Tonegawa Asato, Tamura Atsushi, Yui Nobuhiko
Department of Organic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062, Japan.
ACS Macro Lett. 2019 Jul 16;8(7):826-834. doi: 10.1021/acsmacrolett.9b00280. Epub 2019 Jun 19.
Acetylated α-cyclodextrin (α-CD)/poly(ethylene glycol) (PEG)-based polyrotaxanes (Ac-PRXs) with varying degrees of acetylation (DA) and molecular weight of axle PEG were synthesized and their solubility in aqueous solutions was investigated. Ac-PRXs with low DA (less than 35%) were dissolved in aqueous solutions without considering the molecular weight of axle PEG, whereas Ac-PRXs with high DA (more than 40%) and low molecular weight of axle PEG (less than 35000) were precipitated into the solutions. Interestingly, Ac-PRXs with high DA and high molecular weight of axle PEG (100000) exhibited a colloidal dispersion in aqueous solutions. It is considered that the threaded acetylated α-CDs formed hydrophobic microenvironments via hydrophobic interactions and the noncovered segments of axle PEGs provided colloidal stability. Furthermore, the potential application of Ac-PRX as a drug carrier was examined and it was established that Ac-PRX can encapsulate a hydrophobic drug. Accordingly, acetylation of PRXs is a viable approach to promote solubility in aqueous solutions and prepare self-assembled nanoparticles.
合成了具有不同乙酰化度（DA）和轴状聚乙二醇（PEG）分子量的乙酰化α-环糊精（α-CD）/聚乙二醇（PEG）基聚轮烷（Ac-PRXs），并研究了它们在水溶液中的溶解性。低DA（小于35%）的Ac-PRXs可溶解于水溶液中，而不考虑轴状PEG的分子量，然而，高DA（大于40%）且轴状PEG分子量低（小于35000）的Ac-PRXs会沉淀到溶液中。有趣的是，高DA且轴状PEG分子量高（100000）的Ac-PRXs在水溶液中呈现胶体分散状态。据认为，带螺纹的乙酰化α-环糊精通过疏水相互作用形成疏水微环境，轴状PEG的未覆盖部分提供了胶体稳定性。此外，还研究了Ac-PRX作为药物载体的潜在应用，并确定Ac-PRX可以包封一种疏水药物。因此，聚轮烷的乙酰化是提高在水溶液中的溶解度和制备自组装纳米颗粒的一种可行方法。
