In vitro bioactivity and gentamicin release from glass-polymer-antibiotic composites

Composite materials have been prepared from bioactive glass powders in the SiO2-CaO-P2O5 system, a biodegradable polymer [poly(L-lactic acid) (PLA)], a biostable polymer [polymethylmethacrylate (PMMA)], and an antibiotic [gentamicin]. The purpose of such composites is to obtain implantable materials that are able to lead to bone growth and also can, at the most critical inflammation-infection step, release an antibiotic. X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and FTIR analyses after different soaking periods in SBF demonstrated the growth of an apatite-like layer on the composite surface. Therefore the bioactive glass-polymer-antibiotic combination used in this work does not inhibit the glass bioactivity. The release of gentamicin after a soaking of the materials in SBF was followed by UV-visible spectroscopy. A fast initial release during the first 10 h of soaking, followed by a controlled release of the drug was observed. (C) 2000 John Wiley & Sons, Inc.