Polymerization of lactides and lactones. II. Ring-opening polymerization of ?-caprolactone andDL-lactide by organoacid rare earth compounds

Deng, Xianmo; Yuan, Minglong; Xiong, Chengdong; Li, X. H.

doi:10.1002/(sici)1097-4628(19990321)71:12<1941::aid-app2>3.0.co;2-e

Cited by 24 publications

(13 citation statements)

References 24 publications

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“…The 1 H-NMR spectrum of caprolactone shows peaks at 1.52, 2.35, and 4.12 ppm, which are assigned to methylene protons from (CH 2 ) 3 , CO-CH 2 , and CH 2 -O groups of the PCL chains, respectively. These results are consistent with those previously reported [15,16]. 90%.…”

Section: Characterization Of Copolymerssupporting

confidence: 94%

Synthesis and Application of a Thermoplastic Plate of Poly(lactide-ε-caprolactone) for Radiation Therapy

et al. 2019

Biomolecules

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In this study, the poly(lactide-ε-caprolactone) (P(LA-CL)) copolymer is synthesized by ring-opening polymerization with glycol used as a molecular weight regulator to adjust the molecular weight of the polymer. The proton nuclear magnetic resonance spectroscopy and gel permeation chromatography (GPC) results demonstrate that the P(LA-CL) copolymer is successfully synthesized, and that the molecular weight can be controlled by the glycol content. The thermoplastic plate is processed with triallyl isocyanurate as a cross-linking agent by a single-screw extruder followed by γ-ray irradiation. Shape memory test results show that the material had the desired shape memory effect, with deformation recovery rates reaching 100%. After secondary stretching of samples, deformation recovery rates are unchanged. The results of mechanical property measurements indicate that with added lactide, the tensile strength is improved and shore hardness is increased by 20%–30%. Data from clinical trials also reveal that the material has good clinical effects in thermoplastic membrane fixation.

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Section: Characterization Of Copolymerssupporting

confidence: 94%

Synthesis and Application of a Thermoplastic Plate of Poly(lactide-ε-caprolactone) for Radiation Therapy

et al. 2019

Biomolecules

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“…PDLLA with molecular weight of 52 kDa was synthesized in our lab 19. The molecular weight was determined by gel permeation chromatography (GPC, Waters 2695 and 2414, Milford, MA) using polystyrene beads as standard.…”

Section: Methodsmentioning

confidence: 99%

The effect of process parameters on the size and morphology of poly(D,L‐lactide‐co‐glycolide) micro/nanoparticles prepared by an oil in oil emulsion/solvent evaporation technique

Mahdavi

Mirzadeh

Hamishehkar

et al. 2009

J of Applied Polymer Sci

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For the past few decades, there has been a considerable research interest in the area of biodegradable polymeric micro-and nanoparticles for tissue engineering, regenerative medicine, implants, stents, medical devices, and drug delivery systems. Poly(D,L-lactide-coglycolide) (PLGA) is well-known by its safety in biomedical preparations which has been approved for human use by the FDA. The goal of this study was to evaluate the influence of process parameters on size characteristics of PLGA microparticles prepared by oil in oil (o/o) solvent evaporation technique. This method has been introduced as one of the most appropriate methods for hydrophilic agents. Scanning electron microscopy showed that prepared particles were spherical with smooth surface without aggregation. Particle size varied from 570 nm to 29 lm in different experimental conditions. Stirring speed, polymer concentration, impeller type, and dropping size had a significant effect on the particle size. The polydispersity index of particles showed a strong relationship with the surfactant concentration, impeller type, and dropping size. It was concluded that increasing in temperature up to 50 C or changing in dropping rate has a little effect on reducing the size of PLGA particles. The residual solvent content in the final suspension was less than 0.1 ppm that is in appropriate range for biomedical application.

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“…PDLLA with molecular weight of 52 kDa was synthesized in our lab. 19 The molecular weight was determined by gel permeation chromatography (GPC, Waters 2695 and 2414, Milford, MA) using polystyrene beads as standard. The column used was a Styragel HT 4 (7.8 3 300 mm).…”

Section: Methodsmentioning

confidence: 99%

Structural stability and release profiles of proteins from core‐shell poly (DL‐lactide) ultrafine fibers prepared by emulsion electrospinning

Yang

Cui

et al. 2007

J Biomedical Materials Res

123

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This study was aimed at assessing the potential use of emulsion electrospinning to prepare core-shell structured ultrafine fibers as carriers for therapeutic proteins. It focused on the effect of fiber structure on the release profiles and structural stability of encapsulated proteins. In the case of bovine serum albumin (BSA) which was selected as a model protein, poly-DL-lactide ultrafine fibers prepared by emulsion electrospinning using a lower volume ratio of aqueous to organic phase, showed higher structural integrity of core-shell fiber as assessed by laser confocal scanning microscope (LCSM). This structural property can reduce the initial drug burst and improved the ability of the device to provide sustained therapeutic action. Fickian release was observed for the initial 60% of protein release. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) were used to assess the primary structure of BSA. These studies indicated that ultra-sonication caused denaturation of protein molecules, while the core-shell structured electrospun fibers protected the structural integrity of encapsulated protein during incubation in the medium. Fourier transform infrared (FTIR) analyses showed that the electrospinning process had much less effect on the secondary structure of protein than ultra-sonication. In vitro degradation study showed that the protein release from fibers led to more significant mass loss, higher molecular weight reduction and larger molecular weight distribution of the matrix residues, compared with fibers without protein inoculation. These data suggest that emulsion electrospinning can provide a useful core-sheath structure, which may serve as a promising scaffold for sustainable, controllable, and effective release of bioactive proteins in tissue engineering and other applications.

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Polymerization of lactides and lactones. II. Ring-opening polymerization of ?-caprolactone andDL-lactide by organoacid rare earth compounds

Cited by 24 publications

References 24 publications

Synthesis and Application of a Thermoplastic Plate of Poly(lactide-ε-caprolactone) for Radiation Therapy

Synthesis and Application of a Thermoplastic Plate of Poly(lactide-ε-caprolactone) for Radiation Therapy

The effect of process parameters on the size and morphology of poly(D,L‐lactide‐co‐glycolide) micro/nanoparticles prepared by an oil in oil emulsion/solvent evaporation technique

Structural stability and release profiles of proteins from core‐shell poly (DL‐lactide) ultrafine fibers prepared by emulsion electrospinning

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