Recent Progress in Polymer Therapeutics as Nanomedicines - Harnessing Biomaterials in Nanomedicine: Preparation, Toxicity, and Applications - page 102

itself to form a sphere around an aqueous core (Figure 4.1D). These
structures hold great advantage since the water-filled core allows
additional encapsulation of hydrophilic therapeutics, thus making
polymersomes an attractive vehicle for combination therapy. The
release of drugs from the aqueous core is achieved by slow diff usion
through the vesicle membrane or when the vesicle degrades and its
content is spilled. Like in micelles, the release can be environmentally
triggered by pH, temperature or redox changes. Ahmed et al.
[140] mixed inert PEG-polybutadiene diblock copolymer with
biodegradable PEG-PLA diblock copolymer (75:25 % respectively) to
form vesicles. Hydrophobic paclitaxel was encapsulated in the thick
polymeric membrane, while hydrophilic doxorubicin was trapped in
the aqueous core of the polymersomes, thus ensuring simultaneous
delivery. These polymersomes rapture at the endolysosome and were
shown to cause shrinkage of MDA-MB231 tumors in mice, while the
free drugs only slowed tumor growth [140]. Although this approach
is very elegant and promising, only few studies demonstrated drug
delivery using polymersomes.

Table 4.6 Examples of polymeric micelles and polymer-nucleic acid
complexes

Company Application Trade

name
(clinical
status)

Polymer

Polymeric micelles

Samyang Breast,

pancreatic and
advanced non-
small-cell lung
cancer

Genexol-
PM
(phase II)

mPEG-poly(D,L-
lactide)
encapsulating
paclitaxel

NanoCarrier Advanced solid

tumors

NK105
(Marketed
in Asia)

PEG-poly(aspartic
acid) block
copolymer-
paclitaxel

NanoCarrier Advanced solid

tumors

NC-6004
(Marketed
in Asia)

PEG-poly(glutamic
acid) block
copolymer-cisplatin