University of Washington has developed a method of crafting medical implants from an antibacterial polymer that could prevent common infections arising from catheters. The polymer, that slowly releases an antibiotic to keep bacteria from establishing a foothold, could be used to prevent infections around commonly used devices as catheters as well as more permanent implants, such as pacemakers. The technology also offers the advantage of preventing development of drug-resistant bugs when some of the bacteria are exposed to an antibiotic and survive.

Catheters, which are used on patients who require a long regimen of intravenous drugs, are initially sterile, but they can become spots where dangerous micro organisms gather. Once the bacteria get on the device, they are extremely difficult to remove and very resistant to treatment, probably due to a protective biofilm that bacteria produce after they become established. When that happens, often the only way to treat the infection is to remove the device from the patient. The key to stopping infections lies in killing bacteria that come near the device before they form an attachment.
To accomplish this, researchers first combined the antibiotic ciprofloxacin with a polymer called polyethylene glycol - an approved food additive, and mixed that with the polyurethane used to make medical implants. That made an even, homogeneous material capable of releasing the drug in a uniform manner. To manage the rate of release, researchers used a plasma process to coat the material with an ultrathin layer of another polymer, butyl methacrylate.
When a device is implanted in the body, fluids pass through that thin, permeable outer coating and dissolve the polyethylene glycol, which makes the polyurethane porous. The antibiotic then leaches out of the polyurethane. The coating acts as a barrier to the antibiotic, controlling the rate at which it is released to the surface of the device. Tests showed that the system maintains a protective drug cloak for at least five days.