Sandal Nidhi, Mittal Gaurav, Bhatnagar Aseem, Pathak Dharam Pal, Singh Ajay Kumar
Department of Nuclear Medicine, Institute of Nuclear Medicine and Allied Sciences, Defence R&D Organisation, Brig. SK Mazumdar Road, Delhi 110 054, India.
Division of Pharmaceutical Chemistry, DIPSAR, MB Road, Pushp Vihar, New Delhi 110 017, India.
J Drug Deliv. 2017;2017:4875784. doi: 10.1155/2017/4875784. Epub 2017 Nov 29.
Prussian blue (PB, ferric hexacyanoferrate) is approved by US-FDA for internal decorporation of Cesium-137 (Cs) and Thallium-201 (Tl).
Since PB is a costly drug, pH-dependent oral delivery system of PB was developed using calcium alginate matrix system.
Alginate (Alg) beads containing PB were optimized by gelation of sodium alginate with calcium ions and effect of varying polymer concentration on encapsulation efficiency and release profile was investigated. Scanning electron microscopy (SEM) was carried out to study surface morphology. Adsorption efficacy of Alg-PB beads for Tl was evaluated and compared with native PB. pH-dependent release of the formulation was studied in humans using gamma scintigraphy.
Encapsulation efficiencies of Alg-PB beads with 0.5, 1.0, 1.5, and 2.0% polymer solution were 99.9, 91, 92, and 93%, respectively. SEM and particle size analysis revealed differences between formulations in their appearance and size distribution. No drug release was seen in acidic media (pH of 1-2) while complete release was observed at pH of 6.8. Dissolution data was fitted to various mathematical models and beads were found to follow Hixson-Crowell mechanism of release. The pH-dependent release of beads was confirmed by pharmacoscintigraphy in humans.
普鲁士蓝（PB，六氰合铁酸铁）已获美国食品药品监督管理局批准用于体内去除铯 - 137（Cs）和铊 - 201（Tl）。
由于PB是一种昂贵的药物，因此使用海藻酸钙基质系统开发了PB的pH依赖性口服给药系统。
通过海藻酸钠与钙离子凝胶化优化含PB的海藻酸盐（Alg）珠，并研究不同聚合物浓度对包封效率和释放曲线的影响。进行扫描电子显微镜（SEM）以研究表面形态。评估Alg - PB珠对Tl的吸附效果并与天然PB进行比较。使用γ闪烁显像术在人体中研究该制剂的pH依赖性释放。
聚合物溶液浓度为0.5%、1.0%、1.5%和2.0%的Alg - PB珠的包封效率分别为99.9%、91%、92%和93%。SEM和粒度分析揭示了制剂在外观和尺寸分布上的差异。在酸性介质（pH为1 - 2）中未见药物释放，而在pH为6.8时观察到完全释放。将溶解数据拟合到各种数学模型，发现珠遵循希克森 - 克劳威尔释放机制。通过人体药物闪烁显像术证实了珠的pH依赖性释放。
