Nanoparticles for drug delivery -
Targeting controlled release polymer systems
July 13, 2014

Targeting controlled release polymer systems (TCRPS) , e.g., targeted to a particular tissue or cell type or targeted to
a specific diseased tissue but not normal tissue) have been developed recently. US Patent 8,603,501 teaches a
nanoparticle comprising: (a) an anticancer agent; (b) a diblock copolymer of (i) poly(ethylene glycol) and (ii) PLA or
PLGA; and (c) a prostate specific membrane antigen ligand conjugated to a diblock copolymer of (i) poly(ethylene
glycol) and (ii) polylactic acid (PLA) or poly(lactide-co-glycolide) (PLGA). And, US Patent 8,734,846 teaches a similar
nanoparticle composition but with at least one targeting agent is selected from antibodies, prostate specific membrane
antigen (PSMA) ligands and polypeptides that bind to epidermal growth factor receptor (EGFR), somatostatin receptor
(SSTR), insulin-like growth factor receptor, folic acid-receptor, HER2 receptor, interleukin-13receptor,
gastrin-releasing peptide receptor, CD30, vasoactive intestinal peptide receptor, gastrin receptor, prostate-specific
membrane antigen, and/or the estrogen receptor. Thus, TCRPS are specific (or effective) only to those cancer cells
with a receptor matching to targeting agent, but not those cancer cells with a receptor not-matching to the TCRPS
targeting agent. Thus, the application of TCRPS is narrow.

US Patent 8,591,877 describes a compound comprising an acetylated carboxymethylcellulose (CMC-Ac) covalently
linked to: at least one poly(ethylene glycol) (PEG), and at least one hydrophobic drug. Nanoparticles made of this
CMC-Ac-PEG-drug are relatively more specific to the cancer cells, rather than regular normal cells in animal studies. A
more specific system is available. Jingbin Huang et al, Biomaterials 35 (2014) 550-566, teaches self-assembled
nanoparticles of PLGA and hyaluronic acid (HA) copolymers for targeting docetaxel to breast cancer cells. In addition
to the similar charge properties to CMC-Ac, HA could specifically bind to its receptors CD44 and RHAMM (receptor for
HA-mediating motility) which are expressed in various cancer cells. Moreover, hyaluronic acid is subjected to
hyaluronidase degradation; resulting a porous structure of the nanoparticle. Consequently, it may be beneficial to
have alternative delivery systems available.


NOTE The above article is for reference use only, it is not a scientific publication. Though I put my best effort in the
preparation, this article may contain mistakes or out-of-date information. One should review recent publications from
scientific journals for details. All rights reserved. Thanks.

Keywords: hyaluronic acid