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The Effect of Solvents on Solid Dispersion of Ipriflavone with Polyvinylpyrrolidone In Vivo
Gilson Khang,Je Kyo Jeong,Yong San Ahn,Byung Kwan Moon,Myung Kyu Choi,John M. Rhee,Hai Bang Lee 한국약제학회 2005 Journal of Pharmaceutical Investigation Vol.35 No.1
Ipriflavone is a synthetic flavonoid derivate that improves osteoblast cell activity inhibiting bone resorption. In order to improve the bioavailability, solid dispersions of ipriflavone with PVP (poly-N- vinylpyrrolidone, MW=40,000 g/ mole) were prepared by a spray-drying method. During the manufacturing of solid dispersion, various solvents [ethanol (EtOH), acetonitrile, methylene chloride and cosolvent-EtOH:acetone=1:1] were used to dissolve the ipriflavone and PVP. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were used to evaluate the physicochemical interaction between ipriflavone and PVP. Particle size, crystallinity and the area of the endotherm (∆H) of solid dispersed ipriflavone using the acetonitrile as solvent were much smaller than those of the other preparation types. Bioavailability of ipriflavone in vivo was changed by solvents. When considering the result of in vivo test, solid dispersion of ipriflavone using the acetonitrile as solvent showed the best choice.
Khang, Gilson,Rhee, John M.,Shin, Philkyung,Kim, In Young,Lee, Bong,Lee, Sang Jin,Lee, Young Moo,Lee, Hai Bang,Lee, Ilwoo The Polymer Society of Korea 2002 Macromolecular Research Vol.10 No.3
In order to endow with new bioactive functionality from small intestine submucosa (SIS) powder as natural source to poly (L-lactide) (PLA) and poly (lactide-co-glycolide) (PLGA) synthetic biodegradable polymer, porous SIS/PLA and SIS/PLGA as natural/synthetic composite scaffolds were prepared by means of the solvent casting/salt leaching methods for the possibility of the application of tissue engineered bone and cartilage. A uniform distribution of good interconnected pores from the surface to core region was observed the pore size of 40~500 ${\mu}{\textrm}{m}$ independent with SIS amount using the solvent casting/salt leaching method. Porosities, specific pore areas as well as pore size distribution also were almost same. After the fabrication of SIS/PLA hybrid scaffolds, the wetting properties was greatly enhanced resulting in more uniform cell seeding and distribution. Five groups as PGA non-woven mesh without glutaraldehyde (GA) treatment, PLA scaffold without or with GA treatment, and SIS/PLA (Code No.3 ; 1 : 12 of salt content, (0.4 : 1 of SIS content, and 144 ${\mu}{\textrm}{m}$ of median pore size) without or with GA treatment were implanted into the back of nude mouse to observe the effect of SIS on the induction of cells proliferation by hematoxylin and eosin, and von Kossa staining for 8 weeks. It was observed that the effect of SIS/PLA scaffolds with GA treatment on bone induction are stronger than PLA scaffolds, that is to say, in the order of PLA/SIS scaffolds with GA treatment > PLA/SIS scaffolds without GA treatment > PGA nonwoven > PLA scaffolds only with GA treatment = PLA scaffolds only without GA treatment for the osteoinduction activity. The possible explanations are (1) many kinds of secreted, circulating, and extracellular matrix-bound growth factors from SIS to significantly affect critical processes of tissue development and differentiation, (2) the exposure of SIS to GA resulted in significantly calcification, and (3) peri-implant fibrosis due to covalent bonding between collagen molecule by crosslinking reaction. In conclusion, it seems that SIS plays an important role for bone induction in SIS/PLA scaffolds for the application of tissue engineering area.
Neurogenesis of bone marrow-derived mesenchymal stem cells onto β-mercaptoethanol-loaded PLGA film.
Khang, Gilson,Kim, Hye Lin,Hong, Minsung,Lee, Dongwon Springer 2012 Cell and tