Abstract
Liposomes and surfactant vesicles were characterized as potential drug carriers in this work. Iodide ion permeabilities, extent of drug entrapment and leakage were determined for liposomes. The chemically simpler, although lesser known, surfactant vesicles were characterized more exhaustively. Rates of iodide ions efflux from dipalmitoyl-D ,L- α-phosphatidylcholine, DPPC, liposomes were determined by iodide ion selective electrode. Initial rates of iodide ion efflux ranged from 7.5 x 10 ⁻⁶ to 4.2 x 10⁻⁵ mM/min in absence and in presence of 0.1 M NaCl, in the dialysate, respectively. Rates of iodide ion influx into DPPC liposomes were determined by fluorescence techniques. For the latter measurements, fluorescence quenching of DPPC liposomes entrapped ethyl [N -{4-(l-pyrene)butanoyl}]-6-amino hexanoate, pyrene derivative, by iodide ion, localized initially outside of the vesicles, were determined. In a separated experiment stability of DPPC liposomes to long term storage was determined. These liposomes remained stable after 15 days of storage a t 4°C. Formation of closed, stable, predominantly single bilayer vesicles from dioctadecyldimethylammonium chloride, DODAC, were unequivocally observed by electron microscopy. The diameters ranged from 250-500A (Degree symbol above A). DODAC vesicles also formed in the presence of cholesterol..
Romero-Mella, Alejandro Francisco (1978). Physical chemical characterization of amphiphilic vesicles and drug entrapment therein. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -235385.