solid oral dosage formulations , such as tablet , mini - tab , multiparticulates or osmotic delivery systems , are coated with a mucoadhesive polymeric coating or formed of a mucoadhesive polymer to increase oral bioavailability of biopharmaceutical classification system class i drugs . representative bcs i drugs include valacyclovir , gabapentin , furosemide , levodopa , metformin , and ranitidine hcl . the inclusion of mucoadhesives in the solid oral dosage form brings the dosage form into close proximity with the target epithelium and facilitates diffusion of drug into intestinal tissue . the mucoadhesive polymer may be either dispersed in the matrix of the tablet or applied as a direct compressed coating to the solid oral dosage form . preferred mucoadhesive polymers include polyanhydride “ p ” and polyanhydride “ p ”. other preferred mucoadhesive polymers include non - erodable polymers such as dopa - maleic anhydride co polymer ; isopthalic anhydride polymer ; dopa - methacrylate polymers ; and dopa - cellulosic based polymers .