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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:
21st February - 6th April 1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Conducted prior to the GLP guidelines

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report date:
1979

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: method described by the Magnusson and Kligman "allergic contact dermatitis in the guinea pigs"
Version / remarks:
"allergic contact dermatitis in the guinea pigs" Ed Ch. C. Thomas Springfield, Illinois, USA (1970)
GLP compliance:
no
Remarks:
Conducted prior to the GLP guidelines
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The in vivo guinea pig maximisation test was already available (performed in 1979) and reliable to evaluate the skin sensitization potential and the classification determination.

Test material

Constituent 1
Chemical structure
Reference substance name:
2,6-dimethyloct-7-en-2-yl acetate
EC Number:
258-751-7
EC Name:
2,6-dimethyloct-7-en-2-yl acetate
Cas Number:
53767-93-4
Molecular formula:
C12H22O2
IUPAC Name:
2,6-dimethyloct-7-en-2-yl acetate
Test material form:
liquid
Specific details on test material used for the study:
100 ml of the test material, dihydromyrcenyl acetate (DHMA) was received on Januray 31, 1979. It was a clear colourless fragrance material.

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: SPF guinea pigs
Sex:
male
Details on test animals and environmental conditions:
A total of 15 young male albino SPF guinea pigs, weighing from 315 to 538 g were obtained from the Central Institute for the breeding of Laboratory animal TNO, Zeist, The Netherlands. The experiment was preceded by an acclimatization period of 10 days to accustom the animals to the environmental conditions prevailing in our laboratory. The guinea pigs were randomly divided into 2 groups, viz. one control group and one test group comprising 5 and 10 animals respectively. They were kept under conventional conditions and individually housed in suspended stainless steel cages, fitted with wire mesh floors and fronts.
Animla room temperature relatively humidity and lighting were controlled at 23+/-1°C , 50+/-% and 12 hours a day respectively. All guinea pigs were fed stock diet enriched with vitamin C, which was provided ad libitum together with tap water.

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
other: Freund's adjuvant and distilled water
Concentration / amount:
2 injections of 0.05 ml Freund's Complete adjuvant
2 injections of 0.05 ml of a 10 per cent DHMA dilution in propylene (PG)
2 injections of 0.05 ml of a 10 per cent DHMA suspension in freund's Adjuvant and PG (1:1)
2 injections of 0.05 ml of a 10 per cent DHMA suspension in Freund's Complete adjuvant and PG (1:1)
A concentration of 10% DHMA was chosen for induction because this concentration induced only moderate irritation reactions in preliminary observations.
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
undiluted DHMA
Day(s)/duration:
48 hours
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: vaseline
Concentration / amount:
10% of DHMA in vaseline
No. of animals per dose:
10 animals
Details on study design:
Induction via intradermal route: an area of 4 x 6 cm of the shoulder region was shaved with electric clippers. Then at short intervals, the intradermal injections were given in an area of 2 x 4 cm. A total of 6 injections was adminstered in 2 rows of 3.

Induction via topical application: One week after the injections, the same area was shaved again and topically treated with the test susbtance. A patch of 2 x 4 cm Whatman 3 mm filter paper was soaked in undiluted DHMA and then placed on the shaven smin and covered by paraplast which was kept in place by adhesive tape. This in turn was firmly secured by the self sticking bandage and left in place for 48 hours.

Challenge: the animals were challenged at day 14 after the topical induction on the right flank of which an area of 5 x 5 cm was shaven. For this treatment DHMA was mixed in vaseline. A concentration of 10% (w/w) which proved to be non irritating in a preliminary test, was used for the challenge. A small amount of the 10% mixture was applied to the shaved area of each animal and gently massaged in with a glass rod for about 30 seconds. The material applied covred an area of about 2 x 2 cm and was covered by a patch of 2 x 2 cm Whatman 3 mm filter paper and paraplast, kept in place by adhesive tape. At the same time the challenge treament was also applied to 5 controls that had not been treated before. Since nearly all animals lost their bandage the challenge was repeated one week later.
Challenge controls:
5 controls
Positive control substance(s):
not specified

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
only very slight erythema in all guinea pigs after the topcial application in the induction phase of the study
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
other: Positive control was not included
Hours after challenge:
24
Group:
positive control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
0
Clinical observations:
Not applicable
Remarks on result:
other: Positive control was not included

Any other information on results incl. tables

All animals remained in a good health during the experiment and gained weight. The intradermal injections given in the induction phase of the study resulted in the following reactions:

1) Freund's Complete Adjuvant : abscesses

2) 10% DHMA in PG: abscesses

3) 10% DHMA in adjuvant and PG (1:1): abscesses

The undiluted DHMA induced a very slight erythema in all guinea pigs after the topical application in the induction phase of the study. Upon the 1st and 2nd challenge none of the animals reacted positively .

The challenge dose generally provoked no erythema or oedema in any of the tested animals. At the same time, none of the controls reacted positively.

Applicant's summary and conclusion

Interpretation of results:
other: Not a skin sensitiser
Remarks:
according to EU CLP (EC No. 1272/2008 and its amendments).
Conclusions:
The substance is not a skin sensitiser in the GPMT test according to OECD TG 406.
Executive summary:

The substance was examined fo possible sensitization potential in guinea pigs by means of the maximisation test according to the method described by the Magnusson and Kligman "allergic contact dermatitis in the guinea pigs". A total of 15 young male albino SPF guinea pigs were used for this test including 5 animals for the control.

The induction was firstly done via intra dermal injection: 2 injections of 0.05 ml Freund's Complete adjuvant 2 injections of 0.05 ml of a 10 per cent test substance dilution in propylene (PG) and 2 injections of 0.05 ml of a 10 per cent test substance suspension in freund's Adjuvant and PG (1:1) and 2 injections of 0.05 ml of a 10 per cent test substance suspension in Freund's Complete adjuvant and PG (1:1).

A concentration of 10% test substance was chosen for induction because this concentration induced only moderate irritation reactions in preliminary observations. Secondly the induction was done via topical route using undiluted test material. All animals were challenged with 10% test substance at day 14 after the topical induction.

All animals remained in a good health during the experiment and gained weight. The intradermal injections given in the induction phase of the study resulted in the following reactions:

1) Freund's Complete Adjuvant : abscesses

2) 10% test substance in PG: abscesses

3) 10% test substance in adjuvant and PG (1:1): abscesses

The undiluted test substance induced a very slight erythema in all guinea pigs after the topical application in the induction phase of the study. Upon the 1st and 2nd challenge none of the animals reacted positively .

The challenge dose generally provoked no erythema or oedema in any of the tested animals. At the same time, none of the controls reacted positively. From these test results it is concluded that under the test conditions of this experiment the substance induced no sensitization.

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