Authors: Chang Rae Lee, Moon Suk Kim, Hai Bang Lee, Han Ku Lee, John M. Rhee, Gil Son Khang
Abstract: We developed the successive roller type of microneedle system without pain to improve
the permeation of drug through the skin barrier. The permeation rates of FITC-ovalbumin (OVA,
MW: 45,000g/mole), FITC-insulin (MW: 5,733 g/mole) and FITC-bufexamac (MW: 227.37
g/mole) as model drugs were determined by modified Franz diffusion cells using the microneedle
device with four times treatment. The average penetration fluxes of FITC- OVA, FITC-insulin and
FITC-bufexamac were steeply increased from 13.4 to 83.3, 10.1 to 110.6 and 11.9 to 242.6
pmol/cm2 with treatment for 12 hrs, respectively. The lower the molecular weight of the drugs, the
more the permeation flux investigated. In conclusion, we confirmed the possibility of the
application for transdermal delivery of the larger molecular drugs as protein using the designed
microneedle treatment device.
945
Authors: Gil Son Khang, Jae Chan Yang, Jong Tae Ko, Jung Soo Park, Moon Suk Kim, John M. Rhee, Hai Bang Lee
541
Authors: Jong Tae Ko, Hyung Joon Jung, Jong Hyon Mo, Jae Song Cho, Soon Hong Yuk, Hyung Shik Shin, Moon Suk Kim, John M. Rhee, Hai Bang Lee, Gil Son Khang
Abstract: The double-layered microspheres play an important role in controlling drug delivery for
pharmaceutical application, because of the low initial burst compared with single-layered spheres
and targetable delivery to specific organ. But it has drawback in loading drug and controlling size.
In this study, we developed double-layered spheres using relatively simple oil-in-water (O/W)
solvent evaporation method using bovine serum albumin (BSA) as water-soluble protein and
poly(D,L-lactide-co-glycolide) (PLGA). BSA/PLGA double-layered microspheres were fabricated
using O/W solvent evaporation method and investigated the specific character of double-layered
microspheres according to the kind of surfactants. In SEM observation, double layered microsphere
had spherical shape and smooth surface without pores. And the double layered microsphere using
O/W solvent evaporation method was transparency because of slow evaporation of solvent. In
fluorescent observation, we observed the fluorescent core in the double-walled spheres composed of
FITC-BSA and PLGA using fluorescent observation. In the case of polyvinylalcohol as emulsifier,
the yield was better than gelatin. As decreased concentration of PLGA, the size of double-layered
microspheres deceased.
513
Authors: Soo Young Lee, Young Ho Cho, Ju Yong Youn, Moon Suk Kim, Bong Lee, Gil Son Khang, Hai Bang Lee
Abstract: To develop osmotic granule with semi-permeable membranes, we prepared the semipermeable
membranes with different pore forming agent by using solvent casting method. The
membrane was consisted of cellulose acetate, Eudragit® RS, hydroxypropylcellulose (HPC), and
triethylcitrate (TEC) in the presence of PEG200, PEG1, 000, or dibutylsebacate(DBS) as a pore
forming agent. The produced membranes were white and elastic and exhibited soft property on
touch. The release amount of pore forming agent from membrane with different pore forming agent
was measured in water dissolution media and the order was PEG200 > PEG1, 000 > DBS. The
formation of pore in membrane was observed by morphological SEM image after dissolution. The
pore formation and porosity of membrane depended on water solubility of pore forming agent. We
confirmed that pores in porous semi-permeable membrane could be controlled by the pore forming
agent.
485
Authors: Mi Hee Cho, Hoon Hyun, Yu Na Shin, Jung Won Lee, Min Suk Lee, Hyun Hee Ahn, Moon Suk Kim, Bong Lee, Gil Son Ghang, Hai Bang Lee
Abstract: Methoxy poly(ethylene glycol) (MPEG)-b-poly(ε-caprolactone) (PCL) diblock
copolymer was synthesized by ring-opening of ε-caprolactone (ε-CL) in the presence of a monomer
activator with the terminal alcohol of MPEG as an initiator. The temperature sensitive behavior of
the prepared MPEG-PCL diblock copolymer solution was examined. The polymer solution formed
translucent sol at the room temperature. As the temperature increased from room temperature, the
sol became gel, indicating that the diblock copolymer solution at room temperature can form gel at
body temperature. Brain-derived neurotrophic factor (BDNF) loaded MPEG-PCL diblock
copolymer solution and Pluronic solution for comparison were prepared to examine the release
behavior of BDNF. Pluronic gel exhibited nearly complete release of BDNF even at 2 day, while
the release of BDNF in MPEG-PCL gel showed the prolonged release profile for 21 days. In this
study, we confirmed that thermosensitive MPEG-PCL diblock copolymer in this work could utilize
as a potential carrier of BDNF.
