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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
August 1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1982
Report date:
1982

Materials and methods

Principles of method if other than guideline:
Method: other: variation of Magnusson and Kligman method
GLP compliance:
no
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
An LLNA study was not performed because there is an existing reliable study for skin sensitisation using the Guinea Pig Maximisation test method.

Test material

Constituent 1
Chemical structure
Reference substance name:
Etidronic acid
EC Number:
220-552-8
EC Name:
Etidronic acid
Cas Number:
2809-21-4
Molecular formula:
C2H8O7P2
IUPAC Name:
(1-hydroxyethylidene)bisphosphonic acid
Test material form:
not specified

In vivo test system

Test animals

Species:
guinea pig
Strain:
Pirbright-Hartley
Sex:
female

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
other: water, Freund's Adjuvant (intradermal induction) and Vaseline (topical induction and challenge)
Concentration / amount:
5% induction, 25% challenge
Challenge
Route:
epicutaneous, semiocclusive
Vehicle:
other: water, Freund's Adjuvant (intradermal induction) and Vaseline (topical induction and challenge)
Concentration / amount:
5% induction, 25% challenge
No. of animals per dose:
20 test and 20 controls
Details on study design:
1st application: Induction 5 % intracutaneous
2nd application: Induction 5 % occlusive epicutaneous
3rd application: Challenge 25 % semiocclusive

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
No. with + reactions:
8
Total no. in group:
20
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
No. with + reactions:
5
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation

Any other information on results incl. tables

TEST SUBSTANCE GROUP RESPONSES
24 hours: 8 animals (erythema: grade 1 - slight redness)
48 hours: 5 animals (erythema: grade 1 - slight redness)
72 hours: 0 animals displaying symptoms

CONTROL GROUP RESPONSES
24 hours: 6 animals (erythema: grade 1 - slight redness)
48 hours: 2 animals (erythema: grade 1 - slight redness)
72 hours: 0 animals displaying symptoms

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In a guinea-pig maximisation study (reliability score 2), not conducted to GLP, sodium salt of HEDP was not sensitising to the skin.