Polymers with improved 
bioadhesive properties and methods for improving bioadhesion of polymers have been developed. A compound containing an aromatic group which contains one or more hydroxyl groups is grafted onto a 
polymer or coupled to individual monomers. In one embodiment, the 
polymer is a 
biodegradable polymer. In another embodiment, the monomers may be polymerized to form any type of 
polymer, including biodegradable and non-biodegradable polymers. In some embodiments, the polymer is a 
hydrophobic polymer. In the preferred embodiment, the aromatic compound is 
catechol or a derivative thereof and the polymer contains reactive functional groups. In the most preferred embodiment, the polymer is a polyanhydride and the aromatic compound is the 
catechol derivative, DOPA. These materials display 
bioadhesive properties superior to conventional bioadhesives used in therapeutic and diagnostic applications. These 
bioadhesive materials can be used to fabricate new 
drug delivery or diagnostic systems with increased 
residence time at tissue surfaces, and consequently increase the 
bioavailability of a 
drug or a 
diagnostic agent. In a preferred embodiment, the bioadhesive material is a 
coating on a 
controlled release oral dosage formulation and / or forms a matrix in an oral dosage formulation.