473
Authors: Yu Na Shin, Mi Hee Cho, Hyun Hee Ahn, Moon Suk Kim, Gil Son Ghang, Hai Bang Lee
Abstract: The goal of this study was to investigate release tendency of brain-derived neurotrophic
factor (BDNF) from poly(L-lactide-co-glycolide) (PLGA) and small intestine submucosa (SIS)
scaffold prepared by ice-leaching method. A porous scaffold consisting of PLGA and SIS as carrier
of BDNF has been prepared in the presence of ice particle. SEM image of the PLGA/SIS scaffold
showed an interconnected pore structure. The release behavior of BDNF loaded PLGA/SIS scaffold
was examined for 4 weeks period at phosphate buffered saline (PBS, pH 7.4) at 37 oC. The
sustained release of BDNF over 4 weeks was observed from the PLGA/SIS scaffold. These results
indicate that the sustained release of BDNF from PLGA/SIS scaffold can be very useful for
application in the tissue engineering.
413
Authors: Soon Hee Kim, Bang Sil Choi, Youn Kyung Ko, Hyun Jung Ha, Sun Jung Yoon, John M. Rhee, Moon Suk Kim, Hai Bang Lee, Gil Son Khang
Abstract: In order to application for the tissue engineered intervertebral disc (IVD), we designed
the synthetic/natural hybrid scaffolds with poly(lactide-co-glycolide) (PLGA) and small intestine
submucosa (SIS). SIS has been widely used as a biomaterial because SIS consists of various
collagens and cytokines. SIS, however, possesses disadvantages such as their weak mechanical
properties and uncontrolled degradation. Novel composite scaffolds of PLGA/SIS were
manufactured by simple immersion method of PLGA scaffolds in SIS solution under vacuum. Then
SIS was crosslinked. Also, PLGA scaffolds and SIS sponges were manufactured by solvent
casting/salt leaching and freeze-dried methods, respectively. We evaluated pore structure, porosity,
water absorption ability and cell viability of three types of scaffolds for the application of IVD.
389
Authors: Yu Han Kim, Mi Hee Cho, In Bum Song, Hoon Hyun, Jung Won Lee, Moon Suk Kim, Seog Jin Seo, Ke Won Kang, Gil Son Khang, Sung Yun Yang, Hai Bang Lee
Abstract: In this study, we developed an injectable carrier for demineralized bone matrix (DBM)
which consists of chitosan and glycerol phosphate (GP). The phase transition behaviors of chitosan
and GP solution characterized as a function of temperature. The chitosan and GP solutions were
shown to form a sol at room temperature, and the chitosan solution with 10-20 wt% concentrations
were found to undergo sol-to-gel phase transitions as the temperature was increased. In situ gel
forming implant in vivo was successfully fabricated by simple subcutaneous injection of chitosan
and GP solutions with demineralized bone matrix (DBM). von Kossa images of the gel implant
formed from solution with DBM revealed the presence of mineral deposits.
177
Authors: Youn Kyung Ko, Soon Hee Kim, Hyun Jung Ha, Sun Jung Yoon, John M. Rhee, Moon Suk Kim, Hai Bang Lee, Gil Son Khang
Abstract: Recently, it has been studied tissue engineered technique as novel approaches for
treatment of the degenerative intervertebral disc (IVD). We designed the hybrid type of IVD
mimicked scaffolds with poly(lactide-co-glycolide) (PLGA) and methoxypoly(ethyleneglycol)-
poly(-caprolactone) (MPEG-PCL) diblock copolymers in order to application for the tissue
engineered IVD. The MPEG-PCL solutions formed a gel-to-sol phase transitions as the temperature
was increasesd. MPEG-PCL diblock copolymers were prepared by ring opening polymerization,
and then nucleus pulposus (NP) cell was impregnated. Also, in order to restore annulus fibrosus
(AF), we fabricated PLGA scaffold by solvent casting/salt leaching method. We confirmed disc cell
function in manufactured scaffold through MTT assay in vitro and gross morphology and special
staining in vivo for the possibility of the application of tissue engineering techniques.
173
Authors: Sun Jung Yoon, Ki Suk Park, Bang Sil Choi, Gil Son Khang, Moon Suk Kim, John M. Rhee, Hai Bang Lee
Abstract: This study was designed to investigate the influence of demineralized bone particles
(DBP)/PLGA hybrid scaffold on angiogenesis and osteogenesis in a calvarial defect model.
DBP/PLGA scaffolds were manufactured by solvent casting/salt leaching method, and each scaffold
contained 0, 10, 20, 40, and 80 wt% DBP of PLGA, respectively. A total of 34 rats were operated
and bicortical holes were placed on their calvaria. The defects were filled with different ratio
DBP/PLGA scaffolds. After 3, 7, 14, and 28 days, specimens were taken and, histologic,
immunohistologic and RT-PCR analyses were carried out concerning number of vessels and density
of regenerated bone, and angiogenic activation. On days 7, in all experimental groups, bone
formation occurred in a direction from defected margin of calvarium to center of implanted scaffold
and new vessel formation took place in front of the osteogenic regeneration front. We found that the
20 and 40 wt% DBP/PLGA scaffold was superior in its ability to regenerate new bone, induced
more intensive formation of microvasculature and expressed in a higher level of osteocalcin mRNA
than other groups.
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