Intestinal Mixed Micelles (IMM)

Intestinal mixed micelles are complex supramolecular aggregates formed in the small intestine during the digestion of dietary fats. They are primarily composed of bile salts, phospholipids, fatty acids, monoglycerides, and cholesterol (StatPearls, NBK525962). Their main biological function is to solubilize hydrophobic lipids and fat-soluble vitamins (A, D, E, and K) in the aqueous environment of the intestinal lumen, facilitating their transport to the brush border membrane of enterocytes for absorption (Vivo Pathophysiology, Bile Acids and Micelles). In clinical pharmacology, these micelles are crucial for the oral bioavailability of lipophilic drugs, which partition into the micellar core to enhance solubility (Journal of Pharmaceutical Sciences, DOI: 10.1002/jps.20382). Drugs like Orlistat interfere with their formation by inhibiting gastric and pancreatic lipases, reducing the availability of fatty acids for micelle assembly (StatPearls, NBK542202). Bile acid sequestrants like Cholestyramine bind to the bile salt components, disrupting the micellar structure and preventing lipid and cholesterol absorption (PubChem, CID 446926). Consequently, they play a significant role in managing conditions like hyperlipidemia and obesity, though their disruption can lead to safety concerns such as steatorrhea and deficiencies in fat-soluble vitamins (NIH, Lipid Digestion and Absorption).

Other names

Mixed micellesBile salt-lipid micellesIntestinal micelles

Bile acid sequestration and disruption of micellar solubilization