Andreani Tatiana, Miziara Leonardo, Lorenzón Esteban N, de Souza Ana Luiza R, Kiill Charlene P, Fangueiro Joana F, Garcia Maria L, Gremião Palmira D, Silva Amélia M, Souto Eliana B
Department of Biology and Environment, University of Tras-os Montes e Alto Douro, UTAD, Quinta de Prados, P-5001-801 Vila Real, Portugal; Centre for Research and Technology of Agro-Environmental and Biological Sciences, CITAB, UTAD, Quinta de Prados, P-5001-801 Vila Real, Portugal.
Department of Pharmaceutical Sciences, UNESP-Universidade Estadual Paulista, Rodovia Araraquara-Jau, Km. 01, Araraquara, São Paulo, Brazil.
Eur J Pharm Biopharm. 2015 Jun;93:118-26. doi: 10.1016/j.ejpb.2015.03.027. Epub 2015 Apr 3.
The present paper focuses on the development and characterization of silica nanoparticles (SiNP) coated with hydrophilic polymers as mucoadhesive carriers for oral administration of insulin. SiNP were prepared by sol-gel technology under mild conditions and coated with different hydrophilic polymers, namely, chitosan, sodium alginate or poly(ethylene glycol) (PEG) with low and high molecular weight (PEG 6000 and PEG 20000) to increase the residence time at intestinal mucosa. The mean size and size distribution, association efficiency, insulin structure and insulin thermal denaturation have been determined. The mean nanoparticle diameter ranged from 289 nm to 625 nm with a PI between 0.251 and 0.580. The insulin association efficiency in SiNP was recorded above 70%. After coating, the association efficiency of insulin increased up to 90%, showing the high affinity of the protein to the hydrophilic polymer chains. Circular dichroism (CD) indicated that no conformation changes of insulin structure occurred after loading the peptide into SiNP. Nano-differential scanning calorimetry (nDSC) showed that SiNP shifted the insulin endothermic peak to higher temperatures. The influence of coating on the interaction of nanoparticles with dipalmitoylphosphatidylcholine (DPPC) biomembrane models was also evaluated by nDSC. The increase of ΔH values suggested a strong association of non-coated SiNP and those PEGylated nanoparticles coated with DPPC polar heads by forming hydrogen bonds and/or by electrostatic interaction. The mucoadhesive properties of nanoparticles were examined by studying the interaction with mucin in aqueous solution. SiNP coated with alginate or chitosan showed high contact with mucin. On the other hand, non-coated SiNP and PEGylated SiNP showed lower interaction with mucin, indicating that these nanoparticles can interdiffuse across mucus network. The results of the present work provide valuable data in assessing the in vitro performance of insulin-loaded SiNP coated with mucoadhesive polymers.
本文重点研究了涂覆亲水性聚合物的二氧化硅纳米颗粒（SiNP）作为胰岛素口服给药的粘膜粘附载体的开发与特性。SiNP通过溶胶 - 凝胶技术在温和条件下制备，并涂覆不同的亲水性聚合物，即壳聚糖、海藻酸钠或低分子量和高分子量的聚乙二醇（PEG）（PEG 6000和PEG 20000），以增加在肠粘膜的停留时间。测定了平均尺寸和尺寸分布、结合效率、胰岛素结构和胰岛素热变性。纳米颗粒的平均直径范围为289nm至625nm，PI在0.251至0.580之间。SiNP中胰岛素的结合效率记录在70%以上。涂覆后，胰岛素的结合效率提高到90%，表明蛋白质与亲水性聚合物链具有高亲和力。圆二色性（CD）表明，将肽加载到SiNP中后，胰岛素结构没有发生构象变化。纳米差示扫描量热法（nDSC）表明，SiNP将胰岛素的吸热峰移至更高温度。还通过nDSC评估了涂层对纳米颗粒与二棕榈酰磷脂酰胆碱（DPPC）生物膜模型相互作用的影响。ΔH值的增加表明未涂覆的SiNP和那些通过形成氢键和/或通过静电相互作用涂覆有DPPC极性头的聚乙二醇化纳米颗粒之间有强烈的结合。通过研究纳米颗粒与水溶液中粘蛋白的相互作用来检查其粘膜粘附特性。涂覆有海藻酸盐或壳聚糖的SiNP与粘蛋白有高度接触。另一方面，未涂覆的SiNP和聚乙二醇化SiNP与粘蛋白的相互作用较低，表明这些纳米颗粒可以在粘液网络中相互扩散。本研究结果为评估负载胰岛素的涂覆粘膜粘附聚合物的SiNP的体外性能提供了有价值的数据。
