几丁糖庆大霉素局部药物释放系统的临床应用研究

对几丁糖庆大霉素局部药物释放系统治疗慢性骨髓炎的疗效及体内动力学行为进行研究，为其临床推广应用提供理论依据。采用外科病灶清除术后残腔内置入几丁糖庆大霉素缓释药治疗慢性骨髓炎１８例。监测术后不同时间庆大霉素血药浓度，血尿素氮（ＢＵＮ）和肌酐（Ｃｒ）值，局部引流液中庆大霉素浓度。以术后切口愈合情况、临床表现和Ｘ线片评定疗效。结果，血药浓度峰值（０．８３μｇ／ｍｌ）在２４小时出现，维持时间为４天；术后ＢＵＮ和Ｃｒ值无增加；术后局部引流液中庆大霉素浓度为金黄色葡萄球菌最低抑菌浓度数百倍。１８例患者均获随访，随访时间６个月～３４个月，平均２４．８个月。初期愈合１６例，无一例复发。认为，几丁糖庆大霉素缓释药是临床治疗慢性骨髓炎的有效方法，具有简便安全，且无需二期取出载体的优点，为临床推广应用提供了理论依据。     

几丁糖庆大霉素药物释放系统的研制及体外释放实验

目的：研制几丁糖庆大霉素药物释放系统（ｄｒｕｇｄｅｌｉｖｅｒｙｓｙｓｔｅｍ，ＤＤＳ）并为骨感染治疗提供新的简便方法。方法：在几丁糖胶体中加入庆大霉素，经化学修饰交联、模具分割、干燥等工艺形成ＤＤＳ棒。对ＤＤＳ药棒进行重量、大小、含药量、机械性能测试和抑菌实验、体外释放实验研究。结果：ＤＤＳ棒大小、重量及含药量差异小，浸泡无脆裂。庆大霉素具有生物活性，体外释放实验显示第１天释放量为９２６．７μｇ／颗，其后下降并以较低水平稳定释放，约４．０μｇ／颗／天，维持时间在２５天以上。结论：几丁糖ＤＤＳ具有工艺稳定、不易脆裂，庆大霉素生物活性无破坏及良好的体外缓释作用，可望为骨感染的治疗提供新的手段。     

几丁糖阿霉素缓释药粒的体外实验研究

几丁糖是一种无毒、无副作用，生物相容性良好，可在体内自然降解吸收的生物材料。利用几丁糖缓慢降解的特性，将其与阿霉素制成几丁糖阿霉素缓释药粒，并进行体外释放试验及其浸出液的体外抑制ＯＳ－１１６骨肉瘤试验。结果表明，该缓释药粒可使阿霉素呈缓慢稳定的释放，其第１，２０，４０及６０天浸出液的ＯＳ－１１６骨肉瘤的抑制率分别为５８．１１％，３６．４８％，２４．３２％及２１．６２％。认为，几丁糖与阿霉素制成的缓释药粒具有良好的缓释功能，且不影响阿霉素的活性，是化疗药物缓释的极好载体，并可应用于骨肿瘤术后的局部治疗。     

可塑形抗感染纳米羟基磷灰石药粒的研制及体外释放的实验研究

目的研制可塑形抗感染纳米羟基磷灰石(nano-HA)缓释药粒,为骨髓炎的治疗提供一种新型的局部药物缓释系统(LDDS)。方法采用nano-HA为载药核心载体,外包裹生物相容性好且可降解的聚羟基丁酸酯-羟基戊酸酯共聚物/聚乙二醇(PHBV/PEG),承载硫酸庆大霉素(GM)制成nano-HA-PHBV/PEG-GM缓释微球,复合nano-HA-PHBV/PEG-GM缓释微球与纤维蛋白凝胶(FS)研制出一种可塑形LDDS,研究其抑菌作用及体外释药特性。结果可塑形LDDS药粒有明显的抑菌圈,对金黄色葡萄球菌的抑菌作用长达56d,体外释放实验显示第1天释放量为154.3μg/mL,其后下降并以较低水平稳定释放,维持有效释药时间在49d以上。结论可塑形抗感染nano-HA药粒具有良好的体外缓释作用,操作简便,可预塑成各种形状的特点,为治疗骨髓炎提供了一条有效的治疗途径。     

