Docosanoic acid, monoester with glycerol

Endpoint summary

Description of key information

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 and eye irritation potential of glycerol monobehenate is 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 and eye irritation properties of the substance.

 

The CIR (2016) expert assessment on skin irritation of glycerol monoesters describes a number of human repeat insult patch tests (RIPT) and single-insult occlusive patch tests with different glycerol monoesters tested at different concentrations. From these studies it can be concluded that in humans no indications of dermal irritation were reported in dermal irritation and skin sensitisation testing with esters of glycerol and fatty acids with a chain length of C14 and above. Further, the CIR (2016) expert assessment also describes experimental animal data on skin irritation. Form these, it can be concluded that undiluted glycerol monobehenate, glyceryl hydrogenated rosinate, glyceryl rosinate, and glyceryl stearate were not irritating to rabbit skin.

 

The CIR (2016) expert assessment on eye irritation of glycerol monoesters describes a number of experimental animal data from rabbit studies. No eye irritation were seen with undiluted glyceyl behenate and glyceryl palmitate/stearate while undiluted glyceryl rosinate showed slightly eye irritation. Same lack of clear eye irritation were seen using glyceryl oleate, glyceryl ricinoleate, glyceryl stearate when testing formulations containing 50 -100%. Further, glyceryl citrate/lactate/linoleate/oleate was not classified as ocular irritants in rabbits.

 

The overall weight of evidence indicates that glycerol monobehenate does not cause skin and irritation and should not be classified for skin and eye irritation according to (EC) No 1272/2008.

 

The available information comprises adequate, reliable studies from reference substances with similar structure and intrinsic properties. The weight-of-evidence approach 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 irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

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 irritating 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 irritation 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 irritation 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.

Remarks on result:

other: The overall weight of evidence indicates that glycerol monobehenate does not cause skin irritation and should not be classified for skin irritation 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).

The CIR (2016) expert assessment of glycerol monoesters describes a number of human repeat insult patch tests (RIPT) and single-insult occlusive patch tests with different glycerol monoesters tested at different concentrations (15-50%). These data indicate that glycerol monoesters of fatty acids with chain length of C12 and in a concentration level of 50% may induce irritation on human skin, whereas glycerol esters of fatty acids with chain length at and above C14 in a concentration level up to 50% do not cause skin irritation. From these studies it can be concluded that in humans no indications of dermal irritation were reported in dermal irritation and skin sensitisation testing with esters of glycerol and fatty acids with a chain length of C14 and above.

Further, the CIR (2016) expert assessment also describes experimental animal data on skin irritation. From these, it can be concluded that undiluted glycerol monobehenate, glyceryl hydrogenated rosinate, glyceryl rosinate, and glyceryl stearate were not irritating to rabbit skin when using occlusive patch (NZW rabbits).

The overall weight of evidence indicates that glycerol behenate does not cause skin irritation and should not be classified for skin irritation according to (EC) No 1272/2008.

Interpretation of results:

GHS criteria not met

Conclusions:

Undiluted glycerol monobehenate, glyceryl hydrogenated rosinate, glyceryl rosinate, and glyceryl stearate was not irritating to rabbit skin. In humans no indications of dermal irritation were reported in dermal irritation and skin sensitisation testing with esters of glycerol and fatty acids with a chain length of C14 and above. The overall weight of evidence indicates that glycerol behenate does not cause skin irritation and should not be classified for skin irritation according to (EC) No 1272/2008.

Executive summary:

Limited data available on skin irritation 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 irritation potential of docosanoic acid, monoester with glycerol (glycerol monobehenate) 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.

The CIR (2016) expert assessment of glycerol monoesters describes a number of human repeat insult patch tests (RIPT) and single-insult occlusive patch tests with different glycerol monoesters tested at different concentrations. From these studies it can be concluded that in humans no indications of dermal irritation were reported in dermal irritation and skin sensitisation testing with esters of glycerol and fatty acids with a chain length of C14 and above. Further, the CIR (2016) expert assessment also describes experimental animal data on skin irritation. Form these, it can be concluded that undiluted glycerol monobehenate, glyceryl hydrogenated rosinate, glyceryl rosinate, and glyceryl stearate were not irritating to rabbit skin.

The overall weight of evidence indicates that glycerol monobehenate does not cause skin irritation and should not be classified for skin irritation according to (EC) No 1272/2008.

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

Justification for classification or non-classification

Undiluted glycerol monobehenate, glyceryl hydrogenated rosinate, glyceryl rosinate, and glyceryl stearate were not irritating to rabbit skin. In humans no indications of dermal irritation were reported in dermal irritation and skin sensitisation testing with esters of glycerol and fatty acids with a chain length of C14 and above. The overall weight of evidence indicates that glycerol behenate does not cause skin irritation and should not be classified for skin irritation according to (EC) No 1272/2008.

Based on the lack of eye irritation in experimental animal testing with glycerol behenate and other esters of glycerol and other fatty acids, the overall weight of evidence indicates that glycerol behenate does not cause eye irritation and should not be classified for eye irritation according to (EC) No 1272/2008.