美罗培南骨水泥体外生物力学及洗脱特性研究

目的 研究不同含量的美罗培南骨水泥的体外生物力学特性和药物洗脱特性.方法 40 g骨水泥(Palacos LV,40 g聚合物粉剂+20 ml单体液剂)中分别加入2、4、6 g注射用美罗培南和2、4 g注射用盐酸万古霉素复合,制备成A2、A4、A6、B2、B4和不含抗菌药物的对照组共6组样品.对6组样品分别进行能承受的...     

In vitro study of elution kinetics and bio-activity of meropenem-loaded acrylic bone cement

Background

Use of antibiotic-loaded acrylic bone cement to treat orthopaedic infections continues to remain popular, but resistance to routinely used antibiotics has led to the search for alternative, more effective antibiotics. We studied, in vitro, the elution kinetics and bio-activity of different concentrations of meropenem-loaded acrylic bone cement.

Methods

Meropenem-loaded bone cement cylinders of different concentrations were serially immersed in normal saline. Elution kinetics was studied by measuring the drug concentration in the eluate, collected at pre-determined intervals, by high-performance liquid chromatography. Bio-activity of the eluate of two different antibiotic concentrations was tested for a period of 3 weeks against each of the following organisms: Staphylococcus aureus ATCC 2593 (MSSA), Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, S. aureus ATCC 43300 (MRSA) and Klebsiella pneumoniae ATCC 700603 (ESBL).

Results

Meropenem elutes from acrylic bone cement for a period of 3–27 days depending on the concentration of antibiotic. Higher doses of antibiotic concentration resulted in greater elution of the antibiotic. The eluate was found to be biologically active against S. aureus ATCC 2593 (MSSA), P. aeruginosa ATCC 27853, E. coli ATCC 25922 and K. pneumoniae ATCC 700603 (ESBL) for a period of 3 weeks.

Conclusions

The elution of meropenem is in keeping with typical antibiotic-loaded acrylic bone cement elution characteristics. The use of high-dose meropenem-loaded acrylic bone cement seems to be an attractive option for treatment of resistant Gram-negative orthopaedic infections but needs to be tested in vivo.     

Biological and biomechanical effects of vancomycin and meropenem in acrylic bone cement

Antibiotic-loaded bone cement is extensively used in joint arthroplasty, but increasing bacteria resistance against common antibiotics has lead to a demand for alternative drugs. However, bone cement containing new additives must be characterized both biologically and mechanically. This study evaluated elution kinetics, antibacterial activity, and mechanical properties for cement loaded with vancomycin and/or meropenem. The presence of meropenem broadened the antibacterial spectrum and enhanced the elution of vancomycin. The mechanical properties were negatively affected by 1.0 g of vancomycin, but these detrimental effects were acceptable when only 0.5 g of vancomycin were added to a cement containing 0.5 g of meropenem. Further investigations on this formulation with adjusted antibiotic amounts are, however, necessary to reach the optimal compromise between the antibacterial and the mechanical properties of the bone cement.     

Vancomycin vs tobramycin elution from polymethylmethacrylate: an in vitro study

We fabricated batches of cement containing 0.5 gm, 1.0 gm, and 2.0 gm vancomycin and one with 1.0 gm tobramycin and shaped them into cylinders. They were immersed into 0.5 L of normal saline and the fluid volume was changed daily. Samples of fluid were obtained on days 1, 2, 3, 5, 7, 14, and 28. All fluid samples had antibiotic assays performed to quantitate the amount of elution for vancomycin or tobramycin. Vancomycin elution from PMMA occurred under our study conditions in similar quantities to that measured for tobramycin controls. Vancomycin-loaded PMMA cement may have a clinical role in the treatment of musculoskeletal sepsis caused by gram-positive bacteria, particularly if organisms resistant to the usual antibiotic agents are identified.     

