2-butyl-4,4,6-trimethyl-1,3-dioxane

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 06 June 1979 and 29 June 1979.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards with acceptable restrictions.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

not specified

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

In-vivo study already available before implementation of the LLNA method

Species:

guinea pig

Strain:

other: albino SPF

Sex:

male

Details on test animals and environmental conditions:

A total of 15 young male albino SPF guinea pigs, weighing from 386 to 700g were obtained from the Central Institute for the Breeding of Laboratory animals TNO, Ziest, The Netherlands. The experiment was preceded by an acclimatization period of 10 days to accustom the animals to the environmental conditions prevailing in the 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. Animal room temperature, relative humidity and lighting were controlled at 23±1°C, 50±10% and 12 hours a day respectively. All guinea pigs were fed stock diet enriched with vitamin C, which was provided ad libitum with tap water.

Route:

intradermal and epicutaneous

Vehicle:

propylene glycol

Concentration / amount:

50%

Route:

epicutaneous, occlusive

Vehicle:

propylene glycol

Concentration / amount:

50%

No. of animals per dose:

control goup: 5
test group: 10

Details on study design:

Induction
Intradermal injections of the test substance were given both after mixing with Freund ’s adjuvant and also after mixing with propylene Glycol (PG). An area of 4 x 6 cm of the shoulder region was shaven 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 administered in 2 rows of 3. They comprised:
1) 2 injections with 0.05 ml Freund’s Complete Adjuvant;
2) 2 injections with 0.05 ml of a 50% Herboxane dilution in propylene glycol;
3) 2 injections with 0.05 ml of a 50% Herboxane dilution in Freund’s Complete Adjuvant and propylene glycol (1:1).
A concentration of 50% herboxane was chosen for induction, because this concentration induced only moderate irritation reactions in preliminary observations.
The controls were given:
1) 2 injections with 0.05 ml Freund’s complete adjuvant;
2) 2 injections with 0.05 ml of propylene glycol;
3) 2 injections with 0.05 ml Freund’s Complete adjuvant and propylene glycol (1:1).

Topical application
One week after the injections, the same area was shaved again and topically treated with the test substance.
A patch of 2 x 4 cm Whatman 3mm filter paper was soaked in undiluted Herboxane and then placed on the shaven skin of the test animals and covered by paraplast which was kept in place by adhesive tape. This in turn was firmly secured by self-sticking bandage and left in place for 48 hours.
The controls were treated in the same way, except that the patch was not soaked in Herboxane.

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, Herboxane was mixed in Vaseline. A concentration of 15% (w/w), which proved to be non-irritating in a preliminary test, was used for the challenge. A small amount of the 15% mixture was applied to a patch of 2 x 2 Whatman 3mm filter paper and then placed on the shaven area. It was covered by paraplast and kept in place by adhesive bandage and firmly secured by self-sticking tape. At the same time, the challenge treatment was applied (as described below) to 5 controls that had not been treated before.

Skin readings were made 24 hours after the challenge treatment in both control and test animals. Skin reactions were judged with the method of Draize, as described in J. Pharmacol. 82 (1944) 377-390.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

15%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: . Hours after challenge: 24.0. Group: test group. Dose level: 15%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

15%

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Group:

positive control

Remarks on result:

not measured/tested

All animals remained in good health during the experiment.

The intradermal injections given during the induction phase of the study resulted in the following reactions in the test animals:

1)     Freund’s Complete Adjuvant: abscesses

2)     50% Herboxane in PG: abscesses

3)     50% Herboxane in Adjuvant and PG (1:1): abscesses

The undiluted Herboxane induced neither erythema nor edema in guinea pigs upon the topical application in the induction phase of the study.

The challenge dose provoked no erythema or edema in any of the test animals and none of the controls reacted positively. From these results it is concluded that under the conditions of this experiment Herboxane induced no sensitization according to the classification of Magnusson and Kligman (1970).

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The undiluted Herboxane induced neither erythema nor edema in guinea pigs upon the topical application in the induction phase of the study.
The challenge dose provoked no erythema or edema in any of the test animals and none of the controls reacted positively. From these results it is concluded that under the conditions of this experiment Herboxane induced no sensitization according to the classification of Magnusson and Kligman (1970).

Executive summary:

The experiment was conducted mainly according to the method described by Magnusson and Kligman (1970).

The undiluted Herboxane induced neither erythema nor edema in guinea pigs upon the topical application in the induction phase of the study.

The challenge dose provoked no erythema or edema in any of the test animals and none of the controls reacted positively.

From these results it is concluded that under the conditions of this experiment Herboxane induced no sensitization.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

All animals remained in good health during the experiment.

The intradermal injections given during the induction phase of the study resulted in the following reactions in the test animals:

1)     Freund’s Complete Adjuvant: abscesses

2)     50% Herboxane in PG: abscesses

3)     50% Herboxane in Adjuvant and PG (1:1): abscesses

The undiluted Herboxane induced neither erythema nor edema in guinea pigs upon the topical application in the induction phase of the study.

The challenge dose provoked no erythema or edema in any of the test animals and none of the controls reacted positively. From these results it is concluded that under the conditions of this experiment Herboxane induced no sensitization according to the classification of Magnusson and Kligman (1970).

Migrated from Short description of key information:
The undiluted Herboxane induced neither erythema nor edema in guinea pigs upon the topical application in the induction phase of the study.
The challenge dose provoked no erythema or edema in any of the test animals and none of the controls reacted positively.
From these results it is concluded that under the conditions of this experiment Herboxane induced no sensitization.

Justification for selection of skin sensitisation endpoint:
The study was conducted on the target substance in vivo in an appropriate test species according to internationally recognised guidelines.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

A skin sensitiser is defined as a substance that will lead to an allergic response following skin contact.

Sensitisation includes two phases,

The induction of specialised immunological memory in an individual by exposure to an allergen.

Elicitation where the production of cell-mediated or antibody mediated allergic response by exposure of a sensitised individual to an allergen.

For skin sensitisation, an induction phase is required in which the immune system learns to react; clinical symptoms can then arise when subsequent exposure is sufficient to elicit a visible skin reaction (elicitation phase). Lower levels are usually required for elicitation than are required for induction.

Substances shall be classified as a category 1 skin sensitiser if there is evidence in humans that the substance can lead to sensitisation by skin contact in a substantial number of persons, or if there are positive results form an appropriate animal test.

When an adjuvant type guinea pig test method for skin sensitisation is used, a response of at least 30 % of the animals is considered positive.

The undiluted test substance induced neither erythema nor edema in guinea pigs upon the topical application in the induction phase of the study.

The challenge dose provoked no erythema or edema in any of the test animals.

It can therefore be concluded that the test substance is not classified as a skin sensitiser.