ABSTRACT

The therapeutic oligonucleotides that are the most thoroughly investigated are the antisense oligodeoxynucleotides, and this is possibly because they have the simplest structures. Factors such as oligonucleotide stability, cellular uptake, subcellular availability, and other pharmacokinetic parameters lead to a relatively poor delivery to target molecular sites at doses amenable to an affordable treatment. The bipolar nature of phospholipid molecules used to form liposomes leads to the spontaneous formation, in excess water, of vesicles where hydrophilic heads face the external aqueous environment and hydrophobic tails face inward toward each other. Considering the vast array of phospholipids and other polar lipids, and the various methodologies used for liposome preparation, there is a huge potential diversity in liposome structure. Protection from the action of serum nucleases by liposomes may allow a ribozyme, or any other encapsulated nucleic acid therapeutic, time to accumulate at its intended site of action.