Lipophilic drug sequestration via "lipid sink" effect

Lipophilic drug sequestration via the "lipid sink" effect refers to the process by which highly fat-soluble (lipophilic) drugs are absorbed or partitioned into a lipid phase, such as an intravenous lipid emulsion (ILE) administered during toxicity, or into artificial surfaces like those found in extracorporeal membrane oxygenation (ECMO) circuits. This mechanism is clinically significant for both drug overdose management and for understanding altered pharmacokinetics in patients on ECMO support. The "lipid sink" theory posits that when a lipid emulsion is introduced into the bloodstream, it creates an expanded intravascular lipid phase. Lipophilic drugs have a high affinity for this phase and are sequestered from plasma and tissues into the lipid droplets. This reduces free drug concentrations at target tissues, thereby reversing toxic effects. In ECMO circuits, lipophilic drugs can be sequestered onto circuit components such as tubing and oxygenators due to their affinity for hydrophobic surfaces.

Partitioning/sequestration of lipophilic drugs into an intravascular/extracorporeal lipid phase ("sink").