Antibacterial Siloxane Polymer Containing Tethered Anti-Microbial Agent (RFT-232)

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Invention Summary


This NDSU invention pertains to the development of a polymer material that exhibits superior sustained release of therapeutic levels of the active antibiotic (levofloxacin) when compared to simple physical bending or doping technologies. The material is prepared by combining a powerful, broad spectrum antibiotic (Levofloxacin), tethered to a siloxane polymer. This invention can potentially be used to coat a variety of biomedically implanted devices for prevention of microbial infection.


  • Superior sustained release of the antibiotic (Levofloxacin)
  • Can be used to coat a variety of medical implants such as artificial joints and heart valves, tracheal tubes, vascular stints, venous and urethral catheters.
  • Levofloxacin is an advanced, broad spectrum fluoroquinolone antibiotic with demonstrated strong activity against a variety of pathogenic gram negative and gram positive bacteria. 

Invention Premise

Artificial devices in contact or implanted within the human body can facilitate transmission of microbial pathogens and cause infection in patients receiving medical treatment. When an infection occurs, it usually results in serious health complications for the patient and the need for an additional surgery to remove the infected device.

Several strategies can be employed to help prevent microbial colonization and infection of medically implanted devices, including systemic administration of antibiotics and coating devices with antiseptic creams and gels. Another approach is to coat the devices with an antibiotic impregnated coating which can extend the antimicrobial lifetime, beyond that of antiseptic creams, and concentrate the activity directly at the site of implantation. The activity of the antimicrobial coating is highly dependent on the sustained release of therapeutic levels of the antimicrobial agent.  Several factors can influence the rate of release of these agents including the local environment (i.e., temperature, pH) and chemistry of the antimicrobial coating material itself (i.e., cross-link density, porosity, water permeability, etc.).

This invention reports the development of a novel antimicrobial siloxane polymer containing the tethered antibacterial agent, Levofloxacin. Polysiloxanes have been used widely for biomedical applications due to their biocompatibility and desirable mechanical properties. As a result, the approach here was to graft Levofloxacin moieties to a polysiloxane using a hydrolytically labile graft. The synthesis was a two-step process in which glycidyl ether groups were first grafted to a polysiloxane copolymer using hydrosilylation chemistry and a portion of the epoxides reacted with Levofloxacin to produce an ester-functional tether. Coatings were prepared from Levofloxacin-functional polysiloxane by solution blending with a multifunctional amine crosslinker.


This technology is the subject of issued US Patent No. 8,071,706 and US Patent No. 8,283,432 and is available for licensing and partnering opportunities.


Henry Nowak, Technology Manager

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