局部缓释药丸防治开放性骨折感染的实验研究.doc

局部缓释药丸防治开放性骨折感染的实验研究更新日期：2010-09-08 吴宏斌郑启新徐逢仁李世谱刘畅阎玉华 【摘要】目的局部植入缓释药丸防治开放性骨折骨及软组织感染。方法用可降解人工骨移植材料磷酸三钙承载第三代喹喏酮类广谱抗生素环丙沙星制成磷酸三钙/环丙沙星缓释药丸(TCDC)并检测其体外抑菌能力及植入兔股骨大转子后释药情况。结果TCDC对金葡菌、大肠杆菌、绿脓杆菌等骨科感染常见致病菌有强大且持久的抑菌能力,持续时间分别大于5、51天,等于27天。TCDC周围骨及肌肉组织能长期(大于30天)保持较高药物浓度,而血中浓度极低且呈逐渐下降趋势。结论TCDC具有防治开放性骨折感染的良好前景。 【关键词】磷酸三钙环丙沙星骨折,开放性感染 Experimental Study on Local Drug Delivery System for Treatment of Open FracturesWU Hong-bin, ZHENG Qi-xing, XU Feng-ren, et al. Emergency Center of Union Hospital, Tongji Medical University, Wuhan 430022 【Abstract】AimDrug delivery system (DDS) was adopted for the prophylaxis and treatment of osteomyelitis and soft tissue infection after open fractures. MethodsWe prepared a new DDS, tricalcium phosphate/ciprofloxacine delivery capsule (TCDC) by loading broadspectrum antibiotic: ciprofloxacine into the cylindrical cavity of biodegradable bone substitute tricalcium phosphate (TCP) and TCDCS bacteriostasis ability in vitro and in vivo were also tested. ResultsTCDC showed great and lasting bacteriostasis to common pathogens of orthopaedic infections, such as staphylococcus aureus, escherichia coli and pseudomonas aeruginosa, with bacteriostasis lasting more than 5 days, 51 days and 27 days respectively. In vivo study showed that high concentration of ciprofloxacine still occurred in the bone and muscle tissues surrounding TCDC which was placed in the great trochanter of rabbit and that it continued to let off ciprofloxacine for at least 30 days, while the concentration of ciprofloxacine in blood was very low and tended to reduce gradually. ConclusionTCDC can sustain a high local antibiotic concentration while the blood antibiotic concentration is very low. It may become a good method to treat infections after open fractures. 【Key words】Tricalcium phosphateCiprofloxacineOpen fractureInfection 开放性骨折较易并发软组织感染及骨髓炎,严重感染常会影响骨折愈合。如何防治这类感染,一直是临床医师颇为关切的问题。Henry等将载抗生素的聚甲基丙烯酸甲酯(polymethylemethacrylate, PMMA)药丸置入骨折部,在临床上取得了良好的防治感染效果1。Rethman则用聚乙烯酸/聚乳酸共聚物(polyglycolic acid/polylactic acid copolymer)承载抗生素治疗鼠股骨干骨折合并金葡菌感染,亦获成功2。笔者用磷酸三钙承载广谱抗生素环丙沙星制成磷酸三钙/环丙沙星缓释药丸(tricalciurm phosphate/ciprofloxacine delivervy capsule, TCDC),并对其体内、外的释药情况进行了研究。 材料与方法 一、TCDC的制备 分析纯CaHPO4.2H2O和CaCO3粉末按一定比例充分混匀后,常压下升温致960,保温2小时再冷却成TCDC原料粉备用。选择以P2O5-CaO为主要成份的低融点玻璃为高温粘结剂,以重量比为167的比例与TCDC原料粉充分混匀、烘干,再加入40%左右溶融的石蜡作为成孔剂,充分拌合后,注入药囊模具成型,药丸分中空圆柱状主体和尾盖两部分(图1)。药丸内径2mm、长8mm、壁厚1mm。将成型后的坯体放入高温炉内埋烧,排蜡和烧成一次完成。排蜡在200500间进行,烧成温度为900,在900保温2小时后随炉冷却,将烧成的药丸装载8mg盐酸环丙沙星药粉,并用-磷酸三钙骨水泥(-TCP)将尾盖与主体封合在一起。 图1TCDC药丸分中空圆柱状主体与尾盖两部分,装药后用-TCP骨水泥封合在一起 二、体外抑菌实验 将160高温消毒2小时的TCDC3粒,在无菌操作下分别置于接种有金葡菌、绿脓杆菌、大肠杆菌的琼脂培养基中央;另用160高温消毒2小时未装药的TCP空药丸,亦分别置于接种有上述3种细菌的培养基中央作为对照。实验组及对照组培养基均置于37温箱。24小时后记录抑菌情况。72小时后将所有TCDC及TCP空药丸重新转入新的接种有相应菌种的培养基中,置37温箱,继续观察抑菌情况,如此反复转培17次,共观察57天。上述所有标准菌种为同济医科大学附属协和医院检验科提供。 三、体内释药实验 1.同济医科大学动物中心提供的大耳白兔8只(雌兔5只、雄兔3只),体重22.5kg。846合剂肌肉麻醉后,于无菌条件下手术暴露双侧股骨大转子,每侧钻两个直径4mm,深67mm的骨腔,两腔相距约2mm,每个骨腔植入TCDC1粒。TCDC约3/4植入骨腔内,约1/4留于腔外用肌肉组织包裹。每侧股骨转子区植入TCDC2粒,双侧共4粒。植入后1、2、3、4、5、7、9、12天从兔耳缘静脉采血2ml,并于第9、16、23、30天分别处死兔2只。处死前耳缘静脉采血2ml,处死后取紧邻植入体的骨和肌肉各500700mg。用日本岛津公司产HPLC-型高效液相色谱仪检测血及组织中环丙沙星浓度。 2.将植入兔股骨转子区30天后的TCDC取出,置入接种有金葡菌的琼脂培养基中央,37温箱培养24小时后观察抑菌情况。 结果 一、扫描电镜观察TCP载体材料的横断面形貌 图2可见载体壁具有分布均匀的连通气孔。图3可见清晰的连通气孔。孔壁晶体发育不均匀,多为不规则形。测量气孔孔径一般在30m左右。 图2TCDC壁具有分布均匀的连通气孔,药物微粒通过 这些微孔缓慢释出SEM1000 图3TCDC壁中,孔壁晶体发育不均,多不规则, 测量孔径一般在30m左右SEM5000 二、体外抑菌实验结果 实验组TCDC有明显抑菌圈,对照组TCP载体材料无抑菌作用,每种细菌的抑