PHOSPHATIDYL POLYGLYCEROLS PROLONG LIPOSOME CIRCULATION IN-VIVO

To obtain liposomes with longer circulation times in vivo, we newly sy nthesized dipalmitoylphosphatidylpolyglycerol (DPP-PG). A series of DP P-PGs of different chain lengths was used in this study. The individua l derivatives were incorporated into distearoylphosphatidylcholine/cho lesterol liposomes (1:1, molar ratio). The effectiveness of DPP-PG der ivatives was dependent on the amount and degree of polymerization. Low -polymerized PGs such as diglycerol and tetraglycerol needed a high in corporation rate of 8 mol%, while high-polymerized PGs such as octagly cerol required 4 mol%. The incorporation of 6 mol% of DPP-hexaglycerol was most effective in prolonging the circulation time of liposomes.