ABSTRACT
Pharmaceutical research on polymeric micelles has mainly focused on two kinds of block copolymers, namely, AB block copolymers or diblock copolymers and ABA or BAB block copolymers known as triblock copolymers. Copolymers are defined as polymers composed of several different monomer units and are classified into four types by monomer organization: random copolymers, alternating copolymers, graft copolymers, star copolymers, and block copolymers. This chapter describes the process of micellization for amphiphilic copolymers that is similar to the process described for conventional hydrocarbon chain-based surfactants. The micellization of amphiphilic copolymers can result in two different types of micelles, depending on whether the hydrophobic portion is randomly bound to the hydrophilic polymer or grafted to one end of the hydrophilic portion. The hydrophobic inner core of the micelle contains water-insoluble drugs, while the Poly (N--isopropylacrylamide) outer shell plays a role of stabilization and temperature-response. The technology enables development of pharmaceutically acceptable formulations with enhanced stability and improved bioavailability of highly water-insoluble drugs.
