Visual evidence of acidic environment within degrading poly(lactic-co-glycolic acid) (PLGA) microspheres
Visual evidence of acidic environment within degrading poly(lactic-co-glycolic acid) (PLGA) microspheres
复制标题
DOI：
10.1023/a:1007582911958
复制
发表时间：
2000-01-01
影响因子：
3.7
通讯作者：
Langer, R
中科院分区：
文献类型：
--
作者：
Fu, K;Pack, DW;Langer, R
目的.在过去的十年里。生物可降解聚合物已成为多种生物材料应用的选择材料。特别是，聚（乳酸-共-乙醇酸）（PLGA）微球已被广泛研究用于控制释放药物递送。然而，聚合物的降解产生酸性单体，并且内部聚合物环境的酸化是开发这些用于药物递送的装置的中心问题。为了定量测定聚合物内的酸度，我们将pH敏感的荧光染料（与10，000 Da葡聚糖缀合）包埋在微球内，并用共聚焦荧光显微镜对其进行成像。该技术允许可视化降解微球内pH的空间和时间分布（1）。我们的实验表明，形成一个非常酸性的环境中的颗粒与最低pH值低至1.5。结论。图像显示了pH梯度，其中最酸性的环境位于球体中心，边缘附近的pH值较高，这是酸性降解产物扩散控制释放的特征。
Purpose. In the past decade. biodegradable polymers have become the materials of choice for a variety of biomaterials applications. In particular, poly(lactic-co-glycolic acid) (PLGA) microspheres have been extensively studied for controlled-release drug delivery. However, degradation of the polymer generates acidic monomers, and acidification of the inner polymer environment is a central issue in the development of these devices for drug delivery.Methods. To quantitatively determine the intrapolymer acidity, we entrapped pH-sensitive fluorescent dyes (conjugated to 10,000 Da dextrans) within the microspheres and imaged them with confocal fluorescence microscopy. The technique allows visualization of the spatial and temporal distribution of pH within the degrading microspheres (1).Results. Our experiments show the formation of a very acidic environment within the particles with the minimum pH as low as 1.5.Conclusions. The images show a pH gradient, with the most acidic environment at the center of the spheres and higher pH near the edges, which is characteristic of diffusion-controlled release of the acidic degradation products.