Prevention of bacterial colonization on polyurethane in vitro by incorporated antibacterial agent

The presence of implanted biomaterials increases host susceptibility to infections. Once established, biomaterial-mediated infections are resistant to treatment and persist until the device is removed. The objective of this work was to study the prevention of bacterial-biofilm formation on polymeric implant (polyurethane) by controlled release of incorporated antibacterial agents (parabens). By embedding parabens in PU by the solvent-cast method, matrices with amorphous dispersions (or solid solutions) were obtained. Release rate modulation was achieved by using different MW parabens and by a rate-limiting membrane. Preliminary in vitro antibacterial studies of both methyl and propyl paraben matrices exhibited significant inhibition of Staphylococcus epidermidis biofilm formation. Propyl paraben matrices (15 and 20% w/w drug load) decreased the number of colony-forming units on PU surface to 2 x 10(4)/mL, in comparison to 6 x 10(5) on control polymers. This significant reduction was obtained without any effect on the number of viable bacteria in the suspension culture. This type of delivery system provides regional prophylactic activity by creating a high local concentration of antibacterial agent.