Synthesis of biodegradable poly(trans-4-hydroxy-N-benzyloxycarbonyl-l-proline)-block-poly(ε-caprolactone) copolymers and micellar characterizations

Lee, Ren-Shen; Li, Huarong; Yang, Jen‐Ming; Tsai, Fu-Yuan

doi:10.1016/j.polymer.2005.09.029

Cited by 12 publications

(5 citation statements)

References 25 publications

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“…The photophysical properties of pyrene are known to be strongly dependent on the polarity of its environment. 39 This feature has allowed using this fluorophore as a probe to determine critical micelle concentrations (CMC) for many nonionic and ionic amphiphilic block copolymers 28,[40][41][42][43][44][45][46][47][48][49][50] or polysoaps 51 in aqueous solutions.…”

Section: Methodsmentioning

confidence: 99%

“…The photophysical properties of pyrene are known to be strongly dependent on the polarity of its environment 39. This feature has allowed using this fluorophore as a probe to determine critical micelle concentrations (CMC) for many nonionic and ionic amphiphilic block copolymers28,[40][41][42][43][44][45][46][47][48][49][50] or polysoaps51 in aqueous solutions.Typical emission and excitation spectra of aqueous solutions of pyrene and PEO-b-PEA block copolymers at various concentrations are shown in Figure7. When the environment of pyrene changes from polar to nonpolar, both emission and excitation spectra are altered.…”

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confidence: 99%

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Self-Assembling Properties of Well-Defined Poly(ethylene oxide)-b-poly(ethyl acrylate) Diblock Copolymers

et al. 2009

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Poly(ethylene oxide)-b-poly(ethyl acrylate) amphiphilic diblock copolymers were synthesized by atom transfer radical polymerization (ATRP). The controlled character of the polymerization was confirmed by kinetic studies, evolution of number-average molecular weight and polydispersity index with conversion. Various block copolymers with different PEA/PEO molar ratio were synthesized and their self-assembling properties in aqueous medium were studied by fluorescence measurements, static light scattering (SLS), and dynamic light scattering (DLS). The critical micelle concentrations (CMC) were determined by pyrene fluorescence analysis. The CMC was shown to decrease as the hydrophobic (PEA) block length increases. SLS and DLS allowed the determination of the aggregation numbers (N agg ) and hydrodynamic radii (R h ) of the core-shell micelles formed in water. Both N agg and R h exhibit a monotonic increase as a function of the PEA block length. TEM and cryo-TEM micrographs of the micelles showed spherical objects with a low polydispersity of sizes. The micelles formed in water are in a thermodynamic equilibrium and the aggregation number of the micelles was shown to vary with the temperature.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Self-Assembling Properties of Well-Defined Poly(ethylene oxide)-b-poly(ethyl acrylate) Diblock Copolymers

et al. 2009

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“…The easier degradation of PCL‐ b ‐PHpr10‐ b ‐PCL5 may have been due to the smallest molecular weight and lowest molar fraction of the hydrophobic PCL block. The weight loss of PCL‐ b ‐PHpr‐ b ‐PCL was similar to that of the starred PHpr‐ b ‐PCL25 but lower than that of PHpr‐ b ‐PCL 26. Also, the changes in the molecular weight for these copolymers as a function of the immersion time were investigated.…”

Section: Resultsmentioning

confidence: 90%

“…In our earlier work, we reported the synthesis of two‐block star‐ and linear‐shaped poly( trans ‐4‐hydroxy‐ N ‐benzyloxycarbonyl‐ L ‐proline)‐ block ‐poly (ϵ‐caprolactone) (PHpr‐ b ‐PCL) copolymers with 1‐hexanol or trimethylolpropane as the initiator, respectively 25, 26. In this article, we describe the synthesis and micellar characterization of amphiphilic A–B–A triblock copolymers based on hydrophilic, dihydroxyl‐terminated, pseudo poly ( trans ‐4‐hydroxy‐ N ‐benzyloxycarbonyl‐ L ‐proline (PHpr) macroinitiators.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of biodegradable A–B–A triblock copolymers containing poly(ϵ‐caprolactone) A blocks and poly(trans‐4‐hydroxy‐L‐proline) B blocks

