The objective in this study was to develop an osteoconductive, biodegradable and
rifampicin releasing bone filling composite material for the treatment of
osteomyelitis, a
bacterial infection of bone that is very difficult and expensive to treat. The composite material will be used together with a
ciprofloxacin releasing composite, because of the rapid development of resistant bacteria when
rifampicin is used alone. Three composites were manufactured by twin-screw extrusion. The
polymer matrix for the composites was
poly(L-lactide-co-ε-
caprolactone) 70/30 and all the composites contained 8 wt% (weight percent) of
rifampicin antibiotic. The β-TCP contents of the composites were 0 wt%, 50 wt% and 60 wt%. The composites were sterilized by gamma irradiation before in vitro degradation and drug release tests. The hydrolytical degradation of the studied composites proceeded quickly and the molecular weight of the
polymer component of the composites decreased rapidly.
Rifampicin release occurred in four phases in which the high β-TCP content of the samples,
polymer degradation and mass loss all played a role in determining the phases. The ceramic component was seen to have a positive effect on the drug release. The composite with 50 wt% of β-TCP showed the most promising
rifampicin release profile and it also showed activity against a common
osteomyelitis causing bacteria Pseudomonas aeruginosa. A clear inhibition zone was formed in 16 h incubation. Overall, the tested materials showed great potential to be developed into a bone filler material for the treatment of
osteomyelitis or other bone related
infections in combination with the
ciprofloxacin releasing materials.