Registration Dossier

Administrative data

Description of key information

Weight of evidence from RA-S CAS 112-84-5 and RA-S Amides, C16-C18 (even numbered), Skin irritation: not irritating
RA-S CAS 112-84-5, Eye irritation in vivo (EU Method B.5): not irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

There is no data available on the skin and eye irritation potential of docosanamide (CAS 3061-75-4). In order to fulfil the standard information requirements set out in Annex VIII, 8.1 and 8.2, and in accordance with Annex XI, 1.5 of Regulation (EC) No 1907/2006, read-across from structurally very closely related substances is conducted.

A detailed justification for the analogue approach is provided in the technical dossier (see IUCLID sections 7.1 and 13).

Skin irritation

Reliable and GLP conform studies investigating the skin irritation potential are available for the structurally related substances (Z)-Docos-13-enamide (CAS 112-84-5) and Amides, C16-C18 (even numbered), which are used for read-across based on the analogue approach.

The skin irritating potential of Amides, C16-C18 (even numbered) was investigated in an in vitro skin irritation test using a human skin model according to EU Method B.46 (Warren, 2010). This is a validated method that has been accepted by the authorities in the light of animal welfare for the assessment of skin irritating potential. Three replicates of intact reconstructed human epidermis (EPISKIN Model) were topically treated with the test substance for 15 minutes, followed by a 42-hour post-exposure incubation period. After exposure to the test substance, cell viability was determined compared to the control by means of the colourimetric MTT reduction assay. No adverse effects on cell viability in the human epidermal culture compared to the negative control were observed after 15 min exposure to the test substance. The positive (5% SDS) and negative (PBS) controls included showed the expected results, and thus confirmed the validity of the assay. Therefore, the structurally related substance was considered to be non-irritating to the skin in vitro under the conditions of the test.

In addition to the in vitro data, there also exists a study on the skin irritation potential of the structurally related substance (Z)-Docos-13-enamide (CAS 112-84-5) in rabbits according to OECD guideline 404 (Daamen, 1988). In this study, the undiluted test substance (0.5 g) was moistened with water and applied for 4 h to the shaved skin of 3 New Zealand White rabbits under semiocclusive conditions. The opposite flank of the animals remained untreated and served as control. The scoring of skin reactions (erythema and edema) was performed 1, 24, 48 and 72 h after removal of the dressing. The test substance caused only very slight erythema in all three animals 1 h after removal of the dressings, which were fully reversible thereafter. No further skin reactions and no signs of systemic toxicity were noted at any other reading time point in any of the treated animals. The mean erythema and edema scores after 24, 48 and 72 h were 0 for all 3 animals. Therefore, the results demonstrate that the structurally related substance (Z)-Docos-13-enamide (CAS 112 -84 -5) was not irritating to skin.

Based on the weight of evidence from all available data on skin irritation of the structural analogues, it may be concluded that docosanamide (CAS 3061-75-4) is not irritating to skin, either.

 

Eye irritation

An eye irritation study performed in compliance with Eu method B.5 and GLP is available for the structurally very closely related substance (Z)-Docos-13-enamide (CAS 112-84-5), which is used for read-across based on the analogue approach (Bradshaw, 2010). The undiluted test material (ca. 0.1 mL) was placed into the conjunctival sac of one eye of 3 New Zealand White rabbits each. The other eye remained untreated and served as control. The eyes were examined and scored 1, 24, 48 and 72 h as well as 7 days after application. After one hour, administration of the test substance resulted in diffuse conjunctival redness and slight chemosis in two of the animals, whereas the other animal showed slight conjunctival redness and chemosis, respectively. Conjunctival redness had resolved in one animal by day 3 and in the other two animals between days 3 and 7 of the study. In all animals, chemosis was fully reversible within 3 days after test substance instillation. No iridial and corneal effects and no signs of systemic toxicity were observed in the animals at any observation time point. The mean conjunctivae and chemosis scores over all relevant observation time points ( 24, 48, and 72 h) were 1/1/0.67 and 0.67/0.33/0, respectively, for the 3 individual animals. For iris and cornea, mean scores of 0 after 24, 48 and 72 h were obtained for all 3 animals. Considering the mild character and the complete reversibility of the observed effects within 7 days, the structurally related substance erucamide was considered to be not irritating to the eyes.

Therefore, it is anticipated that docosanamide (CAS 3061-75-4) does not exert an eye irritation potential, either.


Justification for selection of skin irritation / corrosion endpoint:
No data is available on the skin irritation potential of docosanamide (CAS 3061-75-4). Therefore, hazard assessment is conducted by means of read-across from structurally very closely related substances and weight of evidence from the available studies, based on an analogue approach.

Justification for selection of eye irritation endpoint:
No data is available on the eye irritation potential of docosanamide (CAS 3061-75-4). Therefore, hazard assessment is conducted by means of read-across from a structurally very closely related substance, based on an analogue approach.

Justification for classification or non-classification

The available data on the skin and eye irritation of substances structurally related to docosanamide (CAS 3061-75-4) according to the criteria of Regulation (EC) No 1907/2006, Annex XI, 1.5, do not meet the criteria for classification according to Regulation (EC) No 1272/2008 or Directive 67/548/EEC; therefore, docosanamide (CAS 3061-75-4) is not expected to exert a skin and eye irritation potential, either, and the data are conclusive but not sufficient for classification.