Intestinal patches with an immobilized solid-in-oil formulation for oral protein delivery

Oral administration of biomolecular drugs such as peptides, proteins, and DNA is an attractive delivery method because of the safety and convenience of delivery in contrast to injection administration. However, oral delivery of biomolecules has several potential barriers such as enzymatic degradation in the gastrointestinal tract and low permeability across an intestinal membrane. In this study, we proposed an intestinal patch system that included surfactant-coated insulin for oral delivery. The intestinal patches, which have mucoadhesive and drug-impermeable layers, induced sustained unidirectional insulin release toward intestinal mucosa and inhibition of insulin leakage from the patches. Moreover, the surfactant-coated insulin, which has high compatibility with cell membranes, enhanced insulin transport across the intestinal membrane. This study demonstrates that the intestinal patches might improve protein permeability in the intestinal mucosa, thereby offering an innovative therapeutic strategy.