Physics Department, IBILCE/UNESP, São José do Rio Preto-SP, Brazil.
Langmuir. 2010 Dec 7;26(23):17852-7. doi: 10.1021/la102603a. Epub 2010 Nov 4.
A number of fundamental studies on the interactions between lipid bilayers and (ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide) copolymers (PEO-PPO-PEO, Pluronics) have been carried out recently as model systems for the complex behavior of cell membranes with this class of polymers often employed in pharmaceutical formulations. We report here a study by differential scanning calorimetry (DSC) of the interactions in water between Pluronic F127 (F127), and the cationic vesicles of di-n-octadecyldimethylammonium bromide (DODAB), as a function of concentration of the two components (DODAB 0.1 and 1.0 mM; F127 0.1 to 5.0 mM) and of the sample preparation protocol. The DSC studies follow the critical micellization temperature (cmt ≈ 27 °C at 1.0 mM) of F127 and the gel-liquid crystal transition (T(m) ≈ 45 °C) of the DODAB bilayer and of F127/DODAB mixtures. Upon heating past T(m), vesicle/polymer mixtures undergo an irreversible conversion into mixed DODAB/F127 micelles and/or F127-bearing vesicles, depending on the relative amount of each component, together with, in some cases, residual intact F127 micelles or DODAB vesicles. Sample preparation protocol is shown to have little impact on the composition of mixed systems once they are heated above T(m).
最近，人们对脂质双层与（氧化乙烯）-b-（氧化丙烯）-b-（氧化乙烯）共聚物（PEO-PPO-PEO，泊洛沙姆）之间的相互作用进行了大量基础研究，这些共聚物是模拟细胞膜复杂行为的模型体系，常被用于药物制剂中。我们在此报告一项差示扫描量热法（DSC）研究，研究内容是水相中的 F127（Pluronic F127）与二油酰基二甲基溴化铵（DODAB）阳离子囊泡之间的相互作用，研究变量包括两种组分的浓度（DODAB 为 0.1 和 1.0 mM；F127 为 0.1 至 5.0 mM）和样品制备方案。DSC 研究遵循 F127 的临界胶束化温度（cmt≈27°C，在 1.0 mM 时）和 DODAB 双层以及 F127/DODAB 混合物的凝胶-液晶转变（T(m)≈45°C）。加热超过 T(m)后，囊泡/聚合物混合物不可逆地转化为混合的 DODAB/F127 胶束和/或含有 F127 的囊泡，这取决于每种组分的相对量，在某些情况下，还会有残余的完整的 F127 胶束或 DODAB 囊泡。一旦加热到 T(m)以上，样品制备方案对混合体系的组成影响不大。
