An infection inhibiting urinary catheter material.
Catheter associated bacteriuria is a common infection in hospitals and nursing homes. An infection inhibiting catheter material for fabricating urinary catheters is being developed. The material consists of silicone rubber elastomer compounded with chlorhexidene gluconate (CHG) matrix. The antibiotic is released in sustained fashion over at least 4 weeks. A method was established for adding CHG to silicone rubber. To protect the CHG, it is suspended in a water soluble wax that also modulates CHG release from the elastomer. It was found that CHG is randomly dispersed in the elastomer and that the primary release mechanism is by diffusion. The antibacterial activity of the material with a range of 0.1 to 5% CHG by weight was examined using in vitro zone inhibition testing. The new material demonstrated significant inhibitory activity against three pathogens tested (Escherichia coli, Proteus mirabilis and Staphylococcus epidermidis.). The release rate of CHG was measured in vitro using high performance liquid chromatography (HPLC). With 5% CHG loading, the antibiotic was released at a steady rate of approximately 8.4 mg/cm2/day for periods extending beyond 4 weeks. This new material for urinary catheters has the potential to provide protection against infection and surface colonization.