Antibiotic loaded chitosan bar - An in vitro, in vivo study of a possible treatment for osteomyelitis

A biodegradable drug delivery system of a gentamicin loaded chitosan bar wi th sustained antibiotic effect is described. Chitosan has proven to be a bi ocompatible aminopolysaccharide and a matrix for controlled release of phar maceuticals. Combined crosslinking, solvent evaporation, and a cylinder mod el cutting technique was used to prepare the chitosan bar. Sustained diffus ion of gentamicin into the surrounding medium was seen using a release test in vitro. Approximately 11% gentamicin was released from the bar in the fi rst 24 hours. The gentamicin released from the bar showed significant antib acterial activity. The bar implanted in the proximal portion of the rabbit tibia produced a low blood concentration of gentamicin, but a much higher c oncentration was produced in local bone and in the hematoma. In all bone ti ssue around the bar, the gentamicin concentration exceeded the minimum inhi bitory concentration for the common causative organisms of osteomyelitis fo r approximately 8 weeks. The implant caused no systemic side effects, Based on these test results together with the chitosan characteristics of biodeg radable, antibiotic, and immunologic activity, the gentamicin loaded chitos an bar seems to be a clinically useful method for the treatment of bone inf ection. This system has an advantage over other systems in that it avoids a second operation for removal of the carrier.