几丁糖预防肘关节粘连的临床研究

目的　研究医用几丁糖预防肘关节粘连的临床作用。方法　对 2 6例肘关节僵硬患者进行手术松解 ,其中 12例术后关节腔内涂布 2 %几丁糖 ,另 14例术后不用几丁糖作为对照组 ,观察术后肘关节伸屈活动度改善程度以评定疗效。结果　 2 6例均获随访 ,随访时间 8～ 5 1个月 ,平均 2 4个月。几丁糖组术后肘关节平均活动度恢复到 92 .9°± 2 0 .9°,比术前增加 5 5 .0°± 15 .9°;对照组术后肘关节平均活动度恢复到 75 .4°± 17.5°,比术前增加38.2°± 11.9°。几丁糖组术后肘关节伸屈活动度增值明显大于对照组 ,有显著性差异 (P<0 .0 1)。结论　医用几丁糖具有减轻或预防肘关节松解术后再粘连的形成。     

几丁糖薄膜对肌腱粘连及愈合影响的实验研究

目的　研究几丁糖薄膜对肌腱粘连和愈合的影响,为临床应用几丁糖薄膜预防肌腱术后粘连提供实验依据。方法　以55 只6～8 个月来亨鸡的趾深屈肌腱为实验模型,将切断的趾深屈肌腱周围包裹几丁糖薄膜,术后2、4、6、8和10 周分别测量肌腱的活动或抗张强度,肉眼及病理切片观察肌腱的粘连、愈合情况。结果　几丁糖薄膜能有效预防肌腱粘连,早期(即4 周内)可以影响肌腱愈合,4 周后可加快肌腱愈合和增加肌腱抗张强度。结论　几丁糖薄膜具有无毒副作用、生物通透性好及生物降解、吸收好,并可以选择性抑制成纤维细胞生长等优点,能有效预防肌腱粘连,晚期(4 周后)可加快肌腱愈合,是一种较为理想的预防肌腱粘连的生物材料     

几丁糖预防髌骨骨折术后膝关节粘连的临床观察

目的　观察几丁糖对髌骨骨折术后发生膝关节功能障碍的影响。方法　选择 1999年 3月～ 1999年10月收治的 4 0例髌骨骨折行内固定治疗者 ,随机选择 2 4例术中关节腔内涂布 2 %几丁糖 4 ml作为几丁糖组 ;另 16例常规手术不作任何处理作为对照组。双盲法观察术后 1个月和 1年时膝关节的伸屈活动度。结果　 4 0例均获随访 ,术后 1个月时膝关节活动度 ,几丁糖组伸屈 10 4°± 2 3°,对照组伸屈 72°± 16°,具有统计学意义 (P<0 .0 1) ;术后 1年 ,几丁糖组伸屈 16 5°± 38°,对照组 110°± 31°,具有统计学意义 (P<0 .0 5 )。结论　医用几丁糖能有效预防髌骨骨折术后膝关节粘连的发生。     

载利福喷丁/聚乳酸-聚乙醇酸共聚物微球制备及体外释放

目的：制备可用于持续抑制脊柱结核术后病灶残留结核分枝杆菌的载利福喷丁／聚乳酸-聚乙醇酸共聚物[ Poly（ lactic-co-glycolic acid）, PLGA]微球,并研究其体外释放性能。方法通过乳化-溶剂挥发法制备载利福喷丁／PLGA微球,光学显微镜和扫描电镜观察微球形貌,激光粒度分布仪测定微球粒径及分布,紫外分光光度计测定微球载药量及包封率。检测利福喷丁抗结核分枝杆菌的最低抑菌浓度,并以pH＝7．4的PBS缓冲溶液为释放介质,紫外分光光度计检测载药微球体外释放特性。结果载利福喷丁／PLGA微球成球形状良好,表面光滑,分散性好,粒径分布均匀,平均粒径为25．49μm。载药量及包封率分别为21．37％±0．16％和74．79％±2．71％。体外释放实验显示在突释期内,利福喷丁释放量占载药微球中药物含量的37．08％±1．68％;在缓释期内载药微球释药速度减慢,第5周释放量仍超过利福喷丁抗结核分枝杆菌的最低抑菌浓度,35 d后体外累积释放量为80．67％±0．97％,仍高于利福喷丁抗结核分枝杆菌的最低抑菌浓度2μg／mL。结论 PLGA是一种理想的控缓释材料,所制备的载利福喷丁／PLGA微球具有良好的控释效果,是一种有效的抗结核缓释剂型。     

利福平和几丁糖对慢性骨髓炎的影响

目的 报告利福平（ＲＦＰ）和几丁糖治疗慢性骨髓炎的临床疗效。方法 根据患者年龄、肝脏功能、症状体征以及Ｘ线片改变来确定ＲＦＰ与几丁糖的日服量和治疗总量。结果 本组病例随访时间平均２７月,临床愈合２３例,有效２例,无效３例。结论 ＲＦＰ与几丁糖联合应用能增强抗菌效力,减少ＲＦＰ对肝脏和强化肝脏机能以及提高机体免疫力。     

