• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4137-4140
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• 2012

A novel bioabsorbable suture material, poly(glycolide-caprolactone) (PGLCL) monofilament, was prepared by spinning of the PGLCL copolymer. The physical properties, strength retention, biocompatibility, and organism resolvability of the PGLCL monofilament were investigated. The results showed that the knot pull strength of the monofilament was higher than that stated in European Pharmacopoeia. The in vivo retention strength following implantation was 64%, 23%, 7%, and 0% after one, two, three, and four weeks, respectively. Mortality, clinical signs, validation, and sterility tests indicated that all items had passed. Organism resolvability tests showed that the PGLCL monofilament, as a suture, was absorbed within 91 days.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.523-528
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• 2005

Diblock copolymers with different poly($\varepsilon$-caprolactone) (PCL) block lengths were synthesized by ringopening polymerization of $\varepsilon$-caprolactone in the presence of monomethoxy poly(ethylene glycol) (mPEG-OH, MW 2000) as initiator. The self-aggregation behaviors of the diblock copolymer nanoparticle, prepared by the diafiltration method, were investigated by using $^1H$ NMR, dynamic light scattering (DLS), and fluorescence spectroscopy. The PEG-PCL block copolymers formed the nano-sized self-aggregate in an aqueous environment by intrsa- and/or intermolecular association between hydrophobic PCL chains. The critical aggregation concentrations (cac) of the block copolymer self-aggregate became lower with increasing hydrophobic PCL block length. On the other hand, reverse trends of mean hydrodynamic diameters were measured by DLS owing to the increasing bulkiness of the hydrophobic chains and hydrophobic interaction between the PCL microdomains. The hydrodynamic diameters of the block copolymer nanoparticles, measured by DLS, were in the range of 65-270 nm. Furthermore, the size of the nanoparticles was scarcely affected by the concentration of the block copolymers in the range of 0.125-5 mg/mL owing to the negligible interparticular aggregation between the self-aggregated nanoparticles. Considered with the fairly low cac and nanoparticle stability, the PEG-PCL nanoparticles can be considered a potential candidate for biomedical applications such as drug carrier or imaging agent.

• Textile Coloration and Finishing
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• v.22 no.3
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• pp.229-238
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• 2010

Poly($\varepsilon$-caprolactone) nano/microcapsules(nmcPCL) containing phytoncide oil were synthesized by emulsion diffusion method using ethyl acetate and poly(vinyl alcohol) (PVA) as an organic solvent and an emulsion stabilizer respectively. The influence of the degree of saponofication of the PVA and the weight ratio of core to wall materials was investigated to design nanocapsules in terms of particle size, morphology, and emulsion stability. The encapsulated nmcPCL were characterized by FT-IR spectrometry, particle size analyzer and scanning electron microscope. Mean size of nanocapsules prepared with PVA with a degree of saponofication of 87% was smaller than those of PVA with a degree of saponofication of 98.5% and the mean particle size of the capsules decreased with increasing core/shell ratio.

• Macromolecular Research
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• v.17 no.2
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• pp.72-78
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• 2009

Size control of therapeutic carriers in drug delivery systems has become important due to its relevance to biodistribution in the human body and therapeutic efficacy. To understand the dependence of particle size on the formation condition during nanoprecipitation method, we prepared nanoparticles from biodegradable, amphiphilic block copolymers and investigated the particle size and structure of the resultant nanoparticles according to various process parameters. We synthesized monomethoxy poly(ethylene glycol)-poly($\varepsilon$-caprolactone) block copolymer, MPEG-PCL, with different MPEG/PCL ratios via ring opening polymerization initiated from the hydroxyl end group of MPEG. Using various formulations with systematic change of the block ratio of MPEG and PCL, solvent choice, and concentration of organic phase, MPEG-PCL nanoparticles were prepared through nanoprecipitation technique. The results indicated that (i) the nanoparticles have a dual structure with an MPEG shell and a PCL core, originating from self-assembly of MPEG-PCL copolymer in aqueous condition, and (ii) the size of nanoparticles is dependent upon two sequential processes: diffusion between the organic and aqueous phases and solidification of the polymer.

• Bulletin of the Korean Chemical Society
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• v.22 no.5
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• pp.467-475
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• 2001

A triblock copolymer based on $poly(\varepsilon-caprolactone)$ (PCL) as the hydrophobic part and poly(ethylene glycol) (PEG) as the hydrophilic portion was synthesized by a ring-opening mechanism of ${\varepsilon}-caprolactone$ with PEG containing a hydroxyl group at bot h ends as an initiator. The synthesized block copolymers of PCL/PEG/PCL (CEC) were confirmed and characterized using various analysis equipment such as 1H NMR, DSC, FT-IR, and WAXD. Core-shell type nanoparticles of CEC triblock copolymers were prepared using a dialysis technique to estimate their potential as a colloidal drug carrier using a hydrophobic drug. From the results of particle size analysis and transmission electron microscopy, the particle size of CEC core-shell type nanoparticles was determined to be about 20-60 nm with a spherical shape. Since CEC block copolymer nanoparticles have a core-shell type micellar structure and small particle size similar to polymeric micelles, CEC block copolymer can self-associate at certain concentrations and the critical association concentration (CAC) was able to be determined by fluorescence probe techniques. The CAC values of the CEC block copolymers were dependent on the PCL block length. In addition, drug loading contents were dependent on the PCL block length: the larger the PCL block length, the higher the drug loading content. Drug release from CEC core-shell type nanoparticles showed an initial burst release for the first 12 hrs followed by pseudo-zero order release kinetics for 2 or 3 days. CEC-2 block copolymer core-shell type nanoparticles were degraded very slowly, suggesting that the drug release kinetics were governed by a diffusion mechanism rather than a degradation mechanism irrelevant to the CEC block copolymer composition.

