Enzymatic degradation of polymer covered SOPC-liposomes in relation to drug delivery

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Polyethylenoxide (PEG) covered liposomes are used as lipid-based drug-delivery systems. In comparison to conventional liposomes the polymer-covered liposomes display a long circulation half-life in the blood stream. We investigate the influence of polyethyleneoxide-distearoylphosphatidylethanolamine (DSPE-PEG750) lipopolymer concentration on phospholipase A2 (PLA2) catalyzed hydrolysis of liposomes composed of stearoyloleoylphosphatidylcholine (SOPC). The characteristic PLA2 lag-time was determined by fluorescence and the degree of lipid hydrolysis was followed by HPLC analysis. Particle size and zeta-potential were measured as a function of DSPE-PEG750 lipopolymer concentration. A significant decrease in the lag-time, and hence an increase in enzyme activity, was observed with increasing concentrations of the anionic DSPE-PEG750 lipopolymer lipids. The observed decrease in lag-time might be related to changes in the surface potential and the PLA2 lipid membrane affinity.

Original languageEnglish
JournalAdvances in Colloid and Interface Science
Pages (from-to)303-311
Number of pages9
Publication statusPublished - 29 Jan 2001

ID: 236896632