Institute for Biodiagnostics (Atlantic), Neuroimaging Research Laboratory, National Research Council of Canada, Halifax, Nova Scotia, Canada.
Acta Biomater. 2012 Oct;8(10):3821-31. doi: 10.1016/j.actbio.2012.05.026. Epub 2012 May 30.
Degradable, bioceramic bone implants made of calcium polyphosphate (CPP) hold potential for controlled release of therapeutic agents in the treatment of localized bone disease. Magnetic resonance imaging techniques for non-invasively mapping fluid distribution, T(1) and T(2) relaxation times and the apparent diffusion coefficient were performed in conjunction with a drug elution protocol to resolve free and bound water components within the material microstructure in two CPP formulations (G1 and G2). The T(2) maps provided the most accurate estimates of free and bound water, and showed that G1 disks contained a detectable free water component at all times, with drug release dominated by a Fickian diffusion mechanism. Drug release from G2 disks was characterized by a combined diffusional/structural relaxation mechanism, which may be related to the gradual infiltration of a free water component associated with swelling and/or chemical degradation.
可降解的生物陶瓷钙多磷酸盐（CPP）骨植入物具有在局部骨病治疗中控制治疗剂释放的潜力。通过与药物洗脱方案相结合，使用磁共振成像技术对流体分布、T(1)和 T(2)弛豫时间以及表观扩散系数进行非侵入性测绘，以解析两种 CPP 配方（G1 和 G2）材料微结构内的游离水和结合水成分。T(2)图谱提供了游离水和结合水的最准确估计，并且表明 G1 盘始终含有可检测的游离水成分，药物释放主要由菲克扩散机制控制。G2 盘的药物释放特征是扩散/结构弛豫机制的结合，这可能与与肿胀和/或化学降解相关的游离水成分的逐渐渗透有关。
