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

Endpoint summary

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

29-Mar to 26-Apr-1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD 404 and GLP compliant. The test substance is leucoindigo in NaOH solution forming the mono- or disodium salt

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

Vienna White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Fa. Gaukler; Offenbach
- Age at study initiation: young adult
- Weight at study initiation: 2.4 to 3.3 kg
- Housing: single
- Diet: Kliba Labordiaet 341 ca 130 g/rabbit/day
- Water: tap water ca. 250 mL/rabbit/day
- Acclimation period: at least 1 week


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 24
- Humidity (%): 30 to 70
- Air changes (per hr): -
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: 29-Mar to 26-Apr-1993

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL

Duration of treatment / exposure:

3 minutes and 1 hour

Observation period:

72 hours
Readings at 1, 24, 48, 72 hours after patch removal

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: upper third of back or flanks
- Coverage: 2.5 x 2.5 cm
- Type of wrap if used: semiocclusive (Fixomull stretch)


REMOVAL OF TEST SUBSTANCE
- Washing (if done): with Lutrol and Lutrol:water 1:1
- Time after start of exposure: 3 minutes or 1 hour


SCORING SYSTEM: according to Draize
Erythema and eschar formation
No erythema 0
Very slight erythema (barely perceptible) 1
Well defined erythema 2
Moderate to severe erythema 3
Severe erythema (beet redness) to eschar formation preventing grading of erythema 4

Edema formation
No edema 0
Very slight edema (barely perceptible) 1
Slight edema (edges of area well defined by definite raising) 2
Moderate edema (raised approximately 1 mm) 3
Severe edema (raised more than 1 mm and extending beyond area of exposure) 4

Irritation parameter:

erythema score

Remarks:

3 minutes exposure

Basis:

mean

Time point:

other: 24 to 72 hours

Score:

1.7

Max. score:

4

Reversibility:

not fully reversible within: 72 hours

Irritation parameter:

edema score

Remarks:

3 minutes exposure

Basis:

mean

Time point:

other: 24 to 72 hours

Score:

0.2

Max. score:

4

Reversibility:

not fully reversible within: 72 hours

Irritation parameter:

edema score

Remarks:

1 hour exposure

Basis:

mean

Time point:

other: 24 to 72 hours

Score:

1.6

Max. score:

4

Reversibility:

not reversible

Remarks:

within 72 hours

Remarks on result:

other: study was terminated at 72 hours due to skin necrosis

Irritant / corrosive response data:

visual necroses were observed in all animals 24 or 72 hours after application
Macroscopic examination of necrotic areas revealed superficial focal necrosis in one and full thickness necrosis in two rabbits.

Other effects:

bluish discoloration of application site

3 Minutes Exposure

	Animal	Erythema	Edema	Comments
1 hour	01	NA	0	index for erythema could not be read because of bluish staining by the test substance
	02	1	0	skin stained by test substance
	03	1	0	skin stained by test substance
24 hours	01	2	0	skin stained by test substance
	02	2	1	skin stained by test substance
	03	2	1	skin stained by test substance
48 hours	01	1	0	skin stained by test substance
	02	2	0	skin stained by test substance
	03	2	0	skin stained by test substance
72 hours	01	1	0	skin stained by test substance
	02	1	0	scaling, skin stained by test substance
	03	2	0	scaling, skin stained by test substance
Mean	01	1.3	0.0
	02	1.7	0.3
	03	2.0	0.3
Mean		1.7	0.2

 

1 Hour Exposure

	Animal	Erythema	Edema	Comments
1 hour	01	NA	0	index for erythema could not be read because of bluish staining by the test substance
	02	2	1	hemorrhage,skin stained by test substance
	03	2	1	hemorrhage,skin stained by test substance
24 hours	01	3	2	hemorrhage,skin stained by test substance
	02	NA	2	necrosis, skin stained by test substance
	03	NA	1	necrosis, skin stained by test substance
48 hours	01	3	2	superficial scabbing, skin stained by test substance
	02	NA	2	necrosis, skin stained by test substance
	03	NA	1	necrosis, skin stained by test substance
72 hours	01	2	2	superficial focal necrosis, skin stained by test substance
	02	NA	1	full thickness necrosis, skin stained by test substance
	03	NA	1	full thickness necrosis, skin stained by test substance
Mean	01	2.7	2.0
	02	NA	1.7
	03	NA	1.0
Mean		NA	1.6

For calculation of the means of erythema and edema only the readings of 24, 48 and 72 hours were used

 

The study was discontinued after the 72-hour reading because of severe irritation

Interpretation of results:

corrosive

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the test conditions chosen and considering the findings described, Indigolösung BASF 20% gives indication of severe skin damage after an exposure period of 1 hour. As Indigo itself has proven not to be an irritant, this effect is most likely due to the NaOH content of the preparation.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1973

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: BASF internal standards followed

Principles of method if other than guideline:

BASF internal testing method

GLP compliance:

no

Species:

rabbit

Strain:

not specified

Vehicle:

unchanged (no vehicle)

Controls:

other: talcum

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 mg

Duration of treatment / exposure:

1 hour

Observation period (in vivo):

1, 24, 144 hours

Number of animals or in vitro replicates:

no data

Details on study design:

SCORING SYSTEM:
Erythema and Edema
Ø - no effect
(+) - questionable
+ - mild
++ - moderate
+++ - marked

N - necrosis
Tr - opacity
Na - scar

Irritation parameter:

chemosis score

Remarks:

see details below

Basis:

mean

Time point:

other: 24 h

Remarks on result:

other: Indigo : marked edema

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: 24 h

Remarks on result:

other: Talcum: mild edema

Irritant / corrosive response data:

Indigo: 1 hour: moderate edema; blue TS remains
24 hours: marked edema, discharge; blue TS remains
144 hours: marked edema, moderate opacity, purulent discharge, white conjunctiva/nictitating membranes, encrusted eyelids
Talcum: 1 hour: mild erythema, mild edema
24 hours: mild erythema
24 hours: no effects

Interpretation of results:

highly irritating

Remarks:

Migrated information Criteria used for interpretation of results: not specified

Conclusions:

Indigoküpe 60% Körner may cause severe eye irritation. As Indigo itself proofed not to be irritating this effect is most likely due to the 5% alkali content.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Data on skin and eye irritation studies show that indigo itself is not irritating to rabbit skin and eyes. Studies with a positive outcome regarding skin or eye irritation contained at least 3% NaOH/KOH.

Based on animal data it can be concluded that a NaOH solution of 8% can be considered corrosive for skin. Based on human data concentrations of 0.5–4% were irritating. In 2 different studies a concentration of 0.5% was irritating for only 55 and 61% of the volunteers, respectively and therefore it is assumed that a concentration, which is slightly lower than 0.5%, is the non-irritating concentration.

The available animal data on eye irritation of NaOH revealed small differences in eye irritation levels. The non-irritant level was 0.2-1.0%, while the corrosive concentration was 1.2% or higher than 2%.

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive