2-(1,3-dihydro-3-oxo-2H-indol-2-ylidene)-1,2-dihydro-3H-indol-3-one

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 1982 to May 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No GLP study, oxidized form of the test item, acceptable, well-documented study report which meets basic scientific principles

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Principles of method if other than guideline:

Method as requested by the National Institute of Environmental Health Sciences, USA

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-(1,3-dihydro-3-oxo-2H-indol-2-ylidene)-1,2-dihydro-3H-indol-3-one

EC Number:

207-586-9

EC Name:

2-(1,3-dihydro-3-oxo-2H-indol-2-ylidene)-1,2-dihydro-3H-indol-3-one

Cas Number:

482-89-3

Molecular formula:

C16H10N2O2

IUPAC Name:

2-(1,3-dihydro-3-oxo-2H-indol-2-ylidene)-1,2-dihydro-3H-indol-3-one

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): CI Vat Blue #1: Indigo
- Substance type: active substance
- Physical state: blue solid
- Analytical purity: essentially pure
- Lot/batch No. unlabeled: #A1A Eastman Kodak
- Purity test date: 19. October 1981
- Lot/batch No. labeled: 1555-105 New England Nuclear
- Radiochemical purity (if radiolabelling): ca. 70%
- Specific activity (if radiolabelling): 13.4 mCi/mmol
- Radioactivity: 5.88 mCi
- Locations of the label (if radiolabelling): [phenyl-14C(U)]-

Radiolabelling:

yes

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Kingston, NY
- Age at study initiation: adult
- Housing: singly
- Individual metabolism cages: yes
- Diet: Purina Rat Chow ad libitum
- Water: furnished water ad libitum
- Acclimation period: at least 2 weeks

Administration / exposure

Type of coverage:

occlusive

Vehicle:

other: 1. ointment from PEG 1540+PEG 400+propylene glycol; 2. unchanged

Duration of exposure:

168 and 192 hours

Doses:

Dermal 1: 3.7 mg/kg bw
Dermal 2: 1.5 mg/kg bw

No. of animals per group:

3

Control animals:

no

Details on study design:

Dose selection as requested by NIEHS

DOSE PREPARATION / APPLICATION
Dermal 1:
Vehicle: ointment
Composition: 9 g PEG 1540, 6 g PEG 400, 3 g propylene glycol
Concentration: 28 mg ointment + 2 mg labeled indigo (2.53 x 10E8 DPM)
Dosage: 1 cm² ointment: 3.7 mg/kg bw

Dermal 2:
applied as dry powder: 0.5 mg (6.3 x 10E7 DPM)
Dosage: 1 cm² dry powder: 1.5 mg/kg bw

TEST SITE
- Preparation of test site: clipping of fur on the back 20 to 24 hours prior treatment
- Area of exposure: 1 cm²
- Type of cover / wrap if used: occlusive hardback waxed paper + adhesive tape
- Time intervals for shavings or clipplings: 20 to 24 hours

SITE PROTECTION / USE OF RESTRAINERS FOR PREVENTING INGESTION: yes: occlusive hardback waxed paper + adhesive tape glued to the animals' skin covered with elastic bandage also glued to the animals' skin

SAMPLE COLLECTION
- Tissues and body fluids sampled: urine, faeces, blood (plasma and red blood cells), selected tissues (see attached table)
- Time and frequency of sampling: see attached tables
- Time of sacrifice:
- Dermal 1: 192 hours
- Dermal 2: 1 rat - 168 hours; 2 rats - 192 hours

SAMPLE PREPARATION
- Preparation details: dermal 1: 28 mg ointment (9 g PEG 1540, 6 g PEG 400, 3 g propylene glycol) were molten at 40°C, 2 mg 14C-indigo were added and mixed with spatula
dermal 2: applied unchanged as dry powder

ANALYSIS
- Method type(s) for identification: Liquid scintillation counting; HPLC/scintillation spectrometry

Results and discussion

Signs and symptoms of toxicity:

no effects

Dermal irritation:

no effects

Absorption in different matrices:

see attached table

Total recovery:

dermal 1: 92.4% +/- 4.2%
dermal 2: 75.2% +/- 3.4%

Percutaneous absorption

Percutaneous absorption 1

Dose:

1.18 mg/cm²

Parameter:

percentage

Absorption:

2 %

Remarks on result:

other: 0-72 h

Remarks:

dermal 1: 3.7 mg/kg in ointment

Percutaneous absorption 2

Dose:

0.42 mg/cm²

Parameter:

percentage

Absorption:

0.7 %

Remarks on result:

other: 0-72 h

Remarks:

dermal 2: 1.5 mg/kg dry powder

Conversion factor human vs. animal skin:

no data

Any other information on results incl. tables

NA

Applicant's summary and conclusion

Conclusions:

Very low dermal absorption of indigo. Excretion via urine > feces. Only about 2% of indigo was excreted unchanged..
No potential for bioaccumulation of indigo or its metabolites was observed.

Executive summary:

The toxicokinetic properties of Indigo has been investigated in male rats (Research Triangle Institute: Absorption,
Distribution, Metabolism and Excretion of CI Vat Blue#I; Indigo; RTI/2227/00-04P, September 1983). For this purpose, radioactive labeled (14C) Indigo (radiochemical purity ca. 70 %) was administered as a single intravenous injection (0.23 mg/kg bw), a single oral gavage (3.0; 31; 305 mg/kg bw) and a single dermal application (1.5 and 3.7 mg/kg bw).

The higherst tissue levels after oral administration were found in liver and kidneys

Dermal administration: After dermal application of the ointment, 0.8% of the administered radioactivity were found in urine, feces and cage washes; after application of the dry powder, only 0.3% were found, leading to a very limited dermal absorption of indigo.

There were no hints for a possible bioaccumulation of indigo