Carboxylic acids, C5-9, triesters with 2-ethyl-2-(hydroxymethyl)propane-1,3-diol

Endpoint summary

Description of key information

There is no toxicokinetics information available on the target substance. There are 3 studies available on similar structures, which indicate that the bioaccumulation potential is likely to be low.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

Read-across justification

 From medium-long fatty chain triglycerides

·Carbon number in Fatty Acids: C6 -18     

·Carbon number in Polyol: C3

·Total Carbons in Polyol Ester: C21 - C57     

·Molecular Weight:     386 - 890

 

To Fatty Acids, C5 -9

·Carbon number in Fatty Acids: C5-9     

·Carbon number in Polyol: C6

·Total Carbons in Polyol Ester: C26 - C32   

·Molecular Weight: 400 - 540  

All of them are triesters formed by the esterification of a triol (glycerin in the source substances and trimethylolpropane in the target one).

 For all of them, it is valid to assume that, when metabolism of these triesters takes place, this firstly leads to the generation of the corresponding fatty acids and of the polyol alcohol.

For the source substances this relates to glycerin and three C6 -18 fatty chain acid units.

For the target substance “TMP Fatty Acids, C5 -9” this relates to trimethylolpropane and three C5-9 fatty chain acid units.

It is not expected significative different behaviour in terms of enzymatic lipolysis by gastric and duodenal juice among the source substances and the target one in consideration of the similar lenght chain and structure distribution of the involved fatty acids and of the similar structure of the two involved polyols, both non toxic molecules and not classified according to the 1272/2008 EC.

The target substance (similarly to the source substances) has an estimated water solubility of < 5.289 x 10-5mg/L at 25 ° C and a predicted log Kow value > 8.7. The oral absorption of highly lipophilic substances (log Kow ≥ 4) may be limited by the inability of such substances to dissolve in gastrointestinal fluids and therefore make contact with the mucosal surface. However, the absorption of such substances will be increased if they undergo micellular solubilisation by bile salts. In consideration of the similar properties in these terms between the hydrolized products of the source and the target substances, no significative differences in terms of absorption rate and behaviour are expected.

With regards to the dermal absorption, at log Kow values above 6, the rate of transfer between the stratum corneum and the epidermis will be slow and will limit absorption across the skin and uptake into the stratum corneum itself may be slow. Maximum dermal absorption is often associated with values of log Kow between +1 and +2 ( ECETOC (European Centre for Ecotoxicology and Toxicology of Chemicals). Monograph No, 20; Percutaneous absorption. August 1993 ). In addition, the substance must be sufficiently soluble in water to partition from the stratum corneum into the epidermis. The target substance, similarly the source substances, has an estimated water solubility < 5.289 x 10-5 mg/L at 25 ° C therefore dermal uptake is likely to be low.

About the inhalation absorption, the target substance, as the source subtances, has a low vapour pressure, therefore a significant inhalation exposure to vapours is not expected. Moderate log Kow values (between -1 and 4) are favourable for absorption directly across the respiratory tract epithelium by passive diffusion. The target substance, as the sources substances, has a high log Kow value (> 8.7) therefore it may be taken up by micellular solubilisation particularly as the target substance, as the source substances, is poorly soluble in water (< 5.289 x 10-5mg/L at 25 ° C)

The  read-across is, then, considered justified.