Hexadecyl acetate

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:

19 October 1956 to 27 December 1956

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards, well documented and acceptable for assessment.

Reason / purpose for cross-reference:

reference to other study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Intracutaneous injection of test material in physiological saline on alternate days to a total of ten injections in each of eight male guinea pigs.

GLP compliance:

no

Remarks:

investigation took place prior to introduction of GLP

Type of study:

intracutaneous test

Species:

guinea pig

Strain:

other: White

Sex:

male

Details on test animals and environmental conditions:

- Eight, normal, healthy, white male guinea pigs, each weighing 300 to 400 g, were used for the experiment.
- Animals were maintained on a regular diet of rabbit pellets supplemented with spinich and kale throughout the experiment.
- As much hair as possible was removed from the sides and back of each guinea pig with electric clippers.

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

0.1 % suspension of test material

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

0.1 % suspension of test material

No. of animals per dose:

Eight

Details on study design:

- The test material was made up as a 0.1 % suspension in physiological saline and injected using a 0.25 mL syringe with a 0.5 inch 26 gauge needle.
- Injections were made every other day until a total of ten had taken place.
- The first injection was 0.05 mL while the remaining injections were all 0.1 mL.
- An area consisting of 3-4 cm2 was used for the site of the injection. However, the inital injection was given slightly below the sensitisation area.
- Two weeks after the final injection, a test injection of 0.05 mL of a freshly prepared suspension was administered.
- Reaction readings were made 24 hours after the initial and final 0.05 mL injections.

Positive control substance(s):

no

Positive control results:

Not applicable

Reading:

1st reading

Clinical observations:

Small raised areas

Remarks on result:

other: Reading: 1st reading. Clinical observations: Small raised areas.

Reading:

rechallenge

Clinical observations:

No effects greater than initial injection

Remarks on result:

other: Reading: rechallenge. Clinical observations: No effects greater than initial injection.

- Twenty four hours after the initial injection, small raised areas were observed.

- These areas showed a slight increase in colour when compared to the surrounding area.

- The swellings were approximately 4-5 mm in diameter and 3-4 mm in height.

- Fourteen days after the last sensitising injection was given, 0.05 mL of a new 0.1 % suspension showed no greater effects than did the initial injection.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test material produced no sensitising effects in the guinea pig.

Executive summary:

METHOD

A mixture declared to contain 90 % of test item was prepared as a 0.1 % suspension in physiological saline and administered to eight male guinea pigs by intracutaneous injection (initial injection of 0.05 mL in physiological saline followed by injections of 0.1 mL to a total of ten).

RESULTS

Twenty four hours after the initial injection, small raised areas were observed. These areas showed a slight increase in colour when compared to the surrounding area and the swellings were approximately 4-5 mm in diameter and 3-4 mm in height.

Fourteen days after the last sensitising injection was given, 0.05 mL of a new 0.1 % suspension showed no greater effects than did the initial injection.

CONCLUSION

The test material produced no sensitising effects in the guinea pig.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a key study, conducted before the introduction of GLP, a mixture declared to contain 90 % of test item was prepared as a 0.1 % suspension in physiological saline and administered to eight male guinea pigs by intracutaneous injection (initial injection of 0.05 mL in physiological saline followed by injections of 0.01 mL to a total of ten).

 

Twenty four hours after the initial injection, small raised areas were observed. These areas showed a slight increase in colour when compared to the surrounding area and the swellings were approximately 4-5 mm in diameter and 3-4 mm in height. Fourteen days after the last sensitising injection was given, 0.05 mL of a new 0.1 % suspension showed no greater effects than did the initial injection. The test material was reported to cause no sensitising effects in the guinea pig.

 

In a second study, involving 56 human volunteers, the test material did not elicit any visible response in 50 out of 53 to whom 50 % test material in petrolatum (equivalent to 45 % of the test item described in this dossier) was applied to the same dermal site for 24 hours on four consecutive days for a period of three weeks. Furthermore, no evidence of skin sensitisation was found and it was predicted with 95 % certainty that at least 92.89 % of a general population would not be sensitised by the test material. It can therefore be concluded that the test item described in this dossier does not cause skin sensitisation in humans at a concentration of 45 %.

Migrated from Short description of key information:
Pre-GLP animal study concluding that a mixture declared to contain 90 % of test item did not cause sensitisation in the guinea pig supported by human data showing that the same test material did not elicit any visible response in 50 out of 53 volunteers who took part in the study.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

No evidence for skin sensitisation was reported in a pre-GLP study on the guinea pig and these data are supported by a second study involving 56 human volunteers. As a result, the test item is not classified as a skin sensitiser under the terms of Regulation (EC) No 1272/2008.