Encapsulation of a Hydrophobic Drug into a Polymer-Micelle Core Explored with Synchrotron SAXS
Encapsulation of a Hydrophobic Drug into a Polymer-Micelle Core Explored with Synchrotron SAXS
复制标题
DOI：
10.1021/la904355p
复制
发表时间：
2010-05-18
期刊：
影响因子：
3.9
通讯作者：
Yagi, Naoto
中科院分区：
文献类型：
--
作者：
Akiba, Isamu;Terada, Naotaka;Yagi, Naoto
在SPring-8 40 B2和45 XU光束线处对（PEG-P（Asp（Bzl）的水溶液进行同步加速器小角X射线散射（SAXS）：部分苄基酯化的聚（乙二醇）-嵌段-聚（天冬氨酸），其中LE 540负载高达8.3wt%，其中LE 540是非常疏水的类维生素A拮抗剂药物。散射曲线显示了核壳球形胶束的特征，证实P（Asp（Bzl））形成疏水核，PEG形成亲水壳。在添加LE 540之前，在q = 4 nm（-1）附近观察到衍射峰，其中q是散射矢量的大小。该峰可归因于由P（Asp（Bzl））构成的α-螺旋之间的有序化，即所谓的非特异性六角排列。当加入LE 540时，P（Asp（Bzl））螺旋消失。这一结果可以通过假设LE 540在堆芯中均匀分布来解释。通过使用核壳球形胶束模型，SAXS数据可以很好地拟合所有样品。分析表明，在加入LE 540后，核半径从5.9 nm S形增加到6.9 nm，而壳半径保持在12.5-12.8 nm。作为由一个胶束组成的PEG-P（Asp（Bzl））的平均数的聚集数从145略微增加到182。
Synchrotron small-angle X-ray scattering (SAXS) at the SPring-8 40B2 and 45XU beamlines was carried out on aqueous solutions of (PEG-P(Asp(Bzl))): partially benzyl-esterified poly(ethylene glycol)-block-poly(aspartic acid) with LE540 loaded up to 8.3 wt %, where LE540 is a very hydrophobic retinoid antagonist drug. The scattering profiles showed characteristic features for core-shell spherical micelles, confirming that P(Asp(Bzl)) forms a hydrophobic core and PEG forms a hydrophilic shell. Before the addition of LE540, a diffraction peak was observed around q = 4 nm(-1), where q is the magnitude of the scattering vector. This peak can be attributed to ordering between a-helices made of P(Asp(Bzl)), the so-called nonspecific hexatic arrangement. The P(Asp(Bzl)) helices disappeared as LE540 was added. This result can be interpreted by assuming a uniform distribution of LE540 in the core. By use of a core shell spherical micelle model, the SAXS data could be well fitted for all of the samples. The analysis indicated that the core radius increases sigmoidally from 5.9 to 6.9 nm upon addition of LE540 whereas the shell radius stayed at 12.5-12.8 nm. The aggregation number that is the average number of PEG-P(Asp(Bzl))'s consisting of one micelle slightly increased from 145 to 182.