Liposomes PEG-coated

Recently, this method was adapted to label two commercially available liposomal formulations doxorubicin encapsulated in polyethylene glycol (PEG)-coated liposomes (Caelyx /Doxil ) (14) and daunorubicin encapsulated in small distearoyl-phosphatidyl-choline/cholesterol liposomes (Daunoxome ) (15). Although no DTPA was encapsulated in these liposomes, the labeling efficiency was typically between 70% and 80% and the radiolabeled preparations were stable in vivo during the time course of the experiment (four hours). Most likely, the lipophilic In-oxine avidly associates with the lipid bilayer and encapsulation of DTPA might not be necessary when the experimental observation period does not exceed four to six hours. 

Also known as Doxil PEG-coated liposome formulation with doxorubicin. 

Fig. 3. Schematic representation of interacting PEG-coated liposome bilayers bearing the recognizable biotin group with avidin molecules dissolved in water...

The possibility of using TNF encapsulated into long-circulating PEG-liposomes for the treatment of solid tumors, possibly, in combination with other cytotoxic agents was discussed in the literature. PEG-coated liposomes have also been proposed... 

The preformed vesicle (PFV) approach involves incubation of liposomes containing a cationic lipid and a PEG coating with polynucleotides in the presence of ethanol. Typically, LUV composed of distearoyl-phosphatidyl-choline (DSPC), cholesterol (Choi), l-0-(2 -(oi-methoxy-polyethylene-glycol)... 

The liposome biodistribution profile changes significantly when the vesicle surface [227-229] is coated with polymers, usually PEG. Longer blood circulation, lower liver uptake, and higher accumulation in tumors have been reported. The presence of the hydrophilic groups of PEG on the liposome surface provides electrostatic and steric repulsion between PEG-grafted liposomes. PEG molecules neutralize the surface charge of vesicles and thus prevent their opsonization. Also, liposome opsonization is reduced due to inability of opsonins to bind to hydrophilic surfaces. Moreover, the thickness of the PEG layer influences the interaction of the liposomes... 

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