Characterization of liposomal vesicles encapsulating rhodanese for cyanide antagonism.

The major mechanism of removing cyanide from the body is its enzymatic conversion by a sulfurtransferase, e.g. rhodanese, to the less toxic thiocyanate in the presence of a sulfur donor. Earlier results demonstrated that externally administered encapsulated rhodanese significantly enhances the in vivo efficacy of the given sulfur donor. Present studies are focused on liposomal carrier systems encapsulating rhodanese. Physicochemical properties, e.g. membrane rigidity, size distribution, surface potential, osmolarity, and viscosity, were determined for various liposomal lipid compositions and hydrating buffers to establish in vitro stability and in vivo fate. Lipid composition was also optimized to achieve maximum encapsulation efficiency.

Liposomal oxytetracycline and doxycycline: studies on enhancement of encapsulation efficiency.

Liposomal encapsulations of oxytetracycline (OTC) and doxycycline (DC) with various lipid compositions and hydrating solutions have been studied in order to develop a new liposomal formulation to treat bacterial infections. Encapsulation efficiencies as a function of pH (pH 4.0-8.0) in ionic (phosphate buffers) and non-ionic (mannitol or glucose) hydrating solutions with various lipid compositions (lecithin or α-L-dipalmitoylphosphatidylcholine, with or without cholesterol) were determined and compared to the character of lipid vesicles. Based on our encapsulation efficiency studies and on the drug stability considerations it can be concluded that for OTC/DC encapsulation the use of non-ionic solutions is the most promising.