The use of vancomycin and tobramycin in acrylic bone cement: biomechanical effects and elution kinetics for use in joint arthroplasty

We examined the effects of vancomycin on the compressive strength and fatigue life of bone cement and the pharmacokinetics and antimicrobial activity against methicillin-resistant Staphylococcus aureus of vancomycin eluted from bone cement, both alone and in combination with tobramycin. Two cements, Palacos and Simplex, were tested. Three antibiotic preparations were tested: lyophilized vancomycin (vancomycin-L), vancomycin powder (vancomycin-P), and tobramycin powder (Lilly, Indianapolis, IN). Although antibiotics did not significantly affect compressive strength, the fatigue life of bone cement was significantly decreased with vancomycin. Thus, fatigue testing revealed effects on cement strength not apparent by compression testing. Vancomycin-P had a substantially less detrimental effect on fatigue strength than vancomycin-L. Vancomycin-P elutes less efficiently than tobramycin. Although relatively little vancomycin-P eluted from bone cement, it retained biologic activity.     

低频超声对万古霉素骨水泥药物释放的影响

目的在体外和动物体内条件下研究低频超声对抗生素骨水泥（antibiotic-loaded bone cement,ALBC）的促释放作用及其规律.方法制作载万古霉素ALBC的体外试件和体内试件.分别将质量分数为5%和10%的ALBC体外试件随机分为对照组、100mW/cm^2超声组和300mW/cm^2超声组.所有试件于40 ml PBS中浸泡8 h后,超声组接受超声干预30 min,观察浸泡24 h内药物累积浓度的变化.另取健康新西兰大白兔16只,将质量分数为7.5%的ALBC植入髋关节后随机分为对照组和超声组,每组8只.超声组于术后不同时间接受超声干预30min（300mW/cm^2）,术后5 d内定时检测引流液和尿液中万古霉素浓度,术后4周检测ALBC残余药量.结果体外条件下100mW/cm^2超声组和1000 mW/cm^2超声组在浸泡24 h后的药物释放分别较10%对照组增加71.77%、73.62%,50mW/cm^2超声组和500 mW/cm^2超声组分别较5%对照组增加13.03%、23.78%.超声强度和药物载荷均显著增加ALBC的药物释放.体内条件下超声组药物释放量在术后1 d和5 d分别较对照组高148.18%（t=3.510,P＜0.01）和82.39%（t=2.345,P＜0.05）,术后4周超声组ALBC药物溶出低于对照组（t=3.697,P＜0.01）.结论低频连续型超声能促进和加快ALBC的药物释放.     

Mechanical effects of the use of vancomycin and meropenem in acrylic bone cement

Background The increasing resistance of certain bacteria to antibiotics commonly used in bone cements has led to a demand for alternative antibacterial agents. The antibiotics added to bone cements may, however, have detrimental effects on the mechanical properties of the cement.

Material and methods We evaluated the mechanical effects of adding vancomycin and meropenem to bone cement by compression, bending and fatigue tests.

Results Addition of vancomycin at a concentration of up to 2.5% (w/w) had no effect on the compressive strength. Bending and fatigue strength were negatively affected by vancomycin but not by meropenem.

Interpretation A cement containing 1.25% vancomycin and 1.25% meropenem might be an interesting compromise between the introduction of antibacterial properties and preservation of the mechanical properties. With this concentration of additives the compressive strength and the fatigue strength remain unchanged, while the bending strength (-14%) and the bending modulus (-9%) are only slightly reduced and remain above the limits set by the ISO5833 standard.     

Mechanical effects of the use of vancomycin and meropenem in acrylic bone cement

Background?The increasing resistance of certain bacteria to antibiotics commonly used in bone cements has led to a demand for alternative antibacterial agents. The antibiotics added to bone cements may, however, have detrimental effects on the mechanical properties of the cement.

Material and methods?We evaluated the mechanical effects of adding vancomycin and meropenem to bone cement by compression, bending and fatigue tests.

