Amphiphilic Block Copolymer Based Nanocarriers for Drug and Gene Delivery - Intracellular Delivery: Fundamentals and Applications - page 255

PPG polypropylene glycol

PPPs polyphosphazenes

PPP-DMAE polyphosphazenes with 2-dimethylaminoethanol side groups

PPP-DMAEA polyphosphazenes with 2-dimethylaminoethylamine side groups

PSI poly(L-succinimide)

QDs quantum dots

RES reticuloendothelial system

RGD Arg-Gly-Asp

SANS small angle neutron scattering

SERS surface enhanced Raman spectroscopy

SPIO superparamagnetic iron oxide

SWCNTs single-walled CNTs

TM-Bz-CS quaternized N-(4-N,N-dimethylaminobenzyl) chitosan

TM-CS trimethylated CS oligomers

1 Introduction

The use of amphiphilic block copolymers (ABC)s in experimental medicine and
pharmaceutical sciences has a long history and is experiencing rapid develop-
ment. ABCs have been used as safer replacements for surfactants in the solubi-
lization of poorly soluble drugs, as stabilizing agents in the formulation of
coarse and colloidal dispersions, as gels providing depot or bioavailable formu-
lations and core/shell association colloids for nano-scale drug and gene delivery
(Lavasanifar et al. 2002a ; Lemieux et al. 2000 ; Osada and Kataoka 2006 ;
Bijsterbosch et al. 1999 ). The rapid development in the application of ABCs is
primarily due to several degrees of freedom in their chemistry that may be used
to design specific carriers for specific delivery applications. For instance, the
size of both the hydrophilic and the hydrophobic section can be varied at will;
the molecular weight of the polymer can be changed within a wide range while
maintaining constant hydrophilic-lipophilic balances; the properties and func-
tion of ABCs at interface, e.g. oil-water, can be controlled through changes in
polymer structure, and more importantly, both hydrophilic and hydrophobic sec-
tion can be chemically engineered towards specific application. In addition to
their application in the design of nano-delivery systems, ABCs are shown to
have biological effects, themselves (Kabanov et al. 2003 ; Zastre et al. 2004 ;
Todd et al. 1998 ).
The aim of this chapter is to provide an overview on the pharmaceutical application
of ABC based nanostructures. The emphasis will be placed on poly(ethylene
oxide)- block -poly(amino acids) and poly(ethylene oxide)- block -polyester based
polymeric micelles. Recent advancements in polymeric micellar drug/gene targeting
will be highlighted and related nanostructures formed from ABCs will be briefly
discussed.