ABSTRACT

In the recent two decades, development of efficient delivery systems for biological agents, such as low molecular mass drugs and biomacromolecues (DNA, proteins, etc.), has attracted tremendous attention. It is believed that such systems will help to overcome enormous barriers encountered by these agents on target sites, as well as increase solubility and stability of these agents. Synthetic polymers are among the major materials used in drug and gene delivery systems (1). One important and promising example of such materials is Pluronic

block copolymers. Pluronic block copolymers have 577

been used in experimental medicine and pharmaceutical sciences for a long time (see for review Refs. 2-11). The current chapter focuses on the relatively dilute isotropic solutions of block copolymers in aqueous media. These solutions exist in the form of either molecular dispersion or as micelles of the block copolymers. They can be used as solubilizers for insoluble drugs as well as nanocontainers for site-specific drug delivery in body. The distinct properties of Pluronic block copolymers can also enhance drug performance by acting as biological response-modifying agents, which act directly upon the target cells. Very recently, Pluronic block copolymers have shown promising potential for the non-viral gene delivery.