Amphiphilic Block Copolymer Based Nanocarriers for Drug and Gene Delivery - Intracellular Delivery: Fundamentals and Applications - page 251

Amphiphilic Block Copolymer Based
Nanocarriers for Drug and Gene Delivery
Xiao-Bing Xiong and Afsaneh Lavasanifar
Abstract The use of amphiphilic block copolymers (ABC)s in experimental
medicine and pharmaceutical sciences has a long history and is expecting rapid
development. Poly(ethylene oxide)- block -poly(amino acid) and poly(ethylene
oxide)- block -polyesters represented the most important two types of ABCs for
development of nanocarriers for drug/gene delivery. In this chapter, we provided
an update on several chemical strategies used to enhance the properties of nano-
scopic core/shell structures formed from self assembly of ABCs, namely polymeric
micelles. Versatility of polymer chemistry in ABCs provides unique opportunities
for tailoring polymeric micelles for optimal properties in gene and drug delivery.
Chemical modification of the polymer structure in the micellar core through
introduction of hydrophobic or charged moieties, conjugation of drug compatible
groups, core cross-linking has led to enhanced stability for the micellar structure
and sustained or pH-sensitive drug release. The modification of polymeric micellar
surface with specific ligands (carbohydrates, peptides, antibodies) has shown benefits
in enhancing the recognition of carrier by selective cells leading to improved drug
and gene delivery to the desired targets. Research in drug delivery by polymeric
vesicles is still in its infancy, but a similar principle on the importance and benefit
of chemical flexibility of block copolymers in improving the delivery properties of
polymeric vesicles can also be envisioned. The demanding challenge of the future
research in this field is to find the right carrier architecture and optimum polymer
chemistry that can improve the delivery of sophisticated and complex therapeutic
agents (e.g., poorly soluble drugs, proteins and genes) to their cellular and intracel-
lular targets.
Keywords Polymeric micelles • Drug delivery • Nanocarriers • Amphiphilic block
copolymers • Gene delivery • Drug targeting
X.-B. Xiong and A. Lavasanifar ( * )
Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta,
Edmonton, AB T6G 2N8, Canada
e-mail: [e-mail]