1,2,3,4,4a,7,8,8a-octahydro-2,4a,5,8a-tetramethyl-1-naphthyl formate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted in 1978.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

Induction: Days 0 – 20.
On Day 0, 0.1 mL of the test material undiluted and at progressively diluted solutions were applied to an area measuring 8 cm2 on the clipped flank skin of four guinea pigs per concentration group.
The applications were repeated daily for three weeks, or done five times weekly during four weeks, always using the same skin site. The application site was left uncovered.

Challenge: Days 21 – 35.
To determine whether or not contact sensitisation was induced, all the groups of guinea pigs previously treated for 21 days with the vehicle pre-treated as above, as well as six to eight untreated or only with vehicle pre-treated controls were tested on days 21 and 35 on the contralateral flank with the test material at the minimal irritating and some lower concentrations. The minimal irritating concentration was used in order to confirm biological activity determined before starting the induction (Day -1) and to exclude dales results based on instability of test materials. These tests were performed by applying with a pipette 0.025 mL of each concentration to skin areas measuring 2 cm2, the reactions being read after 24, 48 and / or 72 hours. This procedure enables the determination of the minimal sensitising concentration necessary for inducing allergic contact hyper-sensitivity and the minimal eliciting concentration necessary to cause a positive reaction.
The test material is considered allergenic at a concentration when at least one of the eight animals of the concentration group concerned shows positive reactions with non-irritant concentrations used for challenge, i.d. its threshold concentration causing skin reactions is shifted into the lower part of the concentration range used to challenge.

GLP compliance:

no

Remarks:

Study pre-dates GLP.

Type of study:

open epicutaneous test

Justification for non-LLNA method:

The study pre-dates the LLNA method.

Species:

guinea pig

Strain:

not specified

Sex:

not specified

Details on test animals and environmental conditions:

No data

Route:

epicutaneous, open

Vehicle:

other: Acetone

Concentration / amount:

3, 10, 30 and 100 %

Route:

epicutaneous, open

Vehicle:

other: Acetone

Concentration / amount:

3, 10, 30 and 100 %

No. of animals per dose:

4 animals / dose

Details on study design:

Induction: Days 0 – 20.
On Day 0.1 mL of the test material undiluted and at progressively diluted solutions were applied to an area measuring 8 cm2 on the clipped flank skin of four guinea pigs per concentration group.
The applications were repeated daily for three weeks, or done five times weekly during four weeks, always using the same skin site. The application site was left uncovered.

Challenge: Days 21 – 35.
To determine whether or not contact sensitisation was induced, all the groups of guinea pigs previously treated for 21 days with the vehicle pre-treated as above, as well as six to eight untreated or only with vehicle pre-treated controls were tested on days 21 and 35 on the contralateral flank with the test material at the minimal irritating and some lower concentrations. The minimal irritating concentration was used in order to confirm biological activity determined before starting the induction (Day -1) and to exclude dales results based on instability of test materials. These tests were performed by applying with a pipette 0.025 mL of each concentration to skin areas measuring 2 cm2, the reactions being read after 24, 48 and / or 72 hours. This procedure enables the determination of the minimal sensitising concentration necessary for inducing allergic contact hyper-sensitivity and the minimal eliciting concentration necessary to cause a positive reaction.
The test material is considered allergenic at a concentration when at least one of the eight animals of the concentration group concerned shows positive reactions with non-irritant concentrations used for challenge, i.d. its threshold concentration causing skin reactions is shifted into the lower part of the concentration range used to challenge.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

4

Remarks on result:

other: 1st reading. The challenge time was 24 Hours after the 3 week (504 hours) induction phase.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

100%

No. with + reactions:

0

Total no. in group:

6

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

NA

Capacity to cause allergic sensitisation

After daily applications over three weeks Concentration %	Sensitisation rate Number of animals positive / total
	Day 21	Day 35
100	0 / 4	0 / 4
30	0 / 4	0 / 4
10	0 / 4	0 / 4
3	0 / 4	0 / 4

Interpretation of results:

GHS criteria not met

Conclusions:

The preparation does not sensitise the guinea pig in the OET.

Executive summary:

The test substance was assessed for skin sensitisation potential using an open epicutaneous test on guinea pigs. The test substance was not sensitising under the conditions of the test.

Reference 2

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1971

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

FDA approved Draize Test method.

Qualifier:

according to guideline

Guideline:

other: Draize Technique

Version / remarks:

Method approved by FDA

Deviations:

not applicable

Principles of method if other than guideline:

Fifty-three subjects, 39 female and 14 male, of representative age groups concluded a full sensitization and challenge test study in accordance with the Draize repeated insult technique.

