Experimental Study on the Intraosseous Implantation of the Bioceramics Containing Antibiotics

Abstract

Development of implant, which not only fills a bone defect, but very slowly releases an antibiotic and also provides the base for osteogenesis, is a very important clinical task. The purpose of this study is to obtain fundamental data necessary to develop such implant. Namely, we prepared combination implants using gentamicin (GM), polylactic acid(PLA), and hydroxyapatite(HAP), and then examined slow release of GM in vitro and effects on such sustained release and osteogenesis in vivo. Five kinds of implants were prepared and used in experiments. Implants were statically placed in a water bath at 37℃ in vitro ; each implant was implanted in a tibia of white rabbit in vivo. As a result, the most satisfactory results were obtained from implants of group E ; namely, these implants, containing 20mg HAP, 10mg GM, and 20mg PLA, were prepared as follows ; they were compressed, and then melted at 120℃ and cooled in teflon tubes for curing. In group E, GM was very slowly released in vitro over 2 months; GM was also released very slowly in vivo at a level exceeding MIC for 5 weeks, and a bone cortex defect was covered with an osteogenetic layer 6 weeks after implantation.