In this study, the diffusion characteristics of diclofenac-Na through hydrophobic and hydrophilic polyurethane (PU)-based membranes are investigated. Hydrophilic polymers are obtained by g-raft copolymerization of PU with acriylamide (AA-m) and itaconic acid (IA), The membranes are prepared by a solvent-casting method and characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis. The diffusion measurements are performed using a diffusion cell for 10 h at 37degreesC. Permeability coefficients calculated from diffusion experiments are similar to3 times higher in hydrophilic membranes than hydrophobic PU membranes.