Tuning drug uptake and release rates through different morphologies and pore diameters of confined mesoporous silica
Tuning drug uptake and release rates through different morphologies and pore diameters of confined mesoporous silica
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DOI：
10.1016/j.micromeso.2008.09.022
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发表时间：
2009-02-01
影响因子：
5.2
通讯作者：
Bein, Thomas
中科院分区：
文献类型：
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作者：
Cauda, Valentina;Muehlstein, Lea;Bein, Thomas
在阳极氧化铝膜(AAM)的孔道内(直径120-200 nm，长60微米)合成了三种有序介孔二氧化硅体系(OMS)，即孔径约为4和6 nm的中孔排列成柱状排列的体系(I)和以6 nm为孔呈圆形排列的体系(III)。这些模型体系允许人们通过使用没有明显外表面的体系来消除OMS的颗粒大小和颗粒形态的影响。布洛芬是一种抗炎药物，通过从溶液中扩散的方式被加入到这些OMS-AAM体系中。吸收结果表明，与AAM相比，包合的OMS提高了药物的吸附容量。在孔径较大的柱状OMS-AAM体系中，吸附能力最强。环状体系对布洛芬的吸附能力最低，其结构参数与柱状体系相似，即孔径、孔体积和氮气比表面积。布洛芬分子通过缺陷的低可及性为布洛芬分子带来了显著的扩散阻力，从而表明孔形态对分子扩散有很大影响。在模拟体液(SBF)中研究了几分钟到几周的时间窗内药物的释放。对于柱状样品，药物释放速率随孔径的减小而降低。从圆形样品中布洛芬以快速动力学释放：推测药物没有深入到结构中。近30%的总吸附量被保留在圆形样品中。此外，大约一天后，在介孔主体的表面检测到羟基磷灰石前驱体的沉淀，表明OMS-AAM体系表现出生物活性。这意味着，在延长释放时间后，药物向系统外的扩散可以通过部分堵塞毛孔来减缓。(C)2008 Elsevier Inc.保留所有权利。
Three ordered mesoporous silica systems (OMS) were synthesized within the channels (120-200 nm in diameter, 60 mu m long) of anodic alumina membranes (AAMs), i.e., systems (i) and (ii) with pore diameters of about 4 and 6 nm having a columnar alignment of mesopores and system (iii) featuring 6 nm pores arranged in a circular structure. These model systems allow one to eliminate the effect of particle size and particle morphology of the OMS, by using systems without significant external surface.Ibuprofen, an anti-inflammatory drug, was incorporated into these OMS-AAM systems by diffusion from solution. Uptake results showed that the included OMS increases the drug adsorption capacity with respect to the AAM as such. The highest uptake values were reached in the columnar OMS-AAM system with the larger pore diameter. The circular system, having similar structural parameters as the columnar one, i.e. pore size, pore volume and nitrogen surface area, showed the lowest adsorption capacity toward ibuprofen. The low accessibility of circular mesopores through defects creates a significant diffusion resistance for the ibuprofen molecules, thus showing that pore morphology strongly influences molecular diffusion.Drug release in a time window ranging from minutes to weeks was studied in a simulated body fluid (SBF). Concerning the columnar samples, the drug release rate decreased upon reducing the pore diameter. From the circular sample the ibuprofen was released with fast kinetics: it is proposed that the drug did not deeply diffuse into the structure. Nearly 30% of the total amount adsorbed was retained in the circular sample. Furthermore, after about a day the precipitation of hydroxyapatite precursors was detected on the surface of the mesoporous host, showing that the OMS-AAM system exhibits a "bioactive" behavior. This implies that after prolonged release times the diffusion of the drug out of the system can be slowed down through partial pore blocking. (C) 2008 Elsevier Inc. All rights reserved.