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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:
1988-04-19 to 1988-05-13
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restrictions: No positive control (not required by 1981 version of Test Guideline)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report date:
1988

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
(1981)
Deviations:
no
GLP compliance:
no
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
A skin sensitization test according to OECD 406 has already excisted since 1988 and is sufficient for evaluation of the skin sensitisation potential of the test substance.

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2,4(or 2,4,4)-trimethylhexanedinitrile
EC Number:
283-810-9
EC Name:
2,2,4(or 2,4,4)-trimethylhexanedinitrile
Cas Number:
84713-17-7
Molecular formula:
C9H14N2
IUPAC Name:
2,2,4-trimethylhexanedinitrile; 2,4,4-trimethylhexanedinitrile
Test material form:
other: liquid
Details on test material:
2,2,4(or 2,4,4)-Trimethylhexanedinitrile of Hüls AG, purity 95.3 %, main impurity 1-amino-2-cyano-3,3,5(or 3,5,5)-trimethyl-1-cyclopentene (3.6 %)

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS: 
- Strain: Dunkin-Hartley (Bor: DHPW)
- Sex: female
- Source: Winkelmann, Borchen (Germany)
- Weight at study initiation: 322.7 g (mean test); 333.5 g (mean control)
- Diet: ad libitum, special diet for guinea pigs, SSniff G
- Water: ad libitum, tap water
- Acclimation period: 4-8 days
ENVIRONMENTAL CONDITIONS
- Temperature: 20 +/- 1 °C
- Humidity: 60 */- 5 %
- Photoperiod: 12 hours artificial light, 12 hours dark

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
other: corn oil
Concentration / amount:
1st application: Induction 0.5 % intracutaneous
2nd application: Induction 100 % occlusive epicutaneous
3rd application: Challenge 100 % occlusive epicutaneous
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: corn oil
Concentration / amount:
1st application: Induction 0.5 % intracutaneous
2nd application: Induction 100 % occlusive epicutaneous
3rd application: Challenge 100 % occlusive epicutaneous
No. of animals per dose:
20 test
10 control
Details on study design:
ADMINISTRATION/EXPOSURE 
- Induction schedule: injection followed 1 week later by patch treatment  for 48 hours
- Injection details: 0.1 ml each at 6 positions on shoulders:  
 2 x Freund's Complete Adjuvant / deionized water (50:50)   
2 x test substance 0.5 % in corn oil   
2 x test substance 0.5 % in Freund's Complete Adjuvant / corn oil  (50:50)   simultaneous and symmetrical application of each solution   
controls: corn oil instead of test substance
- Challenge schedule: 2 weeks after end of induction, patch treatment for  24 hours
- Concentrations used for challenge: 100 % in filter paper; readings 24  and 48 hours after removal of patch
- Rechallenge: no
- Positive control: no
EXAMINATIONS
- Grading system: possible scores 0 / 1 / 2 / 3       
0 % of animals scored > 0: no sensitization  
1 -  8 % of animals scored > 0: very slight sensitization  
9 - 28 % of animals scored > 0: slight sensitization
29 - 64 % of animals scored > 0: distinct sensitization
65 - 80 % of animals scored > 0: severe sensitization        
81 -100 % of animals scored > 0: extreme sensitization
Challenge controls:
treated with vehicle (corn oil)
Positive control substance(s):
no

Results and discussion

Positive control results:
No positive control substance used in this study

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no reactions
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100 %. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no reactions.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no reactions
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 100 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no reactions.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no reactions
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100 %. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no reactions.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no reactions
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 100 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no reactions.

Any other information on results incl. tables

RESULTS OF TEST
- Sensitization reaction: 
  0/20 animals positive at 24 hours and at 48 hours = no sensitization
  no animals positive in control group
- Clinical signs: 
  1st induction, FCA application sites: distinct erythema and edema,  necrosis
  1st induction, vehicle + test substance application sites: slight  erythema and edema
  1st induction, vehicle application sites: slight erythema and edema
  2nd induction, test group and control group: inflammation of all FCA  injection sites, eschar formation within 24 hours
- Other: Mean body weight gain 130.5 g in test group, 137.4 g in control  group = expected range

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Classification: not sensitizing
Executive summary:

The skin sensitizing properties of the test item were determined in a guinea pig maximization test according to OECD TG 406 (positive controls not required by 1981 guideline version). Twenty female guinea pigs were intradermally injected with a 0.5 % concentration of test item (in corn oil) and one week later epidermally exposed to a 100 % concentration of test substance (48 h patch treatment). Ten control animals were similary treated, but with vehicle alone. Two weeks after the epidermal application all animals were challenged with 100 % test substance and the vehicle (24 hour patch). Under the conditions of the test no sensitizing effects were observed in any of the 20 animals at all. Based on these results, test item should not be classified as a contact sensitizer.