3 research outputs found

    Thermodynamic Study of Mixed Surfactants of Polyoxyethylene <i>tert</i>-Octyl Phenyl Ether and Dodecyltrimethylammonium Bromide

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    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

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    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

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    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 oligo­(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
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