Results?Addition of vancomycin at a concentration of up to 2.5% (w/w) had no effect on the compressive strength. Bending and fatigue strength were negatively affected by vancomycin but not by meropenem.

Interpretation?A cement containing 1.25% vancomycin and 1.25% meropenem might be an interesting compromise between the introduction of antibacterial properties and preservation of the mechanical properties. With this concentration of additives the compressive strength and the fatigue strength remain unchanged, while the bending strength (–14%) and the bending modulus (–9%) are only slightly reduced and remain above the limits set by the ISO5833 standard.     

Effective bactericidal activity of tobramycin and vancomycin eluted from acrylic bone cement

We studied the bioactivity of vancomycin and tobramycin eluted from methylmethacrylate bone cement. Aliquots of the drainage were obtained at 1, 6, 12 and 24 hours following total hip prosthetic implantation with vancomycin-tobramycin-loaded cement in 3 patients. The samples were analyzed with fluorescence polarization immunoassay and bioassay, using group B streptococcus for vancomycin and Escherichia coli for tobramycin. These bacteria were selected due to the effectiveness of vancomycin and poor effectiveness of tobramycin against group B streptococcus and conversely with E. coli.

The immunodetection of vancomycin averaged 14 (1 hour), 9 (6 hours), 10 (12 hours) and 11 μg/mL (24 hours). The bioassay averaged 47, 36, 79 and 41 μg/mL (p = 0.03). The immunodetection of tobramycin averaged 43, 21, 18 and 14 μg/mL; and bioassay 30, 15, 15 and 12 μg/mL (p = 0.1). Both antibiotics eluted with a highly effective bactericidal activity. Our findings indicate that the presence of tobramycin has a synergistic-like effect on the bactericidal activity of vancomycin, which has not been previously reported. We recommend a combination of vancomycin and tobramycin with cement for the treatment of orthopedic infections caused by gram-positive organisms.     

Effective bactericidal activity of tobramycin and vancomycin eluted from acrylic bone cement

We studied the bioactivity of vancomycin and tobramycin eluted from methylmethacrylate bone cement. Aliquots of the drainage were obtained at 1, 6, 12 and 24 hours following total hip prosthetic implantation with vancomycin-tobramycin-loaded cement in 3 patients. The samples were analyzed with fluorescence polarization immunoassay and bioassay, using group B streptococcus for vancomycin and Escherichia coli for tobramycin. These bacteria were selected due to the effectiveness of vancomycin and poor effectiveness of tobramycin against group B streptococcus and conversely with E. coli. The immunodetection of vancomycin averaged 14 (1 hour), 9 (6 hours), 10 (12 hours) and 11 _6;g/mL (24 hours). The bioassay averaged 47, 36, 79 and 41 _6;g/mL (p = 0.03). The immunodetection of tobramycin averaged 43, 21, 18 and 14 _6;g/mL; and bioassay 30, 15, 15 and 12 _6;g/mL (p = 0.1). Both antibiotics eluted with a highly effective bactericidal activity. Our findings indicate that the presence of tobramycin has a synergistic-like effect on the bactericidal activity of vancomycin, which has not been previously reported. We recommend a combination of vancomycin and tobramycin with cement for the treatment of orthopedic infections caused by gram-positive organisms.     

Effective bactericidal activity of tobramycin and vancomycin eluted from acrylic bone cement

