LIPOSOMES WITH ALPHA-TOCOPHEROL MEMBRANE

Liposomes, closed spherical structures formed by phospholipid bilayers , have been recognized as a controlled drug delivery system. We have s tudied the preparation and biocompatibility of liposomes based on soya phospholipids encapsulated with alpha-tocopherol. The binding efficie ncy of alpha-tocopherol was analysed by comparing two methods for lipo some preparation: a) dry film (DFM) and b) solvent infusion method (SI M). The degree of encapsulation achieved (88-93%) suggested a high aff inity of alpha-tocopherol for liposome membrane binding. The initial c oncentration of alpha-tocopherol had a significant effect on the degre e of encapsulation, while the effect of method used was less pronounce d. In general, a higher degree of encapsulation was achieved with smal ler liposome size fractions. Based on an experimentally obtained size distribution function, it can be concluded that if smaller liposomes a re used, SIM seems to be more efficient due to the higher content of s maller vesicles. The in vivo application of the liposomes to CBA mice confirmed the biocompatibility and nontoxicity of such preparations. T he analysis of hematological parameters in peripheral blood (determina tion of mature blood cells with differential count) revealed that lipo somes did not express cytotoxic effects on any of the parameters teste d.