Physical Stability of Sonicated Arsonoliposomes: Effect of Calcium Ions

Incorporation of PEG-lipids in arsonoliposomes results in formation of highly stable arsenic-containing vesicles

“…Regarding the mechanism of calcium-induced aggregation, non-pegylated arsonoliposomes were previously demonstrated (by turbidity measurements and cryoelectron microscopy observation) to aggregate and sub- sequently fuse into larger vesicles (Fatouros et al, 2005). An easy method to distinguish between simple aggregation (formation of loose aggregates) and fusion involves measuring the vesicle turbidity in calcium, before and after the addition of excess amounts of EDTA (Siegel, 1993).…”

“…This was the case for arsonoliposomes which were reported to aggregate and subsequently fuse in the presence of CaCl 2 (Fatouros et al, 2005). In order to see whether pegylation affects self-or calcium-induced aggregation of arsonoliposomes, pegylated and non-pegylated arsonoliposomes, with low content arsonolipid (20%) and high content arsonolipid (27%) were evaluated.…”

“…As liposome size increases, their clearance from the bloodstream is faster (Senior, 1987). And while sonicated arsonoliposomes are small vesicles (their mean diameter is about 100 nm), the fact that they have recently been demonstrated to aggregate and fuse in the presence of calcium ions (Fatouros et al, 2005), may also be implicated in their rapid clearance. Indeed, it is possible that a rapid size increase of arsonoliposomes occurs (due to the presence of Ca 2+ ions) after in vivo injection.…”

Towards boron neutron capture therapy: The formulation and preliminary in vitro evaluation of liposomal vehicles for the therapeutic delivery of the dequalinium salt of bis-nido-carborane

“…19 For self-aggregation studies and for calcium-induced aggregation studies, boron-containing liposomes were respectively subjected to serial dilutions with pure water or with solutions of calcium chloride (final calcium concentration 1.8 mM) to a final lipid concentration of 0.065 mM. [Calcium concentrations were somewhat lower than those in plasma (>2 mM) to allow for the proportion of Ca 2+ that is strongly associated with serum proteins].…”

Thermal behavior of novel non-sonicated arsonolipid-containing liposomes

“…The possibility of combining the demonstrated antileukemic activity of arsenic containing compounds [4] with the ability of liposomes to deliver cytotoxic drugs in an activity-enhancing and toxicity-reducing manner was the rationale for developing arsonolipid-containing liposomes. Up to date, several types of arsonoliposomes have been prepared and their size, surface charge, morphology, physical stability and membrane integrity characteristics have been evaluated [5][6][7][8]. In vitro studies with some of the arsonoliposomes have shown different toxicity levels against cancer and normal cells [9,10] as well as substantial anti-parasitic activity [11].…”