Acid-Triggered Transformation of Diortho Ester Phosphocholine Liposome
摘要:
The use of pH-sensitive liposomes for acid-triggered site-specific drug delivery is one of the more promising approaches to improve the therapeutic index of drugs. Here, we report the synthesis, assembly, and hydrolysis of the first ortho ester phosphocholine (OEPC). The acid hydrolysis of OEPC liposomes consists of a lag phase and a burst phase. The lag time is pH-dependent-the lower the pH, the shorter the time. Upon acid hydrolysis, the OEPC liposomes were transformed into leaky metastable vesicles that rapidly collapsed in the presence of albumin. OEPC, when formulated with cationic lipid, significantly enhanced the transfection efficiency compared with that of the pH-insensitive formulation.
A stabilized semi-solid delivery vehicle contains a polyorthoester and an excipient, and a pharmaceutical composition contains an active agent, optionally a stabilizing agent, and the delivery vehicle. The pharmaceutical composition may be a topical, syringable, or injectable formulation; and is suitable for local delivery of the active agent. Methods of treatment are also disclosed.
PEG-POE, PEG-POE-PEG, and POE-PEG-POE block copolymers
申请人:——
公开号:US20030152630A1
公开(公告)日:2003-08-14
PEG-POE, PEG-POE-PEG, and POE-PEG-POE block copolymers have both hydrophilic and hydrophobic blocks. They form micelles in aqueous solution, making them suitable for encapsulation or solubilization of hydrophobic or water-insoluble materials; and they also form bioerodible matrices for the sustained release of active agents, especially when the POE block(s) contain at least one unit containing an &agr;-hydroxy acid.
Chimeric immunomodulatory compounds and methods of using the same - III
申请人:——
公开号:US20030225016A1
公开(公告)日:2003-12-04
The invention provides immunomodulatory compounds and methods for immunomodulation of individuals using the immunomodulatory compounds.
这项发明提供了免疫调节化合物以及利用这些免疫调节化合物对个体进行免疫调节的方法。
Dendrimeric Alkylated Polyethylenimine Nano-carriers with Acid-Cleavable Outer Cationic Shells Mediate Improved Transfection Efficiency Without Increasing Toxicity
作者:Terry W. J. Steele、Wayne Thomas Shier
DOI:10.1007/s11095-010-0058-1
日期:2010.4
Improved polycation-based non-viral DNA vectors were sought by preparing dendrimers with polyethylenimine cores surrounded by various shells incorporating structural features intended to facilitate steps in transfection mechanisms. Dendrimeric vectors were designed with (a) an outer oligocation shell, intended to facilitate DNA release inside cells, (b) a hydrophobic C-16 alkyl shell, and (c) a polycationic core, the latter two intended to combine lipid-depletion and osmotic burst endosome escape mechanisms, respectively, and were (d) attached through an a acid-cleavable linker reported to hydrolyze at endosomal pH values. Vectors and DNA complexes were characterized by dynamic and static light scattering. Flow cytometry was used to quantitate transfection activity and cytotoxicity in CHO–K1 cells. About 5-fold increased transfection activity was obtained for a vector constructed with an outer shell of oligocations attached through acid-cleavable linkers, relative to a control dendrimer with an acid-stable linker. The most effective oligocation component of outer shells tested was spermine. Neither modification was associated with increased cytotoxicity. This vector design did not permit an evaluation of the benefit of combining endosome release mechanisms. Using acid-cleavable linkers to attach an outer shell of short, highly-charged oligocations to a PEI-based dendrimeric vector substantially increased transfection efficiency without increasing cytotoxicity.
通过制备具有聚乙烯亚胺核的树枝状聚合物,并在其周围包覆各种具有结构特征的外壳,以促进转染机制中的各个步骤,从而寻求改进的基于多阳离子的非病毒 DNA 载体。设计的树枝状载体(a)具有寡定位外壳,旨在促进 DNA 在细胞内的释放;(b)具有疏水的 C-16 烷基外壳;(c)具有多阳离子核心,后两者分别旨在结合脂质耗竭和渗透猝灭内体逃逸机制;(d)通过据报道在内体 pH 值下可水解的酸可分解连接体连接。通过动态和静态光散射对载体和 DNA 复合物进行了表征。流式细胞仪用于量化 CHO-K1 细胞中的转染活性和细胞毒性。与使用酸稳定连接体的对照树枝状聚合物相比,通过酸可分解连接体连接了寡定位外壳的载体的转染活性提高了约 5 倍。经测试,外壳中最有效的寡定位成分是精胺。这两种修饰都不会增加细胞毒性。这种载体设计无法评估结合内质体释放机制的益处。使用酸可分解连接体在基于 PEI 的树枝状聚合物载体上连接一个短的、高电荷的寡配位体外壳,可在不增加细胞毒性的情况下大幅提高转染效率。
Polymers containing poly(ester amides) and agents for use with medical articles and methods of fabricating the same
申请人:Pacetti D. Stephen
公开号:US20050265960A1
公开(公告)日:2005-12-01
Polymers containing poly(ester amides) and agents for use with medical articles and methods of fabricating the same are disclosed. The medical article generally comprises an implantable substrate having a coating, and the coating contains a polymer comprising a polymeric product of a reaction comprising a polyol, a polycarboxylic acid, an amino acid and an agent.