ABSTRACT
Poly (ethylene oxide) (PEO)-poly(ester) copolymers are biocompatible, biodegradable diblock polymers that spontaneously form core-shell nanoparticles in water. The hydrophobic polyester core of these micelles can solubilize small, hydrophobic drug molecules that have shown promise in the treatment of cancer and infectious diseases. In the context of micelle-based drug delivery, encapsulation efficiency and release are irrevocably related to the equilibrium between unimers and micelles in aqueous solution. Another common characterization is the critical-micelle concentrations, or the lowest concentration of copolymer required to form a micelle, which indirectly describes the equilibrium and stability. As micelles form, pyrene preferentially localizes in the core of the micelles, and the ratio increases in this less polar environment. The hydrophobic model drugs discussed until now utilized dialysis to remove free drug. Paclitaxel is a lipophilic small-molecule drug highly successful in the treatment of breast, ovarian, and lung cancers.
