ABSTRACT
This chapter shows that all liposomes remain confined to the vasculature of the animal. That is, drug-bearing liposomes are unable to penetrate the endothelial barrier of capillaries except perhaps in liver. The liposome has been a prime candidate as a drug carrier with targeting potential. They are composed of naturally occurring phospholipids and cholesterol and are relatively easy to prepare. Although some therapeutic advantage is gained from such liposomes, a pressing need exists for a more specific targeting system. Liposomes being subjected to local hyperthermia might release most or only a small fraction of their contents during a single pass through the target site. The release kinetics of the liposome-drug system raises another consideration, that is, the choice of the drug to be associated with the liposomal carrier. Once injected into the circulatory system, the liposome encounters a number of factors that can rapidly compromise the thermotropic and/or structural properties of the liposome.
