Stability and aggregation studies of non-sonicated arsonolipid-containing vesicles.
In this study, we investigated non-sonicated arsonolipid-containing liposomes (arsonoliposomes) in terms of the influence of lipid composition on their stability, assessed as membrane integrity and physical stability [size]. Vesicles consisting of plain arsonolipids or mixtures of arsonolipids with cholesterol [Chol] or with distearoyl-phospatidylcholine [DSPC] were studied. Membrane integrity was evaluated by measuring the retention of incorporated 5-(6)carboxyfluorescein [CF] during incubation of the vesicles in Tris buffer, pH 7.4. Photon correlation spectroscopy was used to investigate the time-dependent aggregation of arsonoliposomes in the absence and presence of Ca(2+)ions. Vesicles composed of plain C18 (acyl fatty chain) arsonolipids were found to be unstable, with only 15% of the initially incorporated CF remaining in the vesicles after 24 hours. The addition of Chol to the membrane (1:1 mol/mol) significantly increased the stability of arsonoliposomes, while the addition of DSPC to the lipid bilayer (1:1 mol/mol) increased vesicle stability to a lower extent. The results of particle size analysis showed that non-sonicated arsonoliposomes consisting of plain arsonolipid Ars/Stearic are highly and rapidly aggregated, while calcium-induced aggregation is also significant, but slower. Aggregation could not be always explained on the basis of zeta potential changes, indicating that the process is complex.
Fatouros
Dimitrios G
DG
Laboratory of Pharmaceutical Technology, Department of Pharmacy, University of Patras, 26504, Greece. df@dfuni.dk
Bouropoulos
Nikolaos
N
Ioannou
Panayiotis V
PV
Antimisiaris
Sophia G
SG
D001152:Arsenicals / Q000737:chemistry / Q000378:metabolism*; D002122:Calcium Chloride / Q000378:metabolism; D004075:Diglycerides / Q000737:chemistry / Q000378:metabolism*; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors
D001152:Arsenicals; D004075:Diglycerides; D008081:Liposomes; C054806:arsonic acid; D002122:Calcium Chloride