Registration Dossier

Administrative data

Endpoint:
basic toxicokinetics
Type of information:
other: Assessment of the toxicokinetic behaviour as can be derived from the available information
Adequacy of study:
other information

Data source

Materials and methods

Principles of method if other than guideline:
Review of reports summarised in the dataset

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:
Given the vapour pressure and the logP of the test substance, some of the lower alkylated material may be absorbed via the lung if inhaled. For oral absorption it can be anticipated that with increasing alkylation the logP is increasing, resulting in lower oral bioavailability. It is possible that absorption of the oligomers may occur following oral administration, but it is more likely that any absorption is of hydrolysis products derived from the oligomers. It can be postulated that absorption decreases with increasing degree of alkoxylation due to an increase in molecular weight.
Given the logP value, dermal absorption is likely to be limited.
Details on distribution in tissues:
Given the logP value and water solubility, it is likely that any absorbed substance will be widely distributed in body water and it is unlikely that they will accumulate in tissues.
Details on excretion:
In the unlikely event that unmetabolised higher molecular weight material is absorbed, it is likely to be excreted in bile. In rat the molecular weight threshold for biliary excretion is around 350, in human it is about 500. The material most likely to be absorbed is likely to be hydrolysed and the products appear in urine, except when the end point of metabolism is carbon dioxide. Carbon dioxide will be exhaled.

Metabolite characterisation studies

Metabolites identified:
yes
Details on metabolites:
1,4 -Butynediol is expected to metabolize to 4-hydroxy-2-butynaldehyde (4-OH-butynal) and potentially further to 4-hydroxy-2-butyne-monocarboxylic acid and further yet to 2-butyne-1,4-dicarboxylic acid. 

Any other information on results incl. tables

There are no experimental studies on the toxicokinetics of 2-butyne-1,4-diol, ethoxylated (>1 < 4.5 mol EO).

Bioavailability may be extrapolated by the incremental fragment method of Suzuki and Kudo (1990). By this alkoxylation is modulating (decreasing) toxicity from the core substance by substitution of a hydroxyl group: This is based on varying physicochemical properties of the alkoxylated molecules, e.g. an increase in logP value and its molecular weight. The combined effect of these changes is to reduce the bioavailability.

Applicant's summary and conclusion

Executive summary:

There are no experimental studies on the toxicokinetics of ethoxylated and propoxylated sucrose. Sucrose (the core substance) and propane-1,2-diol and oligomers (the ethoxylated and/or propoxylated side chains) are possible models for the absorption of the ethoxylated and propoxylated sucrose. Sucrose has eight free hydroxy groups, thus oligomers are likely to consist of chains of between one and three monomers.

 

Sucrose is unlikely to be absorbed by passive diffusion, but, if absorbed by passive diffusion, absorption would be in the stomach and upper intestine where the alcohol groups are unionised. Sucrose is hydrolysed in the brush border of the intestine and the two monosaccharides, fructose and glucose, and these carbohydrates are absorbed by active transport. Propane-1,2-diol and [(methylethylene)bis(oxy)]dipropanoloxydipropanol are absorbed when administered orally, probably by passive diffusion. Essentially, the ethoxylated and propoxylated sucrose is non-toxic.(partly cited fromIlling, H P A, Barratt, M D (2007 revised 2009). Grouping of NLP ‘Polyols’ and their Toxicokinetics Assessments. Confidential report to the European Diisocyanate and Polyols Producers Association. December 2007, revised 2009.)