Composite Biodegradable Systems for Localized Treatment of Osteomyelitis

Abstract

Osteomyelitis (OM) is a bone infection disease, where Staphylococcus aureus is the main causative micro-organism. OM can result from migration of the micro-organism, spreading of the infectious organism post injury or trauma or due to vascular or neurological insufficiency. OM is characterized by biofilm formation; where few of the organisms are planktonic bacteria that are susceptible for the circulating systemic antibiotics. In fact, most of the pathogens are hardly attached to and embedded within the biofilm. When being sessile in the biofilm, the bacteria are resistant to the defense mechanisms of the host and the systemic antibiotics. By time, the released bacterial toxins and the defense pathways of the host releasing destructive by-products, lead to sepsis, necrosis and edema formation. Conventional treatment strategies of OM include the surgical debridement of the necrotic bone tissues, irrigation with a plenty of antiseptic solution and systemic administration of antibiotics for about 4-6 weeks. The long term administration of intravenous antibiotics is costly, besides; only small portions can reach the bones, and can be associated with systemic adverse effects such as nephrotoxicity, ototoxicity and gastrointestinal adverse effects. In contrary to the systemic administration, local delivery of antibacterial agents offers high local concentrations, hence providing more effective treatment of bone infections and reduced systemic toxicity. Biodegradable systems for intraosseous delivery of antibiotics with high concentrations emerged. These intraosseous delivery systems are able to provide the desired controlled release profiles for bacterial eradication with no or minimum residual antibiotics left in the system, preventing the unfavorable sequences of sub-therapeutic drug levels.