Absorption Enhancer
A pharmaceutical excipient or technology that improves drug absorption across biological barriers. SNAC is the absorption enhancer used in oral semaglutide to protect the peptide from stomach acid degradation and promote transepithelial absorption. Absorption enhancers are essential for non-injectable peptide delivery.
Technical Context
Absorption enhancers for oral peptide delivery work through several mechanisms: tight junction modulation (transiently opening paracellular pathways — e.g. sodium caprate, chitosan), transcellular permeation enhancement (increasing membrane fluidity or facilitating transcytosis — e.g. SNAC, medium-chain fatty acids), protease inhibition (co-administered enzyme inhibitors that reduce luminal degradation — e.g. aprotinin, bowman-birk inhibitor), and mucoadhesion (prolonging contact time at the absorption site). SNAC's mechanism for oral semaglutide involves both pH buffering (protecting against pepsin) and transcellular absorption promotion in the stomach. The challenge for all absorption enhancers is achieving sufficient enhancement for therapeutic peptide levels without causing mucosal damage from chronic use.