ABSTRACT
Parenterally administered nanoscale drug delivery systems, including liposomes, albumin microspheres, micellar dispersions, dendrimers, polymeric nanoparticles, and polyplexes continue to show promise in improving the profile of selected anti-tumor drugs, which, given alone, suffer from unfavorable chemistry or pharmacologic properties and/or narrow safety margins (1-11). Yet, product introductions based on these technologies have been few. This chapter will update the history of one commercial success story in this category, pegylated liposomal doxorubicin (PLD), a product marketed in the United States under the trade name Doxil (Ortho Pharmaceuticals), and in the rest of the world as CAELYX (ScheringPlough). The clinical niche PLD now occupies, plus the growing understanding of its pharmacologic properties, provide insight into the desirable attributes and limitations of a solid-tumor delivery system and shed light on key challenges developers face in striking the delicate balance required to entrap, carry, selectively deliver, and release a drug at the intended site and at active concentrations in solid tumors.
