Polymer-mucosal adhesive properties

Postulated Mechanisms for Polymer-Mucosal Adhesive Properties... 

The capacity of pathogenic bacteria to adhere to mucosal membranes has been exploited in the modification of new mucoadhesive polymers. The ability of bacteria to adhere to a specific target is rooted from particular cell-surface components or appendages, known as fimbriae, which promote adhesion to other cells or inanimate surfaces. Fimbriae are extracellular, long thread-like protein polymers of bacteria that play a major role in many diseases. It has been reported that Escherichia coli adheres specifically to the lymphoid follicle epithelium of the ileal Peyer s patch in rabbits. Similarly, different staphylococci possess the ability to adhere specifically to the surface of mucus gel layers and not mucus-free surfaces. Thus, polymers have been modified by the attachment of these fimbriae to enhance mucoadhesion. An attachment protein derived from E. coli, K99-fimbriae, has been covalently attached to polyacrylic acid networks in an attempt to provide a novel polymer with enhanced adhesive properties (Figure 52.7). ... 

The failure in increasing residence time of mucoadhesive systems in the human intestinal tract has led scientists to the evaluation of multifunctional mucoadhesive polymers. Research in the area of mucoadhesive drug delivery systems has shed light on other properties of some of the mucoadhesive polymers. One important class of mucoadhesive polymers, poly(acrylic acid) derivatives, has been identified as potent inhibitors of proteolytic enzymes [72-74]. The interaction between various types of mucoadhesive polymers and epithelial cells has a direct influence on the permeability of mucosal epithelia by means of changing the gating properties of the tight jrmctions. More than being only adhesives, some mucoadhesive polymers can therefore be considered as a novel class of multifunctional macromolecules with a number of desirable properties for their use as delivery adjuvants [72,75]. 

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