We studied the bioactivity of vancomycin and tobramycin eluted from methylmethacrylate bone cement. Aliquots of the drainage were obtained at 1, 6, 12 and 24 hours following total hip prosthetic implantation with vancomycin-tobramycin-loaded cement in 3 patients. The samples were analyzed with fluorescence polarization immunoassay and bioassay, using group B streptococcus for vancomycin and Escherichia coli for tobramycin. These bacteria were selected due to the effectiveness of vancomycin and poor effectiveness of tobramycin against group B streptococcus and conversely with E. coli. The immunodetection of vancomycin averaged 14 (1 hour), 9 (6 hours), 10 (12 hours) and 11 microg/mL (24 hours). The bioassay averaged 47, 36, 79 and 41 microg/mL (p = 0.03). The immunodetection of tobramycin averaged 43, 21, 18 and 14 microg/mL; and bioassay 30, 15, 15 and 12 microg/mL (p = 0.1). Both antibiotics eluted with a highly effective bactericidal activity. Our findings indicate that the presence of tobramycin has a synergistic-like effect on the bactericidal activity of vancomycin, which has not been previously reported. We recommend a combination of vancomycin and tobramycin with cement for the treatment of orthopedic infections caused by gram-positive organisms.     

低频脉冲型超声治疗起始时间对载万古霉素骨水泥药动及药效特性的影响

目的 研究低频脉冲型超声治疗的起始时间对载万古霉素骨水泥的药物释放动力（药动）特性与抗菌性能的影响及其机制。方法 在新西兰大白兔的髋关节植入载万古霉素骨水泥并接种标准菌株。超声A组于植入后0．5h治疗12h，超声B组于植入后12h治疗12h，对照组不予超声治疗。取超声A组及超声B组动物各2只，测定超声治疗时髋关节腔内渗血量。余动物于植入后定时测定髋关节引流液的药物浓度，计算药动及药效参数。植入后48h采集髋关节腔渗液及股骨近端髓腔组织，计数活菌量。结果超声B组有效抑菌浓度持续时间（T〉MIC）较对照组和超声A组分别延长20．51、21．81h。超声A组及B组的髋关节腔细菌密度分别较对照组下降lg^-1 1．62、lg^-1 2．77CFU／ml。超声B组股骨髓腔内细菌密度较对照组下降lg^-1 1．29CFU／g。超声B组髋关节渗血量显著低于超声A组。回归分析中，T〉MIC及低频脉冲型超声与载万古霉素骨水泥的协同抗菌效应差异有统计学意义。结论 与术后即刻超声治疗相比，组织渗血减轻时予以超声治疗能有效延长局部T〉MIC，提高载万古霉素骨水泥的抗菌性能。     

In vitro elution of vancomycin from calcium phosphate cement

Antibiotic-impregnated bone cement beads have become popular for the treatment of osteomyelitis and/or prosthesis infection. However, bone cement has the disadvantage of heating up during polymerization of cement. Recently, calcium phosphate cement (CPC) has been used as a bone replacement and augmentation, and it does not heat up during polymerization. First, we measured the release rate of vancomycin (VCM) from bone cement and CPC impregnated with VCM for 2 weeks in vitro. The mean concentration of VCM for CPC was 62.6 times at 7 days (258 ± 29 vs 4.12 ± 1.0) and 6.7 times at 13 days (15.5 ± 5.5 vs 2.3 ± 0.7). Second, we were successful in treating 2 cases of osteomyelitis and prosthesis infection with VCM-impregnated CPC. From this study, we concluded that VCM-impregnated CPC might be an effective material for the treatment of osteomyelitis and/or prosthesis infection.     

高功率密度低频超声间断辐照对载万古霉素骨水泥药物释放的促进作用

目的 探讨高功率密度低频超声辐照模式对超卢促进药物释放的影响.方法 制备质量分数10%的载万古霉索骨水泥(Vancomycin-loaded bone cement,VLBC)圆柱体试件.随机分为对照组、超声连续辐照组、超声间断辐照组,后两组接受超声辐照14 d.浸泡28 d内定时测定万古霉素浓度.计算有效抑菌浓度维持时间(T>MIC)、14～28 d哑抑菌浓度释药量、14d内累积释药量并行曲线拟合;浸泡14d后行扫描电镜观察.结果 超声间断辐照组(T>MIC)较对照组及超声连续辐照组分别提高6.56 d、7.09 d,超声连续辐照组较对照组下降0.53 d.超声间断辐照组亚抑菌浓度释药量较对照组及超声连续辐照组分别下降0.16 mg、0.19 mg;14 d累积释约量较对照组及超声连续辐照组分别提高2.88 mg、2.81 mg.三组采用指数增长至最大值模型拟合效果均理想.超声间断辐照组Mo、MmaxMo、K均较对照组及超声连续辐照组提高,超声连续辐照组Mo较对照组提高,但Mo、MmaxMo、K较对照组降低.结论 高功率密度低频超声间断辐照对VLBC的表面释放和内部弥散有明显的促进作用,连续辐照抑制VLBC的内部弥散.     

