Antimicrobial Biodegradable Coating to Reduce Catheter Infection Risk

LONDON -- -- A new biodegradable polymer has potential application in reducing infection associated with the use of implanted medical devices. The development was reported this week to the British Pharmaceutical Conference by researchers from the school of pharmacy at Queen's University Belfast.

Adherence of bacteria to implanted medical devices, such as urinary stents and catheters, can lead to infection, which means that they periodically have to be removed. One way of reducing risk of infection is to coat the device with a biodegradable polymer coating, such that bacteria adhering to the surface are shed as the polymer degrades.

The next step, as reported at the conference, is to provide further protection by incorporating an antibiotic into the polymer coating. This gives a two-pronged attack on adherent bacteria: the release of antibiotic and the degradation of the substrate onto which the bacteria have adhered. Clearly this approach will only work if the addition of antibiotic does not affect the mechanical properties of the coating.

To test this, the Belfast experiments involved incorporation of the antibiotic rifampicin into films of polycaprolactone, a biodegradable polymer that has attracted attention as a coating material for medical devices.

Adding the antibiotic had limited effects on the mechanical properties of the polymer. The researchers concluded: "As the inclusion of rifampicin did not compromise the physicochemical properties of polycaprolactone, this antimicrobial agent may be useful in the design of antimicrobial biodegradable coatings based on this polymer."

Professor David Jones, from the Queen's group, commented, "The challenge ahead is to engineer the rate of degradation to equal the rate of bacterial adherence, thereby effectively cleaning the surface of the device."

Source: The Royal Pharmaceutical Society of Great Britain