Urinary catheters are among the most frequently used medical devices in clinical practice. However, their use is associated with high rates of
nosocomial infection. This study investigates the use of
polyurethane nanocomposites (PUNCs) incorporating an
antimicrobial agent,
chlorhexidine diacetate (CHX), behaving as nanoparticle dispersant and model
drug/active agent, as sustained-release antibacterial
biomaterials in urinary devices. A range of PUNCs incorporating organically modified
silicate (OMS) nanoparticles with CHX was fabricated using a
solution-cast method. PUNCs with free CHX added into the bulk
polymer were also made. Materials were assessed for antibacterial activity in an in vitro urinary tract (UT) model and release kinetics of CHX was studied. PUNCs demonstrated sustained antibacterial activity against Staphylococcus epidermidis in the UT model, reaching ~50 days
infection-free in materials with 2 wt % free CHX loading. Drug-release profiles demonstrated that, compared with microcomposite and unfilled
polyurethane, the initial burst effect was significantly reduced in PUNCs. Prolonged drug release was achieved through incorporation of OMS, hypothesized to be due to a combination of barrier properties created by the nanoinclusions and strong interactions between CHX and
MMT within the PUNCs. Use of PUNCs for sustained drug release in long-term urinary applications shows promise in addressing
catheter-related
nosocomial infections.