A new polymerizable drug derivative of diclofenac sodium was synthesized and characterized in terms of melting point, elemental analysis, and infrared spectroscopy. It was then polymerized to obtain a new polymeric prodrug. The prodrug was evaluated for its viscosity, drug content, and in vitro drug release behavior at pH 1.2 and 7.2. The in vitro studies showed that the drug release takes place predominantly at the higher pH and in a sustained manner, as hypothesized. Stability at room temperature, bioavailability, and ulcer-inducing effect of the polymeric prodrug were also studied. The investigations showed complete drug absorption from the polymeric prodrug with a statistically significant decrease in ulcer scoring effect, thus showing its potentialfor site-specific and sustained drug delivery.