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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Remarks:
Data generated by ICCVAM for validation of the LLNA. The protocol utilized may have been different from the currently accepted OECD protocol.

Data source

Reference
Reference Type:
review article or handbook
Title:
Unnamed
Year:
1999

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Principles of method if other than guideline:
The experiment is part of the OECD validation of the murine local lymph node assay.
GLP compliance:
not specified
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Chemical structure
Reference substance name:
Pyridine
EC Number:
203-809-9
EC Name:
Pyridine
Cas Number:
110-86-1
Molecular formula:
C5H5N
IUPAC Name:
pyridine
Details on test material:
Not specifically given, but purity of pyridine for all ICCVAM-NICEATM in vitro studies for validation of alternative methods was > 99.9%

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female

Study design: in vivo (LLNA)

Vehicle:
not specified
No. of animals per dose:
4
Positive control substance(s):
not specified

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
> 3
Test group / Remarks:
Test group 1
Key result
Parameter:
SI
Value:
> 3
Test group / Remarks:
Test group 2
Key result
Parameter:
SI
Value:
> 3
Test group / Remarks:
Test group 3
Key result
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: no data

Any other information on results incl. tables

Pyridine is a very weak allergen in the human predictive test and so the conclusion that pyridine is positive in the LLNA was unexpected. The conclusion that pyridine is a sensitiser is not clear.

Applicant's summary and conclusion

Interpretation of results:
other: ambiguous
Conclusions:
The EC50 of pyridine in the LLNA is greater than 3; however, this is unexpected as pyridine was a very weak allergen in the human predictive test.
Executive summary:

Pyridine was tested by the U.S. National Institute of Environmental Health Sciences in their validation studies of the murine Local Lymph Node Assay (LLNA). Few details are available on the doses or methods used. The EC50 of pyridine in the LLNA is greater than 3; however, this is unexpected as pyridine was a very weak allergen in the human predictive test.