A Brief Review on Polymeric Nanomicelles for Anticancer Drug Delivery

Micelles are self-assembling, highly stable, biodegradable and biocompatible nanosized (5-200 nm) colloidal particles with amphiphilic copolymers (with a hydrophobic core and hydrophilic shell). These are currently used as pharmaceutical carriers for water-insoluble drugs and demonstrates a series of attractive properties as anticancer drug carriers. Among polymeric micelles, a special group is formed by lipid-core micelles, i.e., micelles formed by conjugates of soluble copolymers with lipids such as polyethylene glycol and phosphatidyl ethanolamine conjugate. Polymeric micelles, including lipid core micelles, carrying various contrast agents may become the imaging agents of choice in different imaging modalities and can also be used as targeted drug delivery systems. The targeting can be achieved via the enhanced permeability and retention effect (into the areas with the compromised vasculature), by making micelles of stimuliresponsive amphiphilic block-copolymers, or by attaching specific targeting ligand molecules to the micelle surface. Due to their hydrophilic shell and small size, they sometimes exhibit prolonged circulation times in vivo and can accumulate in tumoral tissues. This review will discuss some recent trends in using micelles as pharmaceutical carriers. Potential medical applications, especially in cancer chemotherapy, are described and discussed.