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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Remarks:
in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
Data is from peer-reviewed scientific journal

Data source

Reference
Reference Type:
publication
Title:
Application of Sensitive Mouse Lymph Node Assay for Detection of Contact Sensitization
Author:
Yoshiaki Ikarashi et. al.
Year:
1996
Bibliographic source:
JOURNAL OF APPLIED TOXICOLOGY,1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: As mentioned below
Principles of method if other than guideline:
In the SLNA as well as the LLNA, the lymph node cell (LNC) proliferation is measured by incorporation of radioactive (3H) methyl thymidine (3HTdR).
GLP compliance:
not specified
Type of study:
other: sensitive mouse lymph node assay (SLNA)
Justification for non-LLNA method:
No data available

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
-IUPAC Name: Disodium 2-(2,4,5,7-tetraiodo-6-oxido-3-oxoxanthen-9-yl)benzoate
- Molecular formula : C20H6I4Na2O5
- Molecular weight : 879.86 g/mol
- Smiles notation: C12(c3c(Oc4c1cc(c(c4I)[O-])I)c(c(c(c3)I)[O-])I)c1c(cccc1)C(=O)O2.[Na+].[Na+]
- InChl : 1S/C20H8I4O5.2Na/c21-11-5-9-17(13(23)15(11)25)28-18-10(6-12(22)16(26)14(18)24)20(9)8-4-2-1-3-7(8)19(27)29-20;;/h1-6,25-26H;;/q;2*+1/p-2
-Substance type- Organic
- Physical state: Solid (powder)

In vivo test system

Test animals

Species:
mouse
Strain:
Balb/c
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Japan SLC Inc, Shizuoka,Japan
- Age at study initiation: 6-8 weeks old
- Weight at study initiation: No data available
- Housing: No data available
- Diet (e.g. ad libitum): No data available
- Water (e.g. ad libitum): No data available
- Acclimation period: No data available

ENVIRONMENTAL CONDITIONS
- Temperature (°C): No data available
- Humidity (%):No data available
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): No data available

IN-LIFE DATES: From: To: No data available

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal
Vehicle:
other: For intra-dermal injection: saline and For topical injection : Dimethyl sulphoxide
Challenge
Route:
other: Topical application
Vehicle:
other: For intra-dermal injection: saline and For topical injection : Dimethyl sulphoxide
No. of animals per dose:
3 mice
Details on study design:
RANGE FINDING TESTS: No data available

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1
- Exposure period: No data available
- Test groups: 3
- Control group: No detailed data available
- Site: Two sites of the abdominal skin at both sides of the ventral midline
- Frequency of applications: 1
- Duration: 5 days
- Concentrations: 50 µl of test chemical-FCA emulsion; Maximum injection concentration was 2%

B. CHALLENGE EXPOSURE
- No. of exposures: Thrice (on three consecutive days)
- Day(s) of challenge: three consecutive days
- Exposure period: 3 consecutive days
- Test groups: 3
- Control group: No detailed data available - Site: applied to both sides of each ear
- Concentrations: 25 µl of test chemical-FCA emulsion;Topical concentrations for the chemical was selected based on solubility limit to vehicles
- Evaluation (hr after challenge): the day following the last topical application

OTHER: After the topical exposure auricular lymph nodes were excised and pooled for each experimental group. A single cell suspension of LNC was prepared by mechanical disaggregation through a sterile 200-mesh gauge and washed once with Hanks' balanced salt solution. The LNCs were resuspended in RPMI- 1640 culture medium supplemented with 25 mM N-2-hydroxyethylpiperazine-N'- 2-ethanesulphonic acid (HEPES), penicillin, streptomycin and fetal calf serum, and the total LNC number were determined using an automated cell counter. The LNC suspensions (1 x 106 cells) were seeded into 96-well culture plates (five wells per group) and cultured with 0.5 pCi [3H] methyl thymidine (3HTdR) for 24 h at 37°C in a humidified atmosphere of 5% CO, in air. Culture was terminated by a semiautomatic cell harvester, and the 3HTdR incorporation was determined by liquid scintillation counting. The increases in LNC number and 3HTdR incorporation relative to controls were derived for each experimental group and the total lymph node activation induced by the test chemicals was calculated.
Challenge controls:
No data available
Positive control substance(s):
not specified

Results and discussion

Positive control results:
No data available

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
other: induction exposure phase
Hours after challenge:
24
Group:
test group
Dose level:
50 µl
No. with + reactions:
0
Total no. in group:
3
Clinical observations:
non- sensitizing during sensitive mouse lymph node assay (SLNA)
Remarks on result:
other: see Remark
Remarks:
Reading: other: induction exposure phase. . Hours after challenge: 24.0. Group: test group. Dose level: 50 µl . No with. + reactions: 0.0. Total no. in groups: 3.0. Clinical observations: non- sensitizing during sensitive mouse lymph node assay (SLNA) .
Reading:
other: challenge exposure phase
Hours after challenge:
24
Group:
test group
Dose level:
25 µl
No. with + reactions:
0
Total no. in group:
3
Clinical observations:
non- sensitizing during sensitive mouse lymph node assay (SLNA)
Remarks on result:
other: see Remark
Remarks:
Reading: other: challenge exposure phase. . Hours after challenge: 24.0. Group: test group. Dose level: 25 µl . No with. + reactions: 0.0. Total no. in groups: 3.0. Clinical observations: non- sensitizing during sensitive mouse lymph node assay (SLNA) .

Any other information on results incl. tables

CONCENTRATION

Vehicle

0.25 %

Induction phase- Saline

0.5%

Challenge exposure- DMSO

SLNA values

SIn

1.35

SIP

1.15

SItotal

1.55

DMSO = dimethylsulphoxide

SIn= stimulation index of LNC number;

SIP= stimulation index of LNC proliferation;

SItotal= stimulation index of total lymph node response.

Applicant's summary and conclusion

Interpretation of results:
other: Not Sensitizing
Conclusions:
The test material was considered to be not sensitizing to the skin of BALB/c strain mice in the sensitive mouse lymph node assay (SLNA).
Executive summary:

Sensitive mouse lymph node assay skin sensitization assay was performed on female BALB/c strain mice. They were intradermally injected with 50 µl of test chemical –FCA emulsion into two sites of the abdominal skin at both sides of the ventral line. After 5 days 25 µl of test chemical in vehicle was applied to both sides of each ear for three consecutive days.Control mice were treated by intradermal injection of vehicle-FCA emulsion into the abdomen and then after 5 days they were exposed to vehicle alone on the ears for three consecutive days.The increases in LNC number and3HTdR incorporation relative to controls were derived for each experimental group and expressed as SInand SIP, respectively; SI total as obtained from SInx SIP, which indicates the total lymph node activation induced by the test chemical. A chemical was regarded as positive if it showed an SItotalvalue of 3 or more. The SItotalvalue of test chemical was found to be 1.55 at 5% DMSO concentration. Hence,the test chemical was considered to be not sensitizing to the skin of BALB/c strain mice in the sensitive mouse lymph node assay.