Mawad Damia, Odell Ross, Poole-Warren Laura A
Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
Int J Pharm. 2009 Jan 21;366(1-2):31-7. doi: 10.1016/j.ijpharm.2008.08.038. Epub 2008 Sep 3.
Injectable hydrogels have potential biomedical applications ranging from tissue fillers to drug delivery vehicles. This study focussed on evaluating the structure of poly(vinyl alcohol) (PVA) hydrogels of variable solid content and high molecular weight model drug release from the networks formed via either conventional photo-polymerization compared with chemical initiation of polymerization using an oxidation-reduction (redox) reaction. Swelling behaviour was characterised in water to assess the structural properties. Model drugs, FITC-Dextran, 20 kDa (FD20) and 4 kDa (FD4) were loaded in the hydrogels prior to curing and drug release studies conducted. Redox-cured hydrogels were more swollen than UV-cured systems, lost approximately 20% of their polymer mass compared to only 5% from UV-cured hydrogels and subsequently exhibited networks of larger mesh sizes. Also, networks of variable solid contents showed different structural properties with systems of higher polymer concentration exhibiting a smaller mesh size. The difference in structural properties of the networks affected release of FD20, being faster in redox-cured than UV-cured hydrogels, and slower from systems of higher solid content. Release of FD4 was faster than FD20 from networks of same solid content. This study suggested that PVA hydrogels can be cured by redox-initiation to function as a controlled delivery system for macromolecular drugs.
可注射水凝胶具有从组织填充剂到药物递送载体等潜在的生物医学应用。本研究着重评估不同固含量的聚乙烯醇（PVA）水凝胶的结构，以及通过传统光聚合形成的网络中高分子量模型药物的释放情况，并与使用氧化还原（redox）反应进行化学引发聚合的情况进行比较。在水中对溶胀行为进行表征以评估结构特性。在固化和进行药物释放研究之前，将模型药物异硫氰酸荧光素标记的葡聚糖，20 kDa（FD20）和4 kDa（FD4）加载到水凝胶中。氧化还原固化的水凝胶比紫外线固化的系统溶胀得更厉害，其聚合物质量损失约20%，而紫外线固化的水凝胶仅损失5%，随后呈现出更大网孔尺寸的网络。此外，不同固含量的网络显示出不同的结构特性，聚合物浓度较高的系统呈现出较小的网孔尺寸。网络结构特性的差异影响了FD20的释放，在氧化还原固化的水凝胶中比在紫外线固化的水凝胶中释放得更快，并且在固含量较高的系统中释放得更慢。在相同固含量的网络中，FD4的释放比FD20更快。本研究表明，PVA水凝胶可以通过氧化还原引发进行固化，以作为大分子药物的控释系统发挥作用。