Antibiotic elution from acrylic bone cement loaded with high doses of tobramycin and vancomycin

Two‐stage revision treatment of prosthetic joint infection (PJI) frequently employs the use of a temporary bone cement spacer loaded with multiple antibiotic types. Tobramycin and vancomycin are commonly used antibiotics in cement spacers, however, there is no consensus on the relative concentrations and combinations that should be used. Therefore, the purpose of this study was to investigate the influence of dual antibiotic loading on the total antibiotic elution and compressive mechanical properties of acrylic bone cement. Varying concentrations of tobramycin (0–3 g) and vancomycin (0–3 g) were added either alone or in combination to acrylic cement (Palacos R), resulting in 12 experimental groups. Samples were submerged in 37°C saline for 28 d and sampled at specific time points. The collected eluent was analyzed to determine the cumulative antibiotic release. In addition, the cement's compressive mechanical properties and porosity were characterized. Interestingly, the cement with the highest concentration of antibiotics did not possess the best elution properties. Cement samples containing both 3 g of tobramycin and 2 g vancomycin demonstrated the highest cumulative antibiotic release after 28 d, which was coupled with a significant decrease in the mechanical properties and an increased porosity. The collected data also suggests that tobramycin elutes more effectively than vancomycin from cement. In conclusion, this study demonstrates that high antibiotic loading in cement does not necessarily lead to enhanced antibiotic elution. Clinically this information may be used to optimize cement spacer antibiotic loading so that both duration and amount of antibiotics eluted are optimized. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1078–1085, 2018.

     

阶段注射法预防椎体成型术中骨水泥渗漏的实验研究

目的通过离体实验评价两阶段注射法在椎体成型术中对骨水泥渗漏的预防作用。方法50个新鲜绵羊腰椎随机分成实验组及对照组。分别采用两阶段注射法及常规椎体成型方法,在X线透视引导下向椎体内注射总量为3mL的PMMA,模拟临床椎体成型术。实验组首先向椎体后部注射0.5mL的PMMA,待其固化后,再次向椎体内注射2.5mL的PMMA。对照组以常规方法向椎体内注射3mL的PMMA。通过X线及肉眼直视,统计两组骨水泥渗漏的发生率。结果对照组有8例出现骨水泥向椎管内渗漏,而实验组中仅2例,显著低于对照组(P=0.032)。尽管实验组骨水泥总体渗漏发生率56%高于对照组44%,但无统计学差别。结论两阶段注射法可显著降低骨水泥向椎管内方向渗漏的发生率。     

The in vitro elution characteristics of vancomycin combined with imipenem-cilastatin in acrylic bone-cements: a pharmacokinetic study

The aim of this in vitro study was to compare the elution characteristics of vancomycin alone and in combination with imipenem-cilastatin from 3 acrylic bone-cements (CMW1 [DePuy International, Blackpool, UK], Palacos R [Schering-Plough, Wehrheim, Germany], and Simplex P [Howmedica International, London, UK]). Six groups of 3 antibiotic-loaded cement disks were prepared, incorporating 2 g of vancomycin (3 groups) and 2 g of vancomycin plus 2 g of imipenem-cilastatin (3 groups). The disks were placed in saline baths for 5 weeks, with the baths being sampled periodically and the elution rates calculated. The total amount of vancomycin released by the cements treated with vancomycin alone was 7.98 mg for CMW1, 7.74 mg for Palacos R, and 6.76 mg for Simplex P; with the addition of imipenem-cilastatin, the total amount of vancomycin released by the 3 cements increased by 30.58%, 50.52%, and 50.15%. CMW1 had better elution characteristics than the other cements when treated with vancomycin alone; the elution of Palacos R and Simplex P was better than that of CMW1 when vancomycin was combined with imipenem-cilastatin.     

