Ethyl palmitate

Endpoint summary

Description of key information

Based on the category approach and according to the available studies for skin sensitisation assessment, the target substance, ethyl palmitate, was considered to be not sensitising to guinea pigs skin. Hence, the ethyl palmitate was not classified for skin sensistisation.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

See attached report for justification and rationale of the category approach (Section O Categories and Section 13 Assessment Report)

Remarks on result:

no indication of skin sensitisation

Table 1: Results from key studies performed on the source substances of the category

Common name	CAS	Skin sensitisation
Isopropyl myristate	110-27-0	Experimental result: Not sensitising
Isopropyl palmitate	142-91-6	no data
Ethyl oleate	111-62-6	no data
Fatty acids, C16-18, butyl esters	85408-76-0	no data
Fatty acids, C16-18 and C18-unsatured, isobutyl esters	84988-79-4	no data
Isopropyl isostearate	68171-33-5	no data
Ethyl linoleate	544 -35 -4	No data

 

All category members are subject to enzymatic hydrolysis by pancreatic lipases resulting in free acids and alcohol. Based on current literature, when absorbed from intestines and carried through blood stream, fatty acids are oxidized by beta-oxydation pathway in order to provide energy for cell and stored as glycerides esters in fat deposit. The alcohols are primarily metabolized in the liver.

Hence, it can be stated that the members of the category have the same toxicity due to the same metabolic pathways when absorbed in the organisms.

One study was performed on the isopropyl myristate. It was conducted according to OECD 429 guideline method, using guinea pigs. This study did not showed positive results or sensitisation after animal treatment. .

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the category approach and according to the results of the available studies of the source substances, the target substance was considered to be not sensitising when applied dermally. Hence, the ethyl palmitate was not classified for skin sensitisation.

Executive summary:

According to the Regulation (EC) NO. 1907/2006, Annex XI, 1.5, A Read-Across Category was performed in order to provide informations on the Ethyl Palmitate.

This category was based on common and shared physico-chemical and structural properties as:

- common functional group,

- common precursors and the likehood of common impurities as well as common breakdown products via biological processes, which are chemically structurally similar, and

- constant pattern in the changing of the potency of the properties across the category.

The fatty acids linked with esters have a common metabolic fate in organisms as glycolytic and fatty acid pathways after first hydrolysis step which led in breakdown products. The common toxicokinetic properties and behavior are expected due to the constant pattern (esters and the fatty acid chain). The toxicological profiles between the members of the category are expected to be the same in organism.

Based on the available information for skin sensitization assessment, No adverse effect or sensitising effect were observed when administered to guinea pigs. According to physic-chemical similarities betsween source substances and target substance, it can be stated that the ethyl palmitate showed same toxicological profile. Hence, no classification was made for the ethyl palmitate.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The category group covers alcohol linked with fatty acid chains unsatured and satured. This category includes monoconstituent chemicals and UVCB substances varying acid chain length (C14 to C18) and based on alcohol function type (including ethanol, butanol and isopropanol). This approach was performed in order to provide sufficient information for physicochemical, ecotoxicological and toxicological characterizations of the ethyl palmitate. Based on structural and physic-chemicals similarities, available experimental studies from source chemicals could be used for the target substance ethyl palmitate.

This category group includes:

-       Isopropyl myristate                                                 CAS 110-27-0

-       Isopropyl palmitate                                                 CAS 142-91-6

-       Ethyl linoleate                                                         CAS 544-35-4

-       Ethyl oleate                                                            CAS 111 -62-6

-       Fatty acids, C16 -18, butyl esters                          CAS 85408-76-0

-       Fatty acids, C16 -18 and C18-unsatured isobutyl esters              CAS 84988-79-4

-       Isopropyl isostearate                                                                     CAS 68171-33-5

-       Target substance : Ethyl palmitate                                                  CAS 628-97-7

In accordance with article 13 (1) of Regulation (EC) No. 1907.2006, “information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met. In particular for human toxicity, environmental fate and ecotoxicity, information shall be generated whenever possible by means other than vertebrate animal tests which includes the use of information from structurally related substances (grouping or read across)”. Therefore, the available experimental data were collected and evaluated according to Annex XI requirements.

Summary of the available studies for skin sensitization assessment.

Isopropyl myristate CAS 110 -27 -0

A key study was available for skin sensitization assessment on the Isopropyl myristate. This study was performed with a Magnusson & Kligman method (guinea pigs maximisation test) similar to OECD Guideline 406. Pirbright Hartley guinea pigs were used. Intradermal and epicutaneaous induction phase was performed with Carboxymethylcellulose as vehicle with 5% concentration of test item for dermal application. The challenge phase was performed under occlusive condition and dermelly, the test item was used at 25% concentration. No sensitization was observed after challenge. Hence the test item Isopropyl myristate was not classified according to CLP criteria for skin sensitization.

Ethyl palmitate CAS 628 -97 -7

Two reports are available for assessment on the ethyl palmitate and palmitic acid. Predictions using OECD ToolBox V4.1 software were conducted and were considered as valid.Based on these information, the ethyl palmitate is not considered as skin sensitizer. Additionally, the palmitic acid was assessed. According to current litterature, the ethyl palmitate could be hydrolized by skin lipase into palmitic acid and ethanol. The palmitic acid could vehicled potential sensitizing effect. Prediction using OECD toolbow v4.1 showed no positive sensitising effect using read across with analog substances. Hence, the palmitic acid was not considered as skin sensitizer.

Justification for classification or non-classification

Based on the category approach and according to the available studies for skin sensitisiation assessment, the target substance, ethyl palmitate, was considered to be not sensitising to guinea pigs skin. Hence, the ethyl palmitate was not classified for skin sensistisation.