Ensing Geert T, Hendriks Johannes G E, Jongsma Jelmer E, van Horn Jim R, van der Mei Henny C, Busscher Henk J
Department of Biomedical Engineering, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
J Biomed Mater Res B Appl Biomater. 2005 Oct;75(1):1-5. doi: 10.1002/jbm.b.30140.
Gentamicin-loaded acrylic beads are loosely placed in infected bone cavities, whereas gentamicin-loaded acrylic bone cement is used as a mechanical filler in bone to anchor prosthetic components. Both drug delivery systems are used to decrease infection rates by gentamicin release. The objective of this study is to investigate the effects of pulsed ultrasound on gentamicin release from both materials. Gentamicin release from gentamicin-loaded beads (Septopal) and from three commercially-available brands of gentamicin-loaded bone cement (CMW 1, Palacos R-G, and Palamed G) was measured after 18 h of exposure in PBS to an ultrasonic field of 46.5 kHz in a 1:3 duty cycle with an average acoustic intensity of 167 mW/cm(2). Samples not exposed to ultrasound were used as controls. Pulsed ultrasound significantly enhanced gentamicin release from gentamicin-loaded beads, whereas gentamicin release from the gentamicin-loaded bone cements was not significantly enhanced. Mercury intrusion porosimetry revealed an increased distribution of pores between 0.1 and 0.01 microm in beads after gentamicin release, while in bone cements no increase in the number of pores was found. Increased gentamicin release in beads due to ultrasound may be explained by micro-streaming in a porous structure, whereas the absence of changes in pore structure after gentamicin release in bone cement is concurrent with the lack of an enhanced release of the antibiotic by ultrasound. As an effective treatment of infections requires high local concentrations of antibiotic, increased gentamicin release due to ultrasound may be of clinical significance, especially since ultrasound has been demonstrated to increase bacterial killing by antibiotics.
载有庆大霉素的丙烯酸珠粒被松散地放置在感染的骨腔中，而载有庆大霉素的丙烯酸骨水泥则用作骨中的机械填充物以固定假体组件。两种药物递送系统都通过庆大霉素的释放来降低感染率。本研究的目的是研究脉冲超声对两种材料中庆大霉素释放的影响。将载有庆大霉素的珠粒（Septopal）以及三种市售品牌的载有庆大霉素的骨水泥（CMW 1、Palacos R-G和Palamed G）在PBS中于46.5 kHz的超声场中以1:3的占空比、平均声强为167 mW/cm²暴露18小时后，测量庆大霉素的释放量。未暴露于超声的样品用作对照。脉冲超声显著增强了载有庆大霉素珠粒中庆大霉素的释放，而载有庆大霉素的骨水泥中庆大霉素的释放没有显著增强。压汞法孔隙率测定显示，庆大霉素释放后珠粒中0.1至0.01微米之间的孔隙分布增加，而骨水泥中孔隙数量没有增加。超声导致珠粒中庆大霉素释放增加可能是由于多孔结构中的微流作用，而骨水泥中庆大霉素释放后孔隙结构没有变化，这与超声未增强抗生素释放的情况一致。由于有效的感染治疗需要高局部浓度的抗生素，超声导致庆大霉素释放增加可能具有临床意义，特别是因为超声已被证明可增强抗生素的杀菌作用。
