Registration Dossier

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-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
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

Reference
Name:
Unnamed
Type:
Constituent
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 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 absorptionopen allclose all
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
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