Docosanoic acid, monoester with glycerol

Endpoint summary

Description of key information

Some data available on skin sensitisation for docosanoic acid, monoester with glycerol (glycerol monobehenate). Glycerol monobehenate is a mono-constituent substance. The main component is docosanoic acid, monoester with glycerol, the remaining compounds are mainly fatty acids and monoesters of fatty acid and glycerol. Glycerol can also be present in a low concentration. Glyceryl monoesters (monoglycerides) are metabolized to free fatty acids and glycerol, both of which are available for the resynthesis of triglycerides.

 

The skin sesitisation potential of docosanoic acid, monoester with glycerol (glycerol monobehenate)is assessed using a weight of evidence approach based on the available data on glycerol monobehenate and the group of other monoglycerides with long chain fatty acids, having similar properties. Hereby, a larger data set is available for deriving a conclusion on the skin sensitisation properties of the substance.

Based on data from CIR (2016), it can be concluded that human repeated insult patch tests with glycerol behenate (applied neat) and other glycerol esters (glyceryl hydrogenated rosinate and glyceryl rosinate) does not indicate concern for a skin sensitisation potential.

 

No experimental animal data on skin sensitisation is available on glycerol monobehenate, however, testing with other esters of glycerol and other fatty acids (glycerol hydrogenated rosinate, glycerol rosinate,, and glycerol C16-18 and C18 mono- and dihydroxy acids) did not show indications of a skin sensitising potential.

 

Thus,the overall weight of evidence indicates that glycerol monobehenate does not cause skin sensitisation and therefore, the substance should not be classified for this endpoint according to (EC) No 1272/2008.

 

The available information comprises adequate, reliable studies from reference substances with similar structure and intrinsic properties. Weight-of-evidence is justified based on common functional group and common precursors/breakdown products. The information from these independent sources is consistent and provides sufficient weight of evidence leading to an endpoint conclusion in accordance with Annex XI, 1.2, of Regulation (EC) No 1907/2006.   

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

other: weight of evidence analysis based on expert evaluated data on hydrolysis products and structural analogues

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: based on expert group reviews

Justification for type of information:

Data are available for docosanoic acid, monoester with glycerol as well as similar glycerol monoesters (glyceryl hydrogenated rosinate, glyceryl rosinate, and glyceryl stearate) in relation to skin sensitising properties.

The following expert opinions (attached in section 13) will be used in the weight of evidence approach:

CIR 2016: Cosmetic Ingredient Review. Safety assessment of monoglyceryl monoesters as used in cosmetics. Final amended report, January 15, 2016.

Principles of method if other than guideline:

In relation to data requirements of REACH Annex VIII (1-10 t/y), data on skin sensitisation must be provided. Limited data on this endpoint is available for docosanoic acid, monoester with glycerol (glycerol monobehenate). Glycerol monobehenate is a mono-constituent substance. The main component is docosanoic acid, monoester with glycerol, the remaining compounds are mainly fatty acids and monoesters of fatty acid and glycerol. Glycerol can also be present in a low concentration. Glyceryl monoesters (monoglycerides) are metabolized to free fatty acids and glycerol, both of which are available for the resynthesis of triglycerides.

The skin sensitsing potential of this substance is therefore assessed using a weight of evidence approach based on the sparse data on glycerol monobehenate and the group of other monoglycerides with long chain fatty acids, having similar properties. Hereby, a larger data set is available for deriving a conclusion on the skin irritation properties of the substance.

A weight of evidence approach is used for the assessment of the skin irritation potential of the substance.

Type of study:

other: weight of evidence analysis based on expert evaluated data on hydrolysis products and structural analogues using in vivo/in vitro data

Justification for non-LLNA method:

In relation to data requirements of REACH Annex VIII (1-10 t/y), data on skin sensitisation must be provided. Limited data on this endpoint is available for docosanoic acid, monoester with glycerol (glycerol monobehenate). Glycerol monobehenate is a mono-constituent substance. The main component is docosanoic acid, monoester with glycerol which is present in the product at a concentration of 80-97%; the remaining compounds are mainly fatty acids and monoesters of fatty acid and glycerol. Glycerol can also be present in a low concentration. Glyceryl monoesters (monoglycerides) are metabolized to free fatty acids and glycerol, both of which are available for the resynthesis of triglycerides.

The skin sensitisation of this substance is therefore assessed using a weight of evidence approach based on existing data on glycerol monobehenate and the group of other monoglycerides with long chain fatty acids, having similar properties Hereby, a larger data set is available for deriving a conclusion on the skin sensitisation properties of the substance.

The following expert assessment with human data and experimental animal testing data (non-LLNA) is used in a weight of evidence approach:
CIR 2016: Cosmetic Ingredient Review. Safety assessment of monoglyceryl monoesters as used in cosmetics. Final amended report, January 15, 2016.

Remarks on result:

other: The overall weight of evidence indicates that glycerol monobehenate does not cause skin sensitisation and therefore, the substance should not be classified for this endpoint according to (EC) No 1272/2008.

The attached weight of evidence document describes a number of human data and experimental animal data from rabbit studies (NZW rabbits) as referenced in CIR (2016). Please see the attached document for details.