几丁糖联合带线锚钉Kessler缝合法治疗急性跟腱断裂

目的探讨几丁糖联合带线锚钉Kessler缝合法治疗急性闭合跟腱断裂的临床疗效。方法将34例患者按治疗方法分为两组,采用几丁糖联合带线锚钉Kessler缝合法修复为A组(17例),单纯Kessler缝合法修复为B组(17例)。对两种缝合方法进行临床疗效评价。结果患者手术切口均一期愈合。患者均获得随访,时间12~18个月。手术时间、术中出血量A组明显少于B组,差异均有统计学意义(P0.05);切口并发症、切口愈合时间两组比较差异均无统计学意义(P0.05);末次随访AOFAS评分、踝关节背伸及跖屈范围、末次随访患者满意度及疗效优良率A组均优于B组(P0.05)。结论几丁糖联合带线锚钉Kessler缝合法治疗急性跟腱断裂操作简便,疗效满意。     

Antibiotic loaded chitosan bar. An in vitro, in vivo study of a possible treatment for osteomyelitis

A biodegradable drug delivery system of a gentamicin loaded chitosan bar with sustained antibiotic effect is described. Chitosan has proven to be a biocompatible aminopolysaccharide and a matrix for controlled release of pharmaceuticals. Combined crosslinking, solvent evaporation, and a cylinder model cutting technique was used to prepare the chitosan bar. Sustained diffusion of gentamicin into the surrounding medium was seen using a release test in vitro. Approximately 11% gentamicin was released from the bar in the first 24 hours. The gentamicin released from the bar showed significant antibacterial activity. The bar implanted in the proximal portion of the rabbit tibia produced a low blood concentration of gentamicin, but a much higher concentration was produced in local bone and in the hematoma. In all bone tissue around the bar, the gentamicin concentration exceeded the minimum inhibitory concentration for the common causative organisms of osteomyelitis for approximately 8 weeks. The implant caused no systemic side effects. Based on these test results together with the chitosan characteristics of biodegradable, antibiotic, and immunologic activity, the gentamicin loaded chitosan bar seems to be a clinically useful method for the treatment of bone infection. This system has an advantage over other systems in that it avoids a second operation for removal of the carrier.     

壳聚糖化疗药物缓释药粒局部治疗骨巨细胞瘤的实验研究

目的 探讨骨巨细胞瘤化疗的可行性及确定生物可降解材料壳聚糖作为其治疗的药的载体的可能性。方法 体外培养骨巨细胞瘤标本,测定药物及壳聚糖的敏感性;将壳聚糖与化疗药制成缓释药粒,进行体外及体内释放试验。结果 骨巨细胞瘤对阿霉素（ＡＤＭ）、顺氨氯铂（ＣＤＤＰ）中度敏感。单纯壳聚糖对骨巨细胞瘤在体外无抑制作用。体外及体内试验第１ｄＡＤＭ释放量较大,其后在较低水平维持相对稳定的缓慢释放达８周以上。结论 骨巨     

Locally administered antibiotics for prophylaxis against surgical wound infection. An in vivo study

BACKGROUND: Currently, the standard for prophylaxis against surgical infection consists of perioperative systemic antibiotics. In this study, we investigated the relative efficacy of various methods of antibiotic delivery for the prevention of surgical wound infections. We hypothesized that sustained release of local antibiotics inside the wound cavity by a drug delivery system would be more effective than systemically administered antibiotics. METHODS: Using a rat model, we inoculated a surgical wound in the quadriceps muscle with 8.0 x 10(5) colony-forming units of Staphylococcus aureus and then administered one of seven types of treatment: no treatment (control), bacitracin irrigation, calcium sulfate flakes, systemic gentamicin, local aqueous gentamicin, local gentamicin-loaded calcium sulfate flakes, and a combination of local gentamicin-loaded calcium sulfate and systemic gentamicin. The seven treatment groups consisted of ten rats each. To further evaluate a trend, the group treated with systemic gentamicin and the one treated with local gentamicin solution were extended to include twenty-five and twenty-seven rats, respectively. At forty-eight hours postoperatively, specimens from the wounds were obtained for quantitative culture. RESULTS: The control group, the group treated with bacitracin irrigation, and the one treated with plain calcium sulfate had very high bacterial counts and high mortality rates while the groups treated with gentamicin had low bacterial counts and a 100% survival rate. Local gentamicin was significantly more effective than systemic gentamicin in reducing bacterial counts. CONCLUSIONS: The gentamicin-loaded calcium sulfate flakes did not result in bacterial counts that were significantly lower than those following systemic administration of gentamicin, which refuted our hypothesis. However, gentamicin solution injected directly into the closed wound did result in levels of bacteria that were significantly lower than those following treatment with the systemic gentamicin.     