Lee¹,

Lin²,

Yang³

et al. 2006

J. Polym. Sci. A Polym. Chem.

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were synthesized by ring-opening polymerization from dihydroxyl-terminated macroinitiator poly(trans-4-hydroxy-N-benzyloxycarbonyl-L-proline) (PHpr) and e-caprolactone (e-CL) with stannous octoate as the catalyst. The molecular weights were characterized with gel permeation chromatography and matrix-assisted laser desorption/ionization timeof-flight mass spectrometry. With an increase in the contents of e-CL incorporated into the copolymers, a decrease in the glass-transition temperature (T g ) was observed. The T g values of copoly(4-phenyl-e-caprolactone) and copoly(4-methyl-e-caprolactone) were higher than T g of copoly(e-caprolactone). Their micellar characteristics in an aqueous phase were investigated with fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. The block copolymers formed micelles in the aqueous phase with critical micelle concentrations in the range of 1.00-1.36 mg L À1 . With higher molecular weights and hydrophobic components in the copolymers, a higher critical micelle concentration was observed. As the feed weight ratio of antitriptyline hydrochloride (AM) to the polymer increased, the drug loading increased. The micelles exhibited a spherical shape, and the average size was less than 250 nm. The in vitro hydrolytic degradation and controlled drug release properties of the triblock copolymers were also investigated. V V C 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: [4268][4269][4270][4271][4272][4273][4274][4275][4276][4277][4278][4279][4280] 2006

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“…The critical micelle concentration (cmc) was determined using pyrene as a fluorescence probe. 43 The fluorescence excitation spectra of pyrene were recorded by a Hitachi F-4600 fluorescence spectrophotometer (Hitachi High-Technologies Corporation, Tokyo, Japan). The emission wavelength was set at 390 nm.…”

Section: ■ Materialsmentioning

confidence: 99%

Preparation and Controlled Degradation of Model Amphiphilic Long-Subchain Hyperbranched Copolymers: Hyperblock versus Hypergraft

Yang

Li²,

Hao³

et al. 2019

Macromolecules

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The controlled degradation of amphiphilic hyperbranched polymers (AHPs) is the first consideration for their bio-related applications. In this contribution, we aim to get some insight into the effect of block distribution and composition on the degradation behavior of AHPs model systems. Degradable amphiphilic hyperbranched block (Hyperblock) and graft (Hypergraft) copolymers with hydrophobic poly(ε-caprolactone) (PCL) and hydrophilic poly[tri(ethylene glycol) methyl ether acrylate] (PTEGMA) as building blocks were prepared in this study, i.e., HB-PCL-b-PTEGMA and HB-PCL-g-PTEGMA. The two kinds of AHPs own cleavable disulfide linkages embedded at all branching sites. Their degradation behavior was comparatively investigated in aqueous solutions. The results reveal that the block distribution and composition play different roles in the regulation of degradation behavior of long-subchain hyperbranched self-assembly amphiphiles (SAs). Namely, the degradation process is mainly affected by chain architecture of resultant SAs, while for a given architecture, the degradation rate can be regulated by systematically varying the block composition.

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Synthesis of biodegradable poly(trans-4-hydroxy-N-benzyloxycarbonyl-l-proline)-block-poly(ε-caprolactone) copolymers and micellar characterizations

Cited by 12 publications

References 25 publications

Self-Assembling Properties of Well-Defined Poly(ethylene oxide)-b-poly(ethyl acrylate) Diblock Copolymers

Self-Assembling Properties of Well-Defined Poly(ethylene oxide)-b-poly(ethyl acrylate) Diblock Copolymers

Synthesis and characterization of biodegradable A–B–A triblock copolymers containing poly(ϵ‐caprolactone) A blocks and poly(trans‐4‐hydroxy‐L‐proline) B blocks

Preparation and Controlled Degradation of Model Amphiphilic Long-Subchain Hyperbranched Copolymers: Hyperblock versus Hypergraft

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