The CIR (2016) expert assessment of glycerol monoesters describes a number of human repeat insult patch tests (HRIPT) and single-insult occlusive patch tests with different glycerol monoesters tested at different concentrations, with glyceryl behenate being tested neat. In this study with glyceryl behenate, the substance was applied neat with the following characteristics. 93 subjects were included in HRIPT studies; 0.2 g applied with an occlusive patch, 9 24-h patches induction patches were applied (3x/wk for 3 wks); the challenge patch was applied to a previously untreated site after a 2-wk non-treatment period. The substance was concluded not to be a skin sensitiser.

Based on the overrall data availavle is is concluded taht human data on glycerol monobehenate indite lack of potential of skin sensitisation. Further human data on glycerol esters of other fatty acids for the great majority of data indicate lack of skin sensitisation, although isolated positive findings in one our few individuals were noted. For Portuguese gum rosin and for glycerol esters of abietic acid (diterpenoid acid) positive data skin sensitisation was found. However, these data is not considered relevant for the assessment of glycerol monobehenate, as Portuguese gum rosin as a non-purified UVCB substance contains a variety of other constituents than glycerol esters and as abietic acid has a much different structure compared to a fatty acid.

Further, the CIR (2016) expert assessment also describes experimental animal data on skin sensitisation. No experimental animal data on skin sensitisation is available on glycerol monobehenate, however, testing with other esters of glycerol and other fatty acids (glycerol hydrogenated rosinate, glycerol rosinate, and glycerol C16-18 and C18 mono- and dihydroxy acids) did not show indications of a skin sensitising potential. These data were generated from guinea pig maximisation studies. From these, it can be concluded that no experimental animal data on skin sensitisation is available on glycerol monobehenate, however, testing with other esters of glycerol and other fatty acids (glycerol hydrogenated rosinate, glycerol rosinate, and glycerol C16-18 and C18 mono- and dihydroxy acids) did not show indications of a skin sensitising potential.

Thus, the overall weight of evidence indicates that glycerol monobehenate does not cause skin sensitisation and therefore, the substance should not be classified for this endpoint according to (EC) No 1272/2008.

Interpretation of results:

GHS criteria not met

Conclusions:

Based on data from CIR (2016), it can be concluded that human repeated insult patch tests with glycerol behenate (applied neat) and other glycerol esters (glyceryl hydrogenated rosinate, and glyceryl rosinate) do not indicate concern for a skin sensitisation potential.

No experimental animal data on skin sensitisation is available on glycerol monobehenate, however, testing with other esters of glycerol and other fatty acids (glycerol hydrogenated rosinate, glycerol rosinate and glycerol C16-18 and C18 mono- and dihydroxy acids) did not show indications of a skin sensitising potential.

Thus, the overall weight of evidence indicates that glycerol monobehenate does not cause skin sensitisation and therefore, the substance should not be classified for this endpoint according to (EC) No 1272/2008.

Executive summary:

Some data available on skin sensitisation for docosanoic acid, monoester with glycerol (glycerol monobehenate). Glycerol monobehenate is a mono-constituent substance with a purity of 80-90%. The main component is docosanoic acid, monoester with glycerol, the remaining compounds are mainly fatty acids and monoesters of fatty acid and glycerol. Glycerol can also be present in a low concentration. Glyceryl monoesters (monoglycerides) are metabolized to free fatty acids and glycerol, both of which are available for the resynthesis of triglycerides.

 

The skin sesitisation potential of docosanoic acid, monoester with glycerol (glycerol monobehenate) is assessed using a weight of evidence approach based on the available data on glycerol monobehenate and the group of other monoglycerides with long chain fatty acids, having similar properties. Hereby, a larger data set is available for deriving a conclusion on the skin irritation properties of the substance.

 

Based on data from CIR (2016), it can be concluded that human repeated insult patch tests with glycerol behenate (applied neat) and other glycerol esters (glyceryl hydrogenated rosinate and glyceryl rosinate) do not indicate concern for a skin sensitisation potential.

 

No experimental animal data on skin sensitisation is available on glycerol monobehenate, however, testing with other esters of glycerol and other fatty acids (glycerol hydrogenated rosinate, glycerol rosinate and glycerol C16-18 and C18 mono- and dihydroxy acids) did not show indications of a skin sensitising potential.

 

Thus, the overall weight of evidence indicates that glycerol monobehenate does not cause skin sensitisation and therefore, the substance should not be classified for this endpoint according to (EC) No 1272/2008.

 

 

The available information comprises adequate, reliable studies from reference substances with similar structure and intrinsic properties. Weight-of-evidence is justified based on common functional group and common precursors/breakdown products. The information from these independent sources is consistent and provides sufficient weight of evidence leading to an endpoint conclusion in accordance with Annex XI, 1.2, of Regulation (EC) No 1907/2006

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on data from CIR (2016), it can be concluded that human repeated insult patch tests with glycerol behenate (applied neat) and other glycerol esters (glyceryl hydrogenated rosinate and glyceryl rosinate) does not indicate concern for a skin sensitisation potential.

No experimental animal data on skin sensitisation is available on glycerol monobehenate, however, testing with other esters of glycerol and other fatty acids (glycerol hydrogenated rosinate, glycerol rosinate and glycerol C16-18 and C18 mono- and dihydroxy acids) did not show indications of a skin sensitising potential.

Thus,the overall weight of evidence indicates that glycerol monobehenate does not cause skin sensitisation and therefore, the substance should not be classified for this endpoint according to (EC) No 1272/2008.