3 research outputs found
Thermodynamic Study of Mixed Surfactants of Polyoxyethylene <i>tert</i>-Octyl Phenyl Ether and Dodecyltrimethylammonium Bromide
Mixtures of polyoxyethylene <i>tert</i>-octyl phenyl
ether (TX100) and dodecyltrimethylammonium bromide (DTAB) were investigated
using isothermal titration calorimetry. On the base of the pseudophase
separation model and using the two-parameter Margules equation, the
compositions of mixed micelles and activity coefficient of each surfactant
in mixed micelles were obtained and further used to calculate the
thermodynamic parameters of micellization and excess properties of
mixed surfactants in the micelles. Through three titration methods,
the tendency of surfactants to form mixed micelles and the interactions
between TX100 and DTAB in the micelles were investigated
Optimization of Amphiphilic Miktoarm Star Copolymers for Anticancer Drug Delivery
The
preparation of various types of miktoarm star polymers with
precisely controlled structures (A<sub>2</sub>B, ABC, AB<sub>2</sub>C<sub>2</sub>, etc.) has made significant progress due to the considerable
advances in the synthetic strategies, including multistep protections/deprotections,
orthogonality, and integration of different polymerization techniques.
However, compared to the well-developed synthesis methodologies, the
investigations on miktoarm star copolymers as drug delivery vehicles
remain relatively unexplored, especially for the relationship of their
branched structures and properties as drug delivery systems. To elucidate
this structure–property relationship of amphiphilic miktoarm
star polymers, we prepared four different amphiphilic miktoarm star
copolymers with the respectively identical molecular weights (MWs)
of hydrophilic and hydrophobic moieties but different star structures
using heteroinitiators that were synthesized by protection/deprotection
strategies for integrated ring-opening polymerization of hydrophobic
ε-caprolactone and atom transfer radical polymerization of hydrophilic
oligo (ethylene glycol) monomethyl ether methacrylate (OEGMA). Further
screening of an optimal formulation for anticancer drug delivery by
the stability of micelles, in vitro drug loading capacity, drug release
properties, cellular uptake efficacy, and cytotoxicity of doxorubicin
(DOX)-loaded micelles showed that PCL<sub>3</sub>POEGMA<sub>1</sub> micelles possessed the lowest critical micelle concentration, the
highest drug loading content, and enhanced therapeutic efficiency
for DOX release of all the synthesized four star copolymer constructs.
This study thus provides preliminary guidelines and rationalities
for the construction of amphiphilic miktoarm star polymers toward
enhanced anticancer drug delivery
Fabrication of Hyperbranched Block-Statistical Copolymer-Based Prodrug with Dual Sensitivities for Controlled Release
Dendrimer
with hyperbranched structure and multivalent surface
is regarded as one of the most promising candidates close to the ideal
drug delivery systems, but the clinical translation and scale-up production
of dendrimer has been hampered significantly by the synthetic difficulties.
Therefore, there is considerable scope for the development of novel
hyperbranched polymer that can not only address the drawbacks of dendrimer
but maintain its advantages. The reversible addition–fragmentation
chain transfer self-condensing vinyl polymerization (RAFT-SCVP) technique
has enabled facile preparation of segmented hyperbranched polymer
(SHP) by using chain transfer monomer (CTM)-based double-head agent
during the past decade. Meanwhile, the design and development of block-statistical
copolymers has been proven in our recent studies to be a simple yet
effective way to address the extracellular stability vs intracellular
high delivery efficacy dilemma. To integrate the advantages of both
hyperbranched and block-statistical structures, we herein reported
the fabrication of hyperbranched block-statistical copolymer-based
prodrug with pH and reduction dual sensitivities using RAFT-SCVP and
post-polymerization click coupling. The external homo oligoÂ(ethylene
glycol methyl ether methacrylate) (OEGMA) block provides sufficient
extracellularly colloidal stability for the nanocarriers by steric
hindrance, and the interior OEGMA units incorporated by the statistical
copolymerization promote intracellular drug release by facilitating
the permeation of GSH and H<sup>+</sup> for the cleavage of the reduction-responsive
disulfide bond and pH-liable carbonate link as well as weakening the
hydrophobic encapsulation of drug molecules. The delivery efficacy
of the target hyperbranched block-statistical copolymer-based prodrug
was evaluated in terms of <i>in vitro</i> drug release and
cytotoxicity studies, which confirms both acidic pH and reduction-triggered
drug release for inhibiting proliferation of HeLa cells. Interestingly,
the simultaneous application of both acidic pH and GSH triggers promoted
significantly the cleavage and release of CPT compared to the exertion
of single trigger. This study thus developed a facile approach toward
hyperbranched polymer-based prodrugs with high therapeutic efficacy
for anticancer drug delivery