Pharmaceutical Technology, School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
Eur J Pharm Sci. 2012 Aug 30;47(1):170-8. doi: 10.1016/j.ejps.2012.05.013. Epub 2012 Jun 6.
Surface-eroding biodegradable polymers can provide many advantages in drug delivery, such as controllable and zero-order drug release. Photocrosslinkable poly(ester anhydride)s are a recently developed family of surface-eroding polymers with readily modifiable oligomer chemistry allowing tailoring of polymer properties. For example, in vivo release rate of peptide from photocrosslinked poly(ester anhydride)s can be controlled by oligomer hydrophobicity. In this study, X-ray microtomography (micro-CT) was used to gain a deeper understanding on internal structure, polymer erosion and drug release mechanisms of photocrosslinked poly(ester anhydride)s. Micro-CT is non-destructive and able to provide quantitative and qualitative information on the 3D structure of the sample in micrometer resolution. Photocrosslinked poly(ester anhydride) samples with varying drug loading degrees (propranolol HCl 0%, 10% and 60% w/w) and hydrophobicity (with and without 12-carbon alkenyl chain) were prepared. The samples, both freshly prepared and exposed to buffer solution for varying durations were characterized by micro-CT. The results showed that drug release from photocrosslinked poly(ester anhydride)s was primarily controlled by the surface erosion. However, drug diffusion had also a significant role in drug release from less hydrophobic samples with very high (60% w/w) drug loading degrees. In conclusion, micro-CT is a valuable tool in the characterization of surface-eroding polymers.
表面侵蚀型可生物降解聚合物在药物传递中具有许多优势，例如可控制的零级药物释放。光交联聚酯酐是最近开发的一类表面侵蚀聚合物，具有易于修饰的低聚物化学性质，可定制聚合物性能。例如，光交联聚酯酐中肽的体内释放速率可以通过低聚物疏水性来控制。在这项研究中，使用 X 射线微断层扫描（micro-CT）技术深入了解光交联聚酯酐的内部结构、聚合物侵蚀和药物释放机制。micro-CT 是一种非破坏性技术，能够以微米分辨率提供样品三维结构的定量和定性信息。制备了不同载药程度（盐酸普萘洛尔 0%、10%和 60%w/w）和疏水性（有和没有 12 碳烯基链）的光交联聚酯酐样品。通过 micro-CT 对新鲜制备的和暴露于缓冲溶液不同时间的样品进行了表征。结果表明，光交联聚酯酐的药物释放主要受表面侵蚀控制。然而，对于疏水性较低且载药程度非常高（60%w/w）的样品，药物扩散在药物释放中也起着重要作用。总之，micro-CT 是研究表面侵蚀聚合物的一种有价值的工具。
