Mucoadhesive drug delivery system which utilize properties of bioadhesion of certain water-soluble polymers which become adhesive on hydration and hence can be used for targeting a drug to a particular region of the body for extended period of time. The mucosal layer lie a number of regions of the body including the GIT, the urogenital tract, the airways, the ear, nose, mouth and eye. The oral mucosal sites differ greatly from the one another in terms of anatomy, permeability to an applied drug and their ability to retain a delivery system for a desired length of time. The Buccal and sublingual mucosal is relatively, permeable, giving rapid absorption and acceptable bioavailability of drugs and is convenient, easily accessible and generally well accepted Это и многое другое вы найдете в книге Innovation on Optimization of mucoadhesive buccal patch of carvedilol (Kanu R. Patel,N. M. Patel and M. R. Patel)