The use of multifunctional polymers for non-invasive peptide and protein application

For the efficient delivery of peptide and protein drugs by non-invasive rou tes various strategies have been pursued to overcome enzymatic and mucosal barriers to gain sufficient bioavailability. Among such delivery systems mu ltifunctional polymers have received considerable attention, which is refle cted by numerous publications and patents. They are able to provide a contr olled release for therapeutic peptides and proteins being embedded in the p olymeric network either based on a simple diffusion process or on the biode gradation of the carrier matrix. Additionally, polymers such as polyacrylat es display an inhibitory effect towards various proteases located on the ab sorption membrane. In combination with enzyme inhibitors, this protective e ffect towards enzymatic attack may further be improved. Moreover, polyacryl ates and chitosan display a permeation enhancing effect, in particular for the paracellular uptake of peptide drugs from mucosal tissues. If these pol ymers also exhibit mucoadhesive properties, the concentration gradient of t he drug on the mucosa can be increased and in the case of oral delivery the presystemic enzymatic degradation of the (poly)peptide drug in the intesti ne between the delivery system and the absorption membrane can be reduced. Delivery systems utilising multifunctional polymers include formulations su ch as nano- and microspheres, pellets and matrix-tablets.