Polymer-bearing small unilamellar (SUV) liposomes were prepared by incorporating an uncharged polymer [hydrolyzed poly(vinyl alcohol) (PVA), poly(vinyl alcohol-co-vinyl acetal) (PVA-Al), poly(vinyl alcohol-co-vinyl propional) (PVA-Prol) poly(vinyl alcohol-co-vinyl butiral) (PVA-Bul) copolymer or poly(vinyl pyrrolidone) (PVP)] into the membrane bilayer of vesicles. The kinetic (long-term) stability of the liposome dispersions stored at 5°C and 40°C in distilled water, in physiological NaCl solution and at various pH values, respectively, were studied. The physical stability of vesicles was tested by measuring the size and the zeta potential of liposomes by means of a Malvern Zetasizer 4 apparatus. It was shown that most of these polymers are effective steric stabilizers for the DMPC-liposomes. Among the polymers, the poly(vinyl alcohol-co-vinyl butiral) and poly (vinyl alcohol-co-vinyl propional) copolymers and the PVP of high molecular mass exhibited the most efficient stabilizing effect at each pH studied, indicating that the formation of a relatively thick polymer layer around the lipid bilayers ensures an enhanced and prolonged physical stability of liposomes. Also, the butiral or propional side chain in the PVA-based copolymers presumably promotes the anchoring of macromolecules to the vesicles. Using these macromolecules, the colloidal interactions between vesicles can be modified and so the physical stability of liposomes and the kinetic stability of liposome dispersions can also be controlled.
|Translated title of the contribution||Stabilization of DMPC-liposomes by neutral polymers|
|Number of pages||7|
|Journal||Magyar Kemiai Folyoirat, Kemiai Kozlemenyek|
|Publication status||Published - Feb 1 1998|
ASJC Scopus subject areas