) at the 48-hour assessment.

According to the evaluation system used in this study, the test item was classified as "mild sensitizer". According to the EU evaluation system the test item has no sensitizing properties.