Polyvinyl alcohol (PVA) is one of the widely used synthetic polymers for a variety of medical applications. Surface modification of polymers is often used to improve the surface-mediated interactions with the bioenvironment. When phosphate groups are introduced onto the surface of PVA, the modification enhances the hydrophilicity of the polymer. A severalfold enhancement in the extent of uptake of antibacterial drugs such as ampicillin occurs as a result of the phosphorylation. It is also found that drug retention is prolonged significantly by the modification process. Interestingly, the modification did not alter bulk features like the crystallinity of the PVA. (C) 2004 Wiley Periodicals, Inc.