• Macromolecular Research
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• v.13 no.5
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• pp.397-402
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• 2005

To explore the potential of shell crosslinked micelle (SCM) as a drug carrier, the drug release behavior of poly($\varepsilon$-caprolactone)-b-poly(acrylic acid) (PCL-b-PAA) SCMs was investigated. PCL-b-PAA was synthesized by ring opening polymerization of $\varepsilon$-caprolactone and atom transfer radical polymerization of tert-butyl acrylate, followed by selective hydrolysis of tert-butyl ester groups to acrylic acid groups. The resulting amphiphilic polymer was used to prepare SCMs by crosslinking of PAA corona via amidation chemistry. The drug release behavior of the SCMs was studied, using pyrene as a model drug, and was compared with that of non-crosslinked micelles, especially below the critical micelle concentration (CMC). When the shell layers were crosslinked, the drug release behavior of the SCMs was successfully modulated at a controlled rate compared with that of the non-crosslinked micelles, which showed a burst release of drug within a short time.

• Macromolecular Research
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• v.16 no.3
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• pp.231-237
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• 2008

Biodegradable poly($\varepsilon$-caprolactone-co-L-lactide)-b-poly(ethylene glycol) (PCLA-b-PEG) copolymers were synthesized via solution polymerization by varying the feed composition of $\varepsilon$-caprolactone ($\varepsilon$-CL) and L-lactide (LLA) ($\varepsilon$-CL: LLA= 10:0, 7:3, 5:5, 3:7, 0: 10). The feed ratio based on weight is in accordance with the copolymer composition except for the case of $\varepsilon$-CL: LLA=3:7 (C3L7), which was verified by $^1H$-NMR. Two different approaches were used for the exceptional case, which is an extension of the reaction time or the sequential introduction of the monomer. A copolymer composition of $\varepsilon$-CL: LLA=3:7 could be obtained in either case. The chemical microstructure of PCLA-b-PEG was determined using the $^{13}C$-NMR spectra and the effect of the sequential structure on the thermal properties and crystallinity were examined. Despite the same composition ratio of the copolymer, the microstructure can differ according to the reaction conditions.

• Macromolecular Research
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• v.15 no.1
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• pp.39-43
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• 2007

The amphiphilic block copolymer (PEtOz-PCL) of poly(2-ethyl-2-oxazoline) (PEtOz) and poly(${\varepsilon}$-caprolactone) (PCL) formed spherical micellar structures with an average diameter of 26 nm in aqueous phase. Au and Pd nanoparticles with an average diameter of $2{\sim}3nm$ were prepared by using the PEtOz-PCL micelle consisting of a PEtOz shell and PCL core. The Au nanoparticles of PEtOz-PCL micelles in aqueous phase could be transferred into organic phase by using n-dodecanethiol. The use of the Pd-NP/PEtOz-PCL micelle as a nanoreactor for Suzuki cross-coupling reaction was investigated.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.341-344
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• 2001

Over the last 20 years, biodegradable materials in medical applications have been studied extensively. Among these materials, poly(ε-caprolactone) and poly(trimethylene carbonate)(PTMC) are attractive biopolymers to be used as biodegradable sutures, artificial skin, drug release system. It was known that PCL is a nontoxic biocompatible semicrystalline polymer with melting point of 63℃, and PTMC is an amorphous or little crystaline polymer. (omitted)

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.588-593
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• 2005

In this study, biodegradable poly(${\varepsilon}$-caprolactone) (PCL) microcapsules containing chemically treated $SiO_2$ and nifedipine were prepared by oil-in-water (O/W) emulsion solvent evaporation method. The microcapsules containing drugs were confirmed using FT-IR spectra. The morphologies of the microcapsules were observed with scanning electron microscope (SEM). The nifedipine's release behaviors from the microcapsules were also examined with UV/vis spectroscopy. As a result, the inclusion of nifedipine into the microcapsules was determined by the presence of nifedipine's specific peak, i.e., C=O stretch vibration at $1682cm^{-1}$. The average particle size of the microcapsules decreased with increasing stirring rate. The nifedipine adsorption capacity and release rate of treated $SiO_2$ that was treated with basic solution decreased because with the increased basicity it lowered the specific surface area of $SiO_2$ and promoted stronger acid-base interactions between $SiO_2$ and nifedipine.