Registration Dossier

Administrative data

Endpoint:
basic toxicokinetics
Type of information:
other: Estimated from know biochemical processes
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Based on limited information on the parent compound but executed with scientific rigor and other known metabolic pathways.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report Date:
2011

Materials and methods

Principles of method if other than guideline:
Estimated from known biochemical processes.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Dimethly glutarate (DMG), using Dibasic Esters (DBE) as analog.

Results and discussion

Main ADME resultsopen allclose all
Type:
absorption
Results:
Estimated to be rapid
Type:
distribution
Results:
Estimated to be blood flow limited to aqueous compartments
Type:
metabolism
Results:
Estimated metabolites include: methanol, monomethyl glutarate, and glutaric acid.
Type:
excretion
Results:
Estimated to be excreted primarily in urine.

Toxicokinetic / pharmacokinetic studies

Details on absorption:
DMG, and the other DBE single esters, has a relatively low volatility for a solvent, as evidenced by its low vapor pressure and its elevated boiling point. DMG¿s moderate log Kow (0.49) and low molecular weight (160) are favorable for absorption in general, however, substances with such a log Kow value may be poorly soluble in lipids and therefore not readily absorbed into the fat compartment. DMG is easily water soluble (63.1 g/L), which favors absorption into the aqueous compartment. Experimental evidence shows that DMG is absorbed by the olfactory epithelial cells of rats and rapidly metabolized within these cells. It is not known whether DMG is taken up actively by the olfactory epithelial cells or whether DMG passively diffuses into these cells, because of its log Kow. In addition, an estimated (EPA Dermwin v2.01) dermal permeability coefficient, Kp, of 4.9 x 10-4 cm/hr suggests that DMG can be absorbed through the skin.
Details on distribution in tissues:
It is likely that DMG is rapidly metabolized to methanol and DMG-monomethyl ester (Monomethyl glutarate), and then to DMG-diacid (Glutaric acid) by ubiquitous, non-specific, carboxylesterases present in various organs (see Metabolism section, below). Therefore, the distribution of DMG, and its metabolites, would be expected to be blood flow limited. The rapid metabolism has been well described for DBE and the single esters, including DMG, in the nasal olfactory epithelium of rats. The metabolites identified are progressively rendered more polar and are thus rendered more easily distributed into the aqueous compartment for excretion/elimination via the urine.
Details on excretion:
No data are available with regard to the excretion properties of DMG, however the small mw (160) of DMG, it water solubility, and its metabolism to more polar molecules, by carboxylesterases, suggest that DMGs¿ breakdown products would be primarily eliminated from the body via the urinary route.

Metabolite characterisation studies

Metabolites identified:
yes
Details on metabolites:
Proposed in the illustration attached below is the metabolism profile of DMG and the other two single esters of DBE (DMA and DMS). These metabolites, as chemical classes, have been identified in peer reviewed literature (Bogdanffy and Frame, 1995) and form the basis for the understanding of how the dibasic esters are metabolized. Metabolism of the resultant monomethyl esters and diacids is well understood and recorded in the scientific literature.

Reference:
Bogdanffy, M.S. and Frame, S.R. (1995). Olfactory Mucosal Toxicity. Integration of Morphological and Biochemical Data in Mechanistic Studies: Dibasic Esters as an Example. Published in Nasal Toxicity and Dosimetry of Inhaled Xenobiotics: Implications for Human Health. edited by Miller F.J. pp. 205- 219. ISBN: 1-56032-366-3.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other: Not expected to bioaccumulate based on expert judgement from known biochemical processes.
Executive summary:

Dimethyl glutarate is expected to be rapidly absorbed into the blood stream following oral exposure, has the potential to be absorbed through the skin, and is expected to be rapidly metabolized, including by olfactory epithelial cells, to methanol, monomethyl glutarate, and glutaric acid. Excretion of DMG's metabolites is expected to be primarily in urine.