Department of Physical Chemistry, Institute of Chemistry, São Paulo State University (UNESP), Araraquara, SP, 14801-970, Brazil.
Department of Physical Chemistry, Institute of Chemistry, São Paulo State University (UNESP), Araraquara, SP, 14801-970, Brazil.
Colloids Surf B Biointerfaces. 2019 May 1;177:228-234. doi: 10.1016/j.colsurfb.2019.02.008. Epub 2019 Feb 6.
Hydrophobic drugs, such as methotrexate, are not easily delivered into the human body. Therefore, the use of amphiphilic nanoplatforms to the transport of these drugs through the bloodstream is a challenge. While the hydrophobic region interacts with the drug, the hydrophilic outer layer enhances its bioavailability and circulation time. Poly (ethylene glycol)-block-poly(ε-caprolactone) PEG-b-PCL micelles are biodegradable and biocompatible, allowing its use as a nanocarrier for drug delivery systems. The stealth property of PEG that composes the outer layer of nanoplatforms, makes the micelle unperceivable to phagocytic cells, increasing the circulation time in the human body. In addition, folic acid functionalization enables micelle selectively targeting to cancer cells, improving treatment efficiency and reducing side effects. In this work, PEG-b-PCL copolymer was synthesized by ring opening polymerization (ROP) of the ε-caprolactone with Poly(ethylene glycol) as a macroinitiator and tin(II) 2-ethyl hexanoate as a catalyst. Functionalization of such micelles with folic acid occurred through the modification of the PEG terminal group. The surface modification of the copolymer micelles resulted in higher critical micellar concentration (CMC), increasing approximately 100 times. The synthesis of the copolymers resulted in molecular weight around 3000 g mol with low polydispersity. The polymer micelles have a hydrodynamic diameter in the range of 100-200 nm and the functionalized sample doesn't show aggregation in the considered pH range. High incorporation efficiency was obtained with a minimum percentage of 85%. The drug release profile and linearization from the Peppas model confirmed the interaction of methotrexate with the hydrophobic segment of the copolymer and its release mechanism by relaxation and/or degradation of the chains, making PEG-b-PCL micelles suitable candidates for hydrophobic drug delivery systems.
疏水性药物,如甲氨蝶呤,不易进入人体。因此,利用两亲性纳米平台将这些药物通过血流输送是一个挑战。疏水性区域与药物相互作用,而亲水性外层则提高了其生物利用度和循环时间。聚乙二醇-嵌段-聚(ε-己内酯)PEG-b-PCL 胶束是可生物降解和生物相容的,允许其用作药物传递系统的纳米载体。组成纳米平台外层的聚乙二醇的隐身特性使得胶束不易被吞噬细胞察觉,从而增加了在人体中的循环时间。此外,叶酸功能化使胶束能够选择性地靶向癌细胞,提高治疗效率并减少副作用。在这项工作中,通过聚乙二醇开环聚合(ROP)将 ε-己内酯聚合,以聚乙二醇作为大分子引发剂和辛酸亚锡作为催化剂合成了 PEG-b-PCL 共聚物。通过修饰 PEG 端基实现了对胶束的叶酸功能化。共聚物胶束的表面改性导致临界胶束浓度(CMC)升高,约增加了 100 倍。共聚物的合成得到了分子量约为 3000g/mol 的低多分散性聚合物。聚合物胶束的水动力学直径在 100-200nm 范围内,且功能化样品在考虑的 pH 范围内没有聚集。通过最小 85%的比例实现了高的包封效率。药物释放曲线和 Peppas 模型的线性化证实了甲氨蝶呤与共聚物疏水性链段的相互作用及其通过链的松弛和/或降解的释放机制,使 PEG-b-PCL 胶束成为疏水性药物传递系统的合适候选物。
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