THE USE OF BIOADHESIVES IN TARGETED DELIVERY WITHIN THE GASTROINTESTINAL-TRACT

Over the last decade or so, bioadhesives have been investigated as potential drug delivery systems for oral administration. It has been envisaged that a delay in gastrointestinal transit time, brought about by an intimate and extended contact between bioadhesive and mucus/mucosal lining, will improve drug bioavailability. This review explores the potential benefits and problems associated with using bioadhesives as targeting vehicles within the gastrointestinal tract. The mucus layer covering the gastrointestinal mucosa presents not only the substrate for adhesion but also the major drawback since the rate of mucus turnover will determine the ultimate success of the dosage form. More recent approaches have involved the use of specific bioadhesives which are capable, at least in vitro, of adhering specifically onto mucosal surfaces. The only way forward may be to develop materials with the potential for greater site-specific attachment to components of the mucosal membrane rather than components of the mucus layer, so that bioadhesion within the gastrointestinal tract can become more of a reality than a dream.