Antimicrobial release kinetics from polymethylmethacrylate in a novel continuous flow chamber

Polymethylmethacrylate is used for local delivery of antimicrobials in the treatment of musculoskeletal infections. A novel continuous flow chamber system was designed to measure in vitro antimicrobial release. Three-millimeter beads containing amikacin, gentamicin, tobramycin, or vancomycin [concentration of 7.5% (weight per weight)] were placed individually in a continuous flow chamber with a total volume of 1 mL Kreb's Ringer buffer flowing at 1 mL/hour. Effluent was sampled hourly for 24 hours and then every 2 hours up to 48 hours; antimicrobial concentrations were measured in triplicate by bioassay. The mean peak concentrations were 40.9, 30.1, 30.0, and 19.1 microg/mL; the mean areas under the concentration time curves (Time 0 to infinity) were 263, 327, 110, and 180 hours x microg/mL of antibiotic; and the mean percentages of initial amount of antimicrobial released were 11.7%, 14.5%, 6.6%, and 10.9% for tobramycin, gentamicin, amikacin, and vancomycin, respectively. The results for each polymethylmethacrylate-antimicrobial agent combination were reproducible. In contrast to other in vitro elution systems, this novel system operates under the premise that there is dynamic flow surrounding polymethylmethacrylate in vivo and permits rapid in vitro comparison of the relative release of antimicrobial agents from polymethylmethacrylate.     

复合庆大霉素抗生素骨制备及其治疗感染性骨缺损的实验研究

目的研制一种既有成骨作用,又有抗感染能力,且免疫原性较低的新型植骨材料。方法以5mm×5mm×5mm骨粒和6mm×6mm×20mm骨条作为载体,采用超声和负压双重复合法制备复合庆大霉素抗生素骨粒和骨条。将抗生素骨粒分别埋入24只Wistar大鼠左、右股肌袋内,于术后1、3、5、7、10和14d检测庆大霉素体内释药浓度及持续时间。将健康雄性成年绵羊10只,制成6mm×6mm×20mm左前肱骨和右后股骨缺损感染模型,于缺损处注入5×1010CFU/ml金黄色葡萄球菌1ml。将感染动物随机均分为实验组和对照组(n=5),实验组将复合庆大霉素抗生素骨条植入缺损区,对照组将空白骨条植入缺损区。术后行大体观察、白细胞计数、X线片及组织学观察。结果大鼠抗生素骨粒植入后1d,骨粒与肌肉组织中药物浓度分别为46.1μg/ml和17.3μg/ml,后缓慢释放,至14d局部软组织药物浓度仍高于金黄色葡萄球菌最小抑菌浓度(<2.0μg/ml)。羊体内抗感染实验术后2周,实验组1只羊1侧肢体植骨部位出现脓性分泌物,4~8周植入骨与周围较好融合,12周愈合良好;对照组2~8周植入骨基本被脓液包裹或软组织取代,其中1只羊于20d死亡,12周植骨区除中央被软组织填充外,余愈合较好。白细胞计数术前各组均在正常生理范围,术后1~14d实验组白细胞计数均低于对照组。X线片和组织学观察显示,实验组术后2周除1侧肢体植骨腔内出现脓液,余在各周内逐渐有新骨生成并爬行取代植入骨,愈合良好;对照组2~8周显示植入骨被脓液包裹,并逐渐被吸收,未见新生骨爬行取代。结论复合庆大霉素抗生素骨具有较好的缓释特性、体内抗感染效果和成骨能力,有望成为治疗感染性骨缺损的一种较理想的骨植入材料。     

