Er Yan, Barnes Timothy J, Fornasiero Daniel, Prestidge Clive A
Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA, Australia.
J Liposome Res. 2009;19(1):29-36. doi: 10.1080/08982100802673940.
The encapsulation and release kinetics of guanosine from liposomes and polyethylene glycol (PEG)-modified liposomes are reported. Specifically, the influence of PEG chain length, PEGylation level, lipid type, drug-loading level, temperature, and solution conditions (i.e., salt and pH effects) on the rate and mechanism for release have been determined. Increasing PEGylation significantly reduced the guanosine release kinetics; this is more significant for greater molecular weight PEG and is correlated with the PEG layer thickness. Further, the mechanism for guanosine release changed from diffusion to interfacial control as the PEG level increased. The interfacial structure introduced by PEG also increased the activation energy required for guanosine transport across the lipid bilayer from 14 to 22 kJ mol(-1). Findings from this study provide further insight into optimizing the formulation of Stealth liposomes.
报道了鸟苷从脂质体和聚乙二醇（PEG）修饰脂质体中的包封及释放动力学。具体而言，已确定了PEG链长、聚乙二醇化水平、脂质类型、载药水平、温度和溶液条件（即盐和pH值的影响）对释放速率和机制的影响。聚乙二醇化程度的增加显著降低了鸟苷的释放动力学；对于分子量更大的PEG，这种影响更为显著，且与PEG层厚度相关。此外，随着PEG水平的增加，鸟苷的释放机制从扩散转变为界面控制。PEG引入的界面结构还使鸟苷跨脂质双层运输所需的活化能从14 kJ mol(-1)增加到22 kJ mol(-1)。本研究结果为优化隐形脂质体的配方提供了进一步的见解。
