Sajeesh S, Sharma Chandra P
Division of Biosurface Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala, India.
J Biomed Mater Res B Appl Biomater. 2006 Feb;76(2):298-305. doi: 10.1002/jbm.b.30372.
In present study, novel pH sensitive polymethacrylic acid-chitosan-polyethylene glycol (PCP) nanoparticles were prepared under mild aqueous conditions via polyelectrolyte complexation. Free radical polymerization of methacrylic acid (MAA) was carried out in presence of chitosan (CS) and polyethylene glycol (PEG) using a water-soluble initiator and particles were obtained spontaneously during polymerization without using organic solvents or surfactants/steric stabilizers. Dried particles were analyzed by scanning electron microscopy (SEM) and particles dispersed in phosphate buffer (pH 7.0) were visualized under transmission electron microscope (TEM). SEM studies indicated that PCP particles have an aggregated and irregular morphology, however, TEM revealed that these aggregated particles were composed of smaller fragments with size less than 1 micron. Insulin and bovine serum albumin (BSA) as model proteins were incorporated into the nanoparticles by diffusion filling method and their in vitro release characteristics were evaluated at pH 1.2 and 7.4. PCP nanoparticles exhibited good protein encapsulation efficiency and pH responsive release profile was observed under in vitro conditions. Trypsin inhibitory effect of these PCP nanoparticles was studied using casein substrate and these particles displayed lesser inhibitory effect than reference polymer carbopol. Preliminary investigation suggests that these particles can serve as good candidate for oral peptide delivery.
在本研究中，通过聚电解质络合在温和的水性条件下制备了新型pH敏感的聚甲基丙烯酸 - 壳聚糖 - 聚乙二醇（PCP）纳米颗粒。在壳聚糖（CS）和聚乙二醇（PEG）存在下，使用水溶性引发剂进行甲基丙烯酸（MAA）的自由基聚合，并且在聚合过程中自发获得颗粒，无需使用有机溶剂或表面活性剂/空间稳定剂。通过扫描电子显微镜（SEM）分析干燥的颗粒，并在透射电子显微镜（TEM）下观察分散在磷酸盐缓冲液（pH 7.0）中的颗粒。SEM研究表明，PCP颗粒具有聚集且不规则的形态，然而，TEM显示这些聚集颗粒由尺寸小于1微米的较小碎片组成。通过扩散填充法将胰岛素和牛血清白蛋白（BSA）作为模型蛋白掺入纳米颗粒中，并在pH 1.2和7.4下评估其体外释放特性。PCP纳米颗粒表现出良好的蛋白质包封效率，并且在体外条件下观察到pH响应释放曲线。使用酪蛋白底物研究了这些PCP纳米颗粒的胰蛋白酶抑制作用，并且这些颗粒显示出比参比聚合物卡波姆更小的抑制作用。初步研究表明，这些颗粒可作为口服肽递送的良好候选物。