可塑性纳米羟基磷灰石/聚羟基丁酸酯-羟基戊酸酯共聚物-聚乙二醇庆大霉素释药系统研制

目的研制可塑性纳米羟基磷灰石/聚羟基丁酸酯-羟基戊酸酯共聚物-聚乙二醇[nano-hydroxyapatite/poly(3-hydroxybutyrate-hydroxyvalerate)-polyethyleneglycol,nano-HA/PHBV-PEG]庆大霉素(gentamicin,GM)局部药物释放系统(drugdeliverysystem,DDS),为治疗骨髓炎提供一有效方法。方法以纤维蛋白胶为微球支架,nano-HA为GM载药核心,外包裹PHBV及PEG,制成可塑性nano-HA/PHBV-PEG-GM-DDS。电镜观察nano-HA、载药nano-HA和载药nano-HA/PHBV-PEG微球形貌特征。将可塑性nano-HA/PHBV-PEG-GM-DDS植入36只新西兰大白兔股骨内,术后12个不同时间点K-B法检测其血液、皮质骨和松质骨GM浓度,评价可塑性nano-HA/PHBV-PEG-GM-DDS体内释药效果。结果nano-HA呈短棒状,长度<60nm。载药nano-HA呈晶体自然凝聚状态,表面吸附大量GM,平均粒径为200.5nm。载药nano-HA/PHBV-PEG微球表面形态一致,为多孔皱缩结构,平均粒径为34.5μm。GM浓度与抑菌环直径呈线性相关,相关系数为0.998。术后第1天可塑性nano-HA/PHBV-PEG-GM-DDS周围皮质骨和松质骨中GM浓度分别为95.50±16.50μg/ml和80.20±13.80μg/ml,其后逐渐下降,致第56天时为5.60±1.60和5.10±1.30μg/ml,高于GM对金葡菌的最低抑菌浓度(2μg/ml)。结论可塑性nano-HA/PHBV-PEG-GM-DDS具有较好的体内缓释作用,临床上对于骨髓炎的治疗有应用前景。     

In vitro testing of chitosan in gentamicin-loaded bone cement No antimicrobial effect and reduced mechanical performance

Background and purpose?Efforts to prevent infection of arthroplasties, including the use of antibiotic-loaded bone cement, are not always successful. We investigated whether the incorporation of chitosan in gentamicin-loaded bone cement increases antibiotic release, and prevents bacterial adherence and biofilm formation by clinical isolates of Staphylococcus spp. In addition, we performed mechanical and degradation tests.

Methods?Different amounts of chitosan were added to the powder of the gentamicin-loaded bone cement. Gentamicin release was determined using high-per-formance liquid chromatography mass spectrometry. Bacterial adherence and bacterial biofilm formation were determined using clinical isolates cultured from implants retrieved at revision hip surgery. The mechanical properties were determined as a function of degradation in accordance with ISO and ASTM standards for PMMA bone cement.

Results?The addition of chitosan to bone cement loaded with gentamicin reduced gentamicin release and did not increase the efficacy of the bone cement in preventing bacterial colonization and biofilm formation. Moreover, the mechanical performance of cement containing chitosan was reduced after 28 days of degradation. The compressive and bending strengths were not in compliance with the minimum ISO and ASTM requirements.

Interpretation?Clinically, incorporation of chitosan into gentamicin-loaded bone cement for use in joint replacement surgery has no antimicrobial benefit and the detrimental effect on mechanical properties may have an adverse effect on the longevity of the prosthetic joint.     

Antimicrobial efficacy of gentamicin-loaded acrylic bone cements with fusidic acid or clindamycin added.

The increasing gentamicin resistance among bacteria in septic joint arthroplasty has stimulated interest in adding a second antibiotic into gentamicin-loaded bone cement. A first aim of this in vitro study is to investigate whether addition of fusidic acid or clindamycin to gentamicin-loaded bone cement has an additional antimicrobial effect against a collection of 38 clinical isolates, including 16 gentamicin-resistant strains. A modified Kirby-Bauer test, involving measurement of the inhibition zone around antibiotic-loaded bone cement discs on agar plates, was used to investigate whether adding a second antibiotic has an additional antimicrobial effect. Second, a selected number of strains was used to study their survival in an interfacial gap made in the different bone cements to mimic the gap between bone and cement as existing near a prosthesis. Gentamicin-loaded bone cement had an antimicrobial activity against 58% of the 38 bacterial strains included in this study, while 68% of the strains were affected by bone cement loaded with a combination of gentamicin and clindamycin. Bone cement loaded with the combination of gentamicin and fusidic acid had antimicrobial activity against 87% of the bacterial strains. In the prosthesis-related gap model, there was a clear trend toward less bacterial survival for gentamicin-loaded bone cement after adding clindamycin or fusidic acid. Addition of clindamycin or fusidic acid into gentamicin-loaded bone cement yields an additional antimicrobial effect. The combination gentamicin and fusidic acid was effective against a higher number of clinical isolates than the combination of gentamicin with clindamycin, including gentamicin-resistant strains.