Gastrointestinal epithelial membrane

The gastrointestinal epithelial membrane serves as the primary physiological barrier to the systemic absorption of orally administered macromolecular drugs, such as peptides, proteins, and nucleic acids. These large, hydrophilic molecules typically suffer from poor bioavailability due to enzymatic degradation in the gut lumen and low permeability across the tightly joined epithelial cells. To overcome this, co-formulated macromolecular APIs utilize permeation enhancers, such as Sodium Salcaprozate (SNAC), which temporarily modify the membrane's properties or facilitate transcellular transport. This approach is exemplified by the oral formulation of the GLP-1 receptor agonist semaglutide, which relies on local pH adjustment and membrane interaction to enable absorption. While effective for delivery, targeting this membrane requires careful management of potential safety risks, such as the non-specific entry of pathogens or toxins during the period of enhanced permeability.

Other names

Intestinal epithelial barrierGI mucosal barrierGut epitheliumIntestinal mucosa

Permeation enhancement via transient disruption of tight junctions (paracellular transport) or facilitation of transcellular lipophilic transport using chemical enhancers like SNAC.