Elution and Biomechanical Properties of Meropenem‐Loaded Bone Cement

ObjectiveTo investigate the biomechanical and elution properties of meropenem‐loaded bone cement.MethodsBone cement (Palacos LV) with 5% (2 g/4 0g), 10% (4 g/40 g), and 15% (6 g/40 g) meropenem; 5% (2 g/40 g) and 10% (4 g/40 g) vancomycin; and blank bone cement were prepared in a total of six groups named A2, A4, A6, B2, B4, and A0 (antibiotic‐free). 36 cylinder specimens (6‐mm diameter and 12‐mm height) of all six groups were molded for a compression test. After the compression test, because of mechanical properties below the ISO standard requirements, groups B2, B4 were not subjected to a bending test. So a total of 24 rectangular strip specimens (10‐mm width, 75‐mm length, and 3.3‐mm thickness) for groups A2, A4, A6 and A0 were molded for the bending test. Between‐group differences of compressive strength, bending strength and bending modulus were analyzed. The meropenem standard was prepared as a series of standard solutions to calculate the standard curve. At a constant temperature of 37 °C, separately, meropenem‐loaded bone cement cylinder specimens (12 mm in diameter and 17 mm in length) of A2, A4 and A6 were serially immersed in saline solution without stirring. The eluent drug concentration at 24, 48, 72 h and 6, 12, 24 days was measured and the drug concentration‐time curve of meropenem was constructed.ResultsWith the exception of groups B2 and B4, all cements compressive strength values were well above the minimum requirement of the ISO 5833 standard (70 MPa). The compressive strength and bending strength values of group A4 were higher than those of group A0 (P < 0.05), but no difference was found between the A0, A2 and A6 groups (P > 0.05). There were no intergroup differences of bending modulus between the A0, A2, A4 and A6 groups (P > 0.05). A standard curve of meropenem was obtained and a regression equation was constructed: Y = 15.0265 X + 13.5218, r = 1.00. At 37 °C, the release of meropenem was rapid during the first 48 h for all A2, A4, A6 samples, and subsequent release continued to decrease.ConclusionWhen adding up to 15% (6 g/40 g) meropenem to the bone cement, the biomechanical properties were not reduced, and bone cement with 10% (4 g/40 g) meropenem had the best performance. At a constant temperature of 37°C, meropenem can be released from bone cement for up to 24 days.     

The effect of glycine filler on the elution rate of gentamicin from acrylic bone cement: a pilot study

Elution of antibiotics from acrylic bone cement (polymethylmethacrylate [PMMA]) is dependent on the access of fluid to the depths of the cement that contains the antibiotic. Commercially prepared antibiotic beads that are porous have higher elution rates than hand-mixed, nonporous antibiotic PMMA mixtures. To increase the elution of gentamicin from hand-mixed PMMA, glycine was added as a filler to produce porosity. Elution of gentamicin from the antibiotic PMMA-glycine mixture increased with increasing amounts of glycine. With 3.6 g gentamicin powder and 14 g of crystalline glycine per batch of Palacos PMMA, the elution of gentamicin from the PMMA at 2 days was, similar to the previously documented elution of gentamicin from commercially prepared porous Septopal PMMA beads. With further investigation it may be possible to identify a specific filler and a volume of filler that can be hand mixed in antibiotic PMMA to produce the elution behavior that is needed for specific clinical requirements.