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Description of key information

Key value for chemical safety assessment

Additional information

There is no toxicokinetic data available. However intesive toxicokinetic studies have been conducted for the structurally related substance BMIM Cl (1-Butyll-3-Methyl Imidazolium chloride).

Absorption

The water solubility of the test substance is high caused by the presence of strongly polar sulfate and imidazolium groups. Under physiological conditions, the compound will be completely ionized in water, like BMIM Cl. Compounds need to pass the lipid membranes in the gastrointestinal wall. If there is no special transporter present, absorption Ionic substances is unlikely (1). However, as shown for BMIM, the test item may utilize intestinal cation transporters. Systemic bioavailability for BMIM Cl is 62.1% after oral administration of a 50 mg/kg dose and ca. 1, 3 or 3% (depending on the vehicle used; water, ethanol-water or DMF-water, respectively) after dermal application of 5 mg/kg in rats. Systemic bioavailability is expected to be practically the same for the test item.

 

Distribution

Due to dissociation distribution volume of the test substance is supposed to be low. Accumulation in fatty tissues is not anticipated therefore. This fits with the results for BMIM Cl. Despite systemic bioavailability of BMIM-Cl tissue disposition is negligible.

 

Metabolism and Excretion

There is no toxicokinetic data available concerning metabolism of the test substance available. The ionic structure however dose not sugest a metabolism via CYP P450. As the test substance is already water soluble, there is also no phase 2 metabolism expected. Therefore the test substance is supposed to be excreted mainly unchanged.

The test substance is expected to be excreted via kidneys. Renal excretion is supposed to be largely due to glomerular filtration. The glomerular filtration rate is 120 ml/min.  (2). Ethyl sulfate is a minor metabolite of ethanol (alcohol), formed by sulfate conjugation. Elimination of ethyl sulfate in urine has been demonstrated in human volunteers (3).

 

Also in this case theoretical behavior of the test substance perfectly fits with the experimental data of BMIM Cl. As Urinary excretion of BMIM was the major route of elimination (i.v.: 91% in 24 h; oral: 55–74% of the total oral dose in 24 h). High-pressure liquid chromatography- UV/visible-radiometric analyses of urine samples showed not any peak a single peak that coeluted with the BMIM-Cl standard. This peak was shown to be BMIM by MS/MS analytics.

 

Conclusion

Based on the expected kinetic behavior in the body ad the available data for BMIM Cl, as described above, the test substance will not accumulate in the body after prolonged exposure. The test substance will be systemically bioavailable (ca. 62 %) after ingestion an will be eliminated unchanged via the urine. Dermal Absorption will be low (ca 1%).

 

Additional References 

(1) L. S. Schanker et al. Absorption of drugs from the rat small intestine.J.Pharmacol. Exp.Ther.1958: 123;81-88.

(2)K. K.Rozman,C. D.Klaassen. In: Casarett and Doull's Toxicology, The basic science of poisons, sixth edition. Ed. C. D. Klaassen. Chapter 5: Absorption, distribution and excretion of toxicants 2001.

(3) Helander A, Beck O. Mass spectrometric identification of ethyl sulfate as an ethanol metabolite in humans. Clin. Chem. 2004; 50: 936-7.