ABSTRACT
The evident drawback of liposomal preparations as potential carriers for biologically active compounds 1 is their fast elimination from the circulation and capture by the cells of the reticuloendothelial system (RES). The recognition and capture of liposomes occurs, primarily, in liver and spleen, and is believed to be the result of fast opsonization of liposomes with blood opsonins.2 To make liposomes capable of delivering pharmaceutical agents to targets other than the RES, attempts have been made to prolong their lifetime in the circulation, such as by variation of the liposome size,3 coating liposomes with some plasma proteins,4 and RES blockade by presaturation with empty liposomes before the application of "therapeutical" ones.5
