Time filter

Source Type

Seoul, South Korea

Shim Y.-B.,CHA Medical University | Jung H.-H.,Yonsei University | Jang J.W.,Cellumed Co. | Yang H.S.,Dankook University | And 4 more authors.
Journal of Industrial and Engineering Chemistry | Year: 2016

Hollow porous poly(d,. l-lactide-co-glycolide) microspheres (HP-PLGA-MS) were manufactured using the water-in-oil-in-water double emulsion solvent evaporation method with sucrose as a novel porogen. Dexamethasone (DEX) was dissolved in the oil phase and loaded during the preparation of the HP-PLGA-MS. Bone morphogenetic protein-2 (BMP2) with type I collagen (Col1) was incorporated into HP-PLGA-MS using a simple immersion method. The release rate of BMP2 could be controlled by the amount of Col1. DEX and BMP2 showed a sustained release profile. These results showed that the HP-PLGA-MS could be fabricated successfully using sucrose and showed great potential as a controlled dual drug delivery system. © 2016 The Korean Society of Industrial and Engineering Chemistry.

Park J.H.,Ajou University | Kang H.J.,Ajou University | Kwon D.Y.,Ajou University | Lee B.K.,Ajou University | And 5 more authors.
Journal of Materials Chemistry B | Year: 2015

To develop an appropriate drug carrier for drug delivery systems, we prepared random poly(lactide-co-glycolide-co-ε-caprolactone) (PLGC) copolymers in comparison to commercial poly(lactic acid-co-glycolic acid) (PLGA) grades. The molecular weights of PLGC copolymers varied from 20k to 90k g mol-1 in the total polyester segments, when poly-l-lactic acid (PLLA), polyglycolic acid (PGA), and polycaprolactone (PCL) compositions were kept constant. The lengths of PLGC copolymers varied from 10:10:80 to 40:40:20 in the PLLA:PGA:PCL segments, when the molecular weights of the total polyester segments were kept constant. The crystalline properties of the PLGA copolymers can be changed to amorphous by the incorporation of PCL segments. In vitro and in vivo degradation behavior can be easily tuned from a few days to a few weeks by changing the chemical composition of the PLGC copolymers. The in vivo inflammation associated with the PLGC implants was less pronounced than that associated with PLGA. In this study, as drug delivery carriers for locally implantable paclitaxel (Ptx) dosages, Ptx-loaded PLGC and PLGA films showed in vitro and in vivo Ptx release for 35 days. The orders of Ptx release showed profiles similar to those of in vitro and in vivo degradation of PLGC. Using near-infrared (NIR) fluorescence imaging, we confirmed the sustained release of NIR over an extended period from IR-780-loaded PLGC and PLGA implanted in live animals. In conclusion, we confirmed that compared to PLGA, PLGC effectively acts as a drug carrier for drug delivery systems. © The Royal Society of Chemistry 2015.

Kim J.-T.,Anyang University, South Korea | Lee D.Y.,Anyang University, South Korea | Kim E.-J.,Health Science University | Jang J.-W.,Cellumed Co. | Cho N.-I.,Sun Moon University
Tissue Engineering and Regenerative Medicine | Year: 2014

Hyaluronic acid hydrogels (HAHs) were synthesized by immersing the HA microbeads crosslinked with divinyl sulfone in phosphate buffered saline solution to assess the responses of tissues to the implant by means of the subchronic systemic toxicity and the intradermal implant test. The HAHs, prepared by the microbeads with an average diameter of 140 μm and a swelling rate of 800 to 1200%, exhibited a porous network channeled with 10 μm pores. The HAHs retained their space and structure by maintaining over 95% of the initial volume 12 weeks after injection to a rabbit. The histological analysis indicated that an acute inflammation, occurred in the rabbit 4 weeks after injection, was alleviated dramatically after 8 weeks. No capsule was formed. The HAHs had no subchronic systemic toxicity under the condition of this study and were considered non-irritant. The implants were excellent in biological synthesis and transplantation as evidenced by non-capsule reaction and disappearance of inflammatory cells. It can be concluded that the implants of HAHs are clinically safe and effective.

Kwon D.Y.,Ajou University | Tai G.Z.,Ajou University | Park J.H.,Ajou University | Lee B.K.,Ajou University | And 6 more authors.
Journal of Polymer Research | Year: 2014

To compare methoxy poly (ethylene glycol) (MPEG)-b-poly (ε-caprolactone) (M7C10L0) and MPEG-bpoly (L-lactide) (M7C0L10), we performed block copolymerization of ε-caprolactone (CL) and L-lactide (LA) to synthesize block copolymers composed of MPEG-b-poly (ε- caprolactone-co-L-lactide) (MxCyLz). The obtained MxCyLz, M7C10L0, and M7C0L10 had molecular weights close to the theoretical values calculated from the CL and/or LA to MPEG molar ratios and exhibited monomodal gel permeation chromatography (GPC) curves. The micellar characterization of MxCyLz block copolymers in an aqueous phase was carried out by using NMR, dynamic light scattering (DLS), and fluorescence techniques. The diameters of micelles, measured by DLS, were 30-370 nm. The critical micelle concentration (CMC) and partition equilibrium constant (Kv) depended on the block lengths and compositions of block copolymers. The degradation of theMxCyLz block copolymers mainly depends on both the length of hydrophilic MPEG segments and the proportion of the CL and LA in the hydrophobic segments present in their structure. We confirmed that MxCyLz block copolymers formed biodegradable micelles suitable for biomedical applications. © Springer Science+Business Media Dordrecht 2014.

Nam H.,University of Seoul | Kim H.,University of Seoul | Park Y.,Hongik University | Sung J.H.,Hongik University | And 4 more authors.
Science of Advanced Materials | Year: 2014

Transdermal delivery has been widely recognized as a powerful method for drug delivery that can overcome shortcomings of oral administration. Injection with hypodermic needles, however, have problems including pain, bleeding, need of special training to use and high risk of infection. To overcome those limitations, microneedles are widely studied for the delivery of a variety of therapeutics into body. Here, we introduce DNA-coated microneedles that can be used as a tool for gene therapy. Therapeutic DNA is first amplified by rolling circle amplification from template circular DNA to deliver multiple copies of them. Microneedles with two monomers of poly(ethylene glycol) diacrylate and acrylamide that are known to be biocompatible are then coated with amplified DNA strands by electrostatic interactions. Our DNA-coated microneedles can highly localize the delivery site while minimizing pain. We expect that this approach will help turning biological potential into medical reality. © 2014 by American Scientific Publishers.

Discover hidden collaborations