Cai Xun-Zi, Chen Xian-Zhen, Yan Shi-Gui, Ruan Zou-Rong, Yan Rui-Jian, Ji Kang, Xu Jia
Department of Orthopaedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
J Biomed Mater Res B Appl Biomater. 2009 Jul;90(1):11-7. doi: 10.1002/jbm.b.31288.
Ultrasound holds promise for enhancing the vancomycin release from cement though the length of time when local drug level exceeded the minimum inhibitory concentration (T(>MIC)) was not prolonged by the previous protocol of milliwatt-level ultrasonication. Here vancomycin-loaded cements were subjected to continuous watt-level ultrasonication (CUG), intermittent watt-level ultrasonication (IUG) or no ultrasonication (NUG) for 14 d during immersion in 40-ml phosphate buffered saline (PBS) for 28 d. The T(>MIC) for IUG was more than three times that for NUG. In contrast, T(>MIC) for CUG was slightly shortened. The subtherapeutic release of vancomycin between 15 d and 28 d for IUG was one-ninth that for NUG. The fitting equations indicated a significant enhancement on the burst release and the slow release for IUG; however, the continuous ultrasonication hampered the slow release. SEM images exhibited denser craters and pores with larger diameters and less residual drug in specimens from IUG relative to those from both CUG and NUG. Intermittent watt-level ultrasonication improved the ultrasound-enhanced vancomycin release from cement in view of the prolonged T(>MIC) and the inhibited subtherapeutic release compared with continuous ultrasonication. The mechanisms may be associated with the distinctive effects of detaching forces and pushing forces by acoustic microstreams.
超声有望增强万古霉素从骨水泥中的释放，尽管之前毫瓦级超声处理方案并未延长局部药物浓度超过最低抑菌浓度的时间（T(>MIC)）。在此，将载万古霉素的骨水泥在40毫升磷酸盐缓冲盐水（PBS）中浸泡28天的过程中，分别进行连续瓦级超声处理（CUG）、间歇瓦级超声处理（IUG）或不进行超声处理（NUG），持续14天。IUG的T(>MIC)是NUG的三倍多。相比之下，CUG的T(>MIC)略有缩短。IUG在15天至28天期间万古霉素的亚治疗性释放量是NUG的九分之一。拟合方程表明IUG在突释和缓释方面有显著增强；然而，连续超声处理阻碍了缓释。扫描电子显微镜图像显示，相对于CUG和NUG的标本，IUG标本中的凹坑和孔隙更密集，直径更大，残留药物更少。与连续超声处理相比，间歇瓦级超声处理通过延长T(>MIC)和抑制亚治疗性释放，改善了超声增强的万古霉素从骨水泥中的释放。其机制可能与声微流产生的分离力和推力的独特作用有关。
