Among nanosized drug delivery systems, liposomes and polymeric nanoparticles are the best-known and most widely used. Liposomes are spherical vesicular systems in which a core structure is surrounded by one or more phospholipid layers. Thus, in a sense, they are primitive versions of lipid-based drug delivery systems . They are fundamentally advantageous in many ways; production costs are generally low and manufacturing methods are extremely practical, to name a few. In this way, liposome-based products have been rapidly commercialized and have gained acceptance in both academia and industry. However, there are many issues related to physical and chemical stability that severely limit the in vivo performance of these drug delivery systems: e.g., (i) changes in vesicle size due to vesicle aggregation and fusion during storage, (ii) leakage of the loaded drug from the vesicle, and (iii) susceptibility of the (phospho)lipids to hydrolytic cleavage, which disrupts the integrity of liposomes, and to oxidation .