摘要目的 研究内固定表面聚消旋乳酸(PDLLA)结合庆大霉素涂层的体外特性,包括涂层的定量、机械稳定性、无菌性和药物释放特性.方法 应用电子半微量天平和扫描电镜测定涂层的质量与厚度.通过髓腔内的插拔试验确定涂层的机械稳定性.用细菌培养的方法确定涂层过程是否无菌.最后将涂层克氏针浸泡在磷酸盐缓冲溶液中,应用称重法测定涂层在不同时间段的重量损失及用ELISA法测定溶液中释放出的抗生素浓度.结果 涂层的平均重量为(7.2±0.9)mg,涂层的厚度为(13.5±1.7)μm.插拔试验测定涂层的重量损失为(3.5±1.3)%,扫描电镜证明插拔试验后,内固定表面的涂层都是完整、规则的.所有样本在经过血培养及胰蛋白酶培养后均未发现细菌生长.在6周时涂层的重量减少约6.4%.在最初的4 h内庆大霉素呈爆发性释放,之后缓慢而稳定地释放,并且释放可以至少持续6周.结论 内固定表面的PDLLA结合庆大霉素的抗生素涂层具备手术操作所需要的机械稳定性和无菌性.

abstractsObjectives To investigate the characteristics of antibiotic poly(D,L-lactide)(PDLLA)coating of implants,including its quantity,mechanical stability,sterility and antibiotic release in vitro.Methods The weight of the total coating mass was determined with an electronic semimicro balance before and after coating.Thickness of the coating Was documented by scanning electronic microscopy.The stability and the loss of coating mass after implantation and extraction into the intramedullary canal was measured by electronic semimicro balance and the regularity and possible damage of the coating was examined by scanning electronic microscopy.Sterility of the coating procedure was tested by bacteria incubation.A group of coated implants were incubated in PBS to test the coating decrease and the release of gentamicine at difierent time points.Results The quantification of the total coating mass was(7.2±0.9)mg and the thickness of coating was(13.5±1.7)μm.After explantation of the coated implants from the tibia medullary,the mean loss of coating mass Was(3.5±1.3)%.Scanning electronic microscopy confirmed no defects of the coating layer extending to the metallic surface in any implant.None of the tested samples presented bacterial growth after incubation on blood agar and tryptic soy broth.The PDLLA depicted a weight reduction of about 6.4% after 6 weeks.Within the first 4 h.the release of gentamicine experienced an initial peak period,then a constant and gradual release was found for at least 6 weeks.Conclusions The antibiotic PDLLA coating on implants can meet the demands of the mechanical stability and sterility,and gentamicine releases quickly in the first hour and the release can last at least 6 weeks.These characteristics undoubtedly justify the feasibility of the coating usage in clinics.