Interactions of Epinephrine and Norepinephrine with Intralipid Emulsion Studied by Capillary Electrokinetic Chromatography

Epinephrine and norepinephrine are widely used to treat cardiovascular collapse during resuscitation with lipid emulsions in the treatment of drug toxicity including local or non-local anesthetics. The effect of the lipid emulsion Intralipid on the vasoconstriction induced by epinephrine or norepinephrine is, however, still unknown. In this study, the interaction of epinephrine and norepinephrine with the intravenous Intralipid emulsion was investigated by capillary electromigration techniques. Capillary electrokinetic chromatography was performed to determine the distribution coefficients by running the analytes under different experimental conditions (temperature, ionic strength, and pH) through a capillary filled with the background electrolyte containing Intralipid emulsion. In addition, the binding constants of the epinephrine and norepinephrine complexes with Intralipid emulsion were determined based on the effective electrophoretic mobility data obtained by electrokinetic chromatography at a wide concentration range of Intralipid emulsion. The obtained binding constants, as well as the distribution coefficients determined by electrokinetic chromatography, confirm that epinephrine and norepinephrine are hydrophilic compounds and that they are minimally distributed into the Intralipid emulsion. Therefore, their application as drugs for vasoconstriction upon Intralipid emulsion treatment is well motivated.