Many studies have been undertaken to understand the principles by which surfactants interact with phospholipid liposomes.1 Added surfactants can lead eventually to solubilization of the liposomes.2 Cationic large unilamellar liposomes from 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and didodecyldimethylammonium bromide (DDAB) or dioctadecyldimethylammonium bromide (DODAB) were prepared. The stability of these liposomal systems was evaluated fluorimetrically by monitoring at 25°C the rate of spontaneous (Figure 1) and surfactant-induced release of entrapped 5(6)-carboxyfluorescein (CF). The non-ionic surfactants Triton X-100 (TX-100) and octaethyleneglycol mono-n-dodecylether (C12E8) were used as the perturbing agents. The saturation (Rsat) and the solubilization (Rsol) ratios (Figure 2) of the prepared liposome systems have been measured spectrofotometrically at different surfactant concentrations. The results obtained show that the presence of DDAB and DODAB molecules into the liposomal bilayer stabilizes the liposomes and the extent of this stabilization depends of the concentration and the nature of the cationic surfactant.
The influence of bilayer composition on the kinetics of the Breakdown of cationic liposomes
ANGELINI, Guido;DE MARIA, Paolo;FONTANA, Antonella;GASBARRI, Carla;SIANI, Gabriella
2009-01-01
Abstract
Many studies have been undertaken to understand the principles by which surfactants interact with phospholipid liposomes.1 Added surfactants can lead eventually to solubilization of the liposomes.2 Cationic large unilamellar liposomes from 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and didodecyldimethylammonium bromide (DDAB) or dioctadecyldimethylammonium bromide (DODAB) were prepared. The stability of these liposomal systems was evaluated fluorimetrically by monitoring at 25°C the rate of spontaneous (Figure 1) and surfactant-induced release of entrapped 5(6)-carboxyfluorescein (CF). The non-ionic surfactants Triton X-100 (TX-100) and octaethyleneglycol mono-n-dodecylether (C12E8) were used as the perturbing agents. The saturation (Rsat) and the solubilization (Rsol) ratios (Figure 2) of the prepared liposome systems have been measured spectrofotometrically at different surfactant concentrations. The results obtained show that the presence of DDAB and DODAB molecules into the liposomal bilayer stabilizes the liposomes and the extent of this stabilization depends of the concentration and the nature of the cationic surfactant.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
