Registration Dossier

Administrative data

Key value for chemical safety assessment

Effects on fertility

Additional information

From repeated dose studies and developmental toxicity studies with components of the UVCB substance or their close homologues, there is no evidence for a toxicity to reproduction.

With regard to the Guerbet alcohol components of the UVCB, t was concluded by the REACH consortium in charge of these compounds that the endpoint fertility could not be fully evaluated on the basis of the available information. Consequently, a two-generation study (OECD 416) for 2-hexyldecan-1-ol (C16, CAS 2425-77-6) was proposed by the consortium. Once the study is finished, it can be used to support the evaluation of the UVCB substance, as 2-hexyldecan-1-ol is a major component, and also a major metabolic degradation product of the ester components.

Effects on developmental toxicity

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
1 000 mg/kg bw/day
Additional information

The UVCB substance to be registered is a mixture of the two Guerbet alcohols 2 -hexyldecan-1-ol & 2-octyldodecan-1 -ol and their corresponding esters with C12 and C14 fatty acids. Developmental toxicity studies are not available for the UVCB substance. The potential to induce adverse effect on development is evaluated on the basis of experimental data for Guerbet alcohols and esters of branched alcohols with fatty acids.

Of these two substance classes present in the UVCB substance, the Guerbet alcohols are considered to have the higher impact on the toxicological evaluation, for the following reasons:

-      The two Guerbet alcohols are the major components in the UVCB substance, accounting for appr. 30-50%

-      The ester components are expected to be metabolized to fatty acids and the two free Guerbet alcohols, thus contributing to the fraction of Guerbet alcohols

-      In comparison to the Guerbet alcohol esters, the free Guerbet alcohols have a lower molecular weight, which would favor their uptake

-      Having a free functional group, the Guerbet alcohols are more prone to undergo physiological reactions

A well-documented OECD 414 developmental toxicity study in rats is available for 2-octyldodecan-1-ol (C20 Guerbet alcohol). The substance is not cumulatively toxic to pregnant rats and does not reveal embryotoxic, fetotoxic or developmental effects up to the highest dose tested (1000 mg/kg bw/d). Due to their structural similarity no developmental toxicity is expected for the other Guerbet alcohols of this category either.

Concerning the esters of 2 -hexyldecan-1-ol & 2-octyldodecan-1 -ol with C12 and C14 fatty acids, no study was available for the specific components as such. Taking into account toxicokinetic aspects, it can be expected that the esters are cleaved in the body to the corresponding Guerbet alcohols and fatty acids. For the Guerbet alcohols, an OECD 414 study with2-octyldodecan-1-ol hasalready been discussed in this chapter. The other type of cleavage products, C12 and C14 fatty acids, is identical with nutrient fatty acids contained in the daily diet. Therefore, a toxic impact is not assumed. 

A part of the esters contained in the UVCB substance might not undergo a metabolic cleavage and could theoretically be absorbed after micellular solubilisation. Therefore, developmental toxicity data for esters of branched alcohols with fatty acids were also taken into account. A segment Ii study is available for a close homologue of the ester components present in the UVCB, the substance fatty acids, C16-18, 2-ethylhexyl esters (CAS 91031-48-0). The close homologue differs in the range of the fatty acid chains (2-6 carbon units longer compared to the esters in the UVCB). Furthermore, the alcoholic side chain is also shorter (close homologue: C8 branched alcohol, esters in the UVCB substance: C16 or C20 branched alcohol). As the differences concern on the length of the molecule, but not additional functional groups, the close homologue fatty acids, C16-18, 2-ethylhexyl esters seems to be well suited for a read-across to the esters in the UVCB.

The close homologue did not cause any embryo- and foetotoxic or teratogenic effects up to a dose of 1000 mg/kg bw/d. The dams tolerated the applied dose levels of up to 1000mg/kg bw/day without lethality and clinical signs of systemic toxicity.

On the basis of available data, the UVCB to be registered is not expected to have an adverse effect on embryonic development.

Toxicity to reproduction: other studies

Additional information

Available data are conclusive, but not sufficient. For the Guerbet alcohols, which are major components of the UVCB substance and also major metabolic degradation products of the esters present in the UVCB, a 2 -generation study was proposed by the REACH consortium in charge for the Guerbet alcohols. Once conducted, his study could be used to further assess potential effects on fertility of the UVCB as well.

Justification for classification or non-classification

Additional information