BIODEGRADABLE IMPLANTS FOR POTENTIAL USE IN BONE INFECTION - AN IN-VITRO STUDY OF ANTIBIOTIC-LOADED CALCIUM-SULFATE

Local antibiotic therapy by diffusion from plaster of Paris beads has proved promising in bone surgery. Sustained local delivery depends on thermostability, so we tested the antibacterial activity of 11 antibio tic solutions after storage at 37 degrees C using a microbiological me thod. Cephalosporins and penicillins were unstable, but aminoglycoside s remained fully stable with 100% activity after 2 weeks. About 60% of the initial bactericidal activity of quinolone, glycopeptides and sod ium fusidate were still detectable after 2 weeks. Release of these ant ibiotics from plaster of Paris beads was evaluated in vitro. Even thos e in the same family differed in their release rate. Plaster beads wit h sodium fusidate were the most effective association. A therapeutic l evel of glycopeptides, aminoglycosides and amoxicillin was leached for about 3 weeks. Cephalosporins and sodium amoxicillin were released in 2 to 3 days, and quinolone bends were too brittle to be used. Plaster of Paris, which is cheap, biocompatible and biodegradable, is an exce llent carrier for sodium fusidate, aminoglycosides and glycopeptides.