GLP compliance:

not specified

Type of study:

patch test

Justification for non-LLNA method:

The study pre-dates the LLNA method.
Thie is also a validated method by the FDA based on the Draize Technique.

Species:

human

Strain:

other: Not applicable

Sex:

male/female

Details on test animals and environmental conditions:

Not applicable to human study

Route:

epicutaneous, occlusive

Vehicle:

no data

Concentration / amount:

0.5 cc

Route:

epicutaneous, occlusive

Vehicle:

no data

Concentration / amount:

0.5 cc

No. of animals per dose:

Fifty-three subjects; 39 female and 14 male.

Details on study design:

In order to assure the completion of both the sensitizing and challenge test series by a minimum of fifty individuals, fifty-eight volunteers were inducted into the study at its beginning. The larger number of volunteers inducted into the study is to assure the completion of the entire investigation by at least the desired fifty people, taking into consideration the anticipated los s or elimination of some of these subjects because of various personal reasons or occasionally, because of resultant irritations (from adhesive tape or other sources) which may result from the repeated applications and removals of the patch tests. The fifty-eight subjects were selected on a random basis in the order of their applying for participation in the study, except that no person was accepted with active dermatologic conditions or other discernible illnesses. Previous sensitivities or history of allergy were not considered to be reasons for rejection, but were noted for any value such information could have in interpreting the results of the study.

The technique employed in this study was that of the repeated insult method approved by the Food and Drug Administration and known as the Draize Technique. This procedure consists of the repeated applications cyclicly of closed patch tests with 0.5 cc. of each solution being applied to individual absorbent patches, one preparation to each specific patch. These patches are applied to the area to be tested in a definite fixed sequence, identical at each testing. They are then secured by means of overlying strips of impervious adhesive tape which are then further occluded with additional overlying strips of similar tape.

The patches are allowed to remain in situ for 48 hours and are then removed, at which time readings are recorded. Following the removal of these tests, identical, similarly prepared patches are then applied to the next area in the identical sequence with the identical occlusive precautions. The customary exceptions to this 48 hour contact are:
(1) over the weekends when applications remain in situ for 72 hours until the following Monday and,
(2) only the first application is removed 24 hours after application to check for any primary irritation in this larger group prior to proceeding with the full length test exposures. These prolonged contacts over the weekend offer a greater opportunity for irritation and sensitization and would, if such potentialities existed in these materials, add to the opportunities for their elicitation.

The initial site of application of these patch tests was the inner surface of the right deltoid area. When these patches were removed 48 hours after their application, the next application was made to the inner surface of the left deltoid area. The third application was made to the original site of the first application the inner surface of the right deltoid area, and the fourth application was made to the site of the second application, on the medial surface of the left deltoid area. Thus, the cycle of rotation of the sites of application was alternately between the inner surfaces of the right and left deltoid areas for a total of ten sensitization applications. The concluding challenge tests were applied simultaneously as precise duplicates to the inner surface of each deltoid area.
The cycle of rotation of sites was continued throughout the series of ten identical sensitization test applications of the eight preparations on the following dates:
April 13, 14, 16, 19, 21, 23, 26, 28, 30 and May 3, 5, 1971.
The eleventh visit on May 5 was for the removal of the patch tests applied on the tenth sensitization visit of May 3. This completed the sensitization series during which the objective is to induce the development of sensitization to the preparations being tested, if such potentialities exist in these compounds. As will be noted above, the first patches were applied on April 13 and removed on April 14 with the 24 hour period of contact instead of the 48 hour period of contact as stated in the earlier portion of this report because it was desired to observe during the first application to the large number of subjects whether or not any primary irritation existed before continuing with the test for the longer or 48 hour period of contact.

There then followed a rest period after the application of the last sensitization test during which the development (so-called incubation) of sensitization was permitted to occur. On May 18, 1971, the challenge test series was applied, in the identical manner in which the sensitization applications were made, except that the tests were applied in duplicate, one set of eight patches to the inner surface of each deltoid area. These challenge test applications were removed on May 20, 1971 and a 48 hour reading was recorded. The patches were not re-applied, Instead, a loosely applied cover of plain sterile gauze was made to protect the test site area from washing, scratching or other interference with the development of any delayed reactions. On the following day May 21, a 72 hour or delayed reading was recorded to complete the study. Observations were, however, made to detect the development of any retarded responses on May 24 when the subjects returned to receive their stipends for participating in this study.

The 48 hour contact (or longer) of the materials confined by the closed patches is considered to be a stringent test permitting maximum opportunity for elicitation of any sensitization or irritation reactions. The alternation of test sites is to permit an opportunity for involution of any irritative, traumatic, non - specific or sensitizing responses which might occur from the materials being tested or from the adhesive tape used to secure the test patches. Based on present theoretical concepts, it also enhances the opportunities for the development of sensitization by doubling the series of lymph nodes exposed to the direct drainage from the test sites.

In addition to these test studies, there was performed the routine precautionary measure of checking on the primary irritative potentialities of the materials by applying them in the same manner as described above on a pilot group of ten subjects prior to the institution of these tests on: the full group. Therefore, on April 12, 1971, the eight preparations were applied in closed patches in the identical manner as described above to the inner surface of the left deltoid area on a pilot group of ten subjects. When after 24 hours of exposure there were no complaints of itching, burning or other paresthesias, and the patch test sites indicated no reactions, the full sensitization study was started on the 58 subjects. These ten subjects in the pilot group then became part of the full complement of the 58 subjects so that at the end of the sensitization series, these ten individuals had had eleven such sensitizing applications as compared to the remaining individuals who had been subjected to the ten sensitizing applications.

Prior to the application of each test series" including the challenge tests, the application site was cleansed with an ether-acetone mixture to remove any sebum or foreign material such as powders or bath oils.

Positive control substance(s):

no

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.5cc

No. with + reactions:

0

Total no. in group:

53

Clinical observations:

NA

Remarks on result:

other: Group: test group. Dose level: 0.5cc. No with. + reactions: 0.0. Total no. in groups: 53.0.

Reading:

1st reading

Hours after challenge:

0

Group:

negative control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

NA

Reading:

1st reading

Hours after challenge:

0

Group:

positive control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

NA

Of the fifty-eight subjects, including the ten individuals in the pilot group which was incorporated into the full complement of this study, fifty-three of these volunteers completed the full sensitization and challenge test investigation.

No reactions developed in response to the formulation, either in the sensitization or challenge test phases. However, there were reactions to the adhesive tape per se, involving twelve of the subjects for a total of19such tape reactions. Seven subjects developed one reaction each. Four subjects manifested 2 such reactions. One person showed 4 reactions. All reactions were of the redness and papular types with only two of the responses (in the subject with the 4 reactions) being slightly vesicular.

Ages (years)	Subjects
17 – 20	7
21 – 29	11
30 – 39	7
40 – 49	12
50 – 59	12
60 - 64	4
Total	53

Interpretation of results:

GHS criteria not met

Conclusions:

Fifty-three subjects, 39 female and 14 male, of representative age groups concluded a full sensitization and challenge test study in accordance with the described Draize repeated insult technique. There were no reactions in response to the patch tests containing any of the eight preparations, either in the sensitization or challenge test series.

The only reactions which did occur were in response to the adhesive tape materials for a total of 19 reactions in twelve of the subjects, thereby indicating the presence of a potentiality to react had the formulations been adequately stimulating to the fifty-three subjects who completed the full study.

It is therefore concluded that none of the eight preparations in the indicated concentrations, as studied in this investigation, manifested either primary irritation or sensitizing effects on the fifty-three subjects who completed this full study.

Executive summary:

Fifty-three subjects, 39 female and 14 male, of representative age groups concluded a full sensitization and challenge test study in accordance with the described Draize repeated insult technique. There were no reactions in response to the patch tests containing the preparation, either in the sensitisation or challenge test series.

The only reactions which did occur were in response to the adhesive tape materials for a total of 19 reactions in twelve of the subjects, thereby indicating the presence of a potentiality to react had the formulation been adequately stimulating to the fifty-three subjects who completed the full study.

It is therefore concluded that none of the eight preparations in the indicated concentrations, as studied in this investigation, manifested either primary irritation or sensitizing effects on the fifty-three subjects who completed the full study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The skin sensitisation potential of the test item was assessed using an open epicutaneous test on guinea pigs. Four concentrations of the test substance were administered. The animals tested at 100 % concentration showed no indication of skin sensitisation.

The test substance was also assessed using 53 human volunteers in a full sensitisation and challenge study using a repeated insult patch test. No reactions developed in response to the formulation, either in the sensitization or challenge test phases.

Migrated from Short description of key information:
The test substance was assessed for skin irritation potential using an open epicutaneous test on guinea pigs.

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

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 and solicitation were production of cell-mediated or antibody-mediate 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 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 from an appropriate animal test.

When a non-adjuvant type guinea pig test is used, a response in at least 15 % of animals is considered positive. No positive skin sensitisation reactions were elicited during the guinea pig open epicutaneous test or the human repeat insult patch test and the test substance is therefore not classified as a skin sensitiser.