A biodegradable suction patch for sustainable transbuccal peptide delivery

Despite considerable advances in the systemic delivery of peptides, their susceptibility to gastrointestinal degradation and high molecular weight, which restricts permeability across biological barriers, remain obstacles to oral administration. As a result, most peptide therapies rely on injections to achieve therapeutic effects. Recent studies on a bioinspired suction patch demonstrated positive effects in vivo with three peptides - desmopressin, semaglutide, and teriparatide - yet materials used for patch fabrication were non-degradable. In this work, a more sustainable patch alternative is introduced by replacing previously used materials with biodegradable polymers, aiming for degradation of the patch after removal to reduce environmental impact. A scalable mold casting process was employed to thermally crosslink synthesized and functionalized copolyesters, yielding the desired devices. Mechanical testing across various materials and shapes identified the best-performing polymer, while its degradation was confirmed in both aqueous medium and simulated waste. An ex vivo model using porcine buccal tissue validated the functionality of biodegradable patches, showing enhanced permeation of a poorly permeable dye when combined with a chemical permeation enhancer. In beagle dogs, the bioavailability of semaglutide (4.11 kDa) was substantially improved compared to the commercially available tablet, with an application time of only 10 min. Additionally, the patch achieved a relative bioavailability of 26% for bremelanotide (1.03 kDa) compared to subcutaneous administration. This work underscores the potential of replacing silicone devices with biodegradable alternatives, providing a more sustainable approach for peptide delivery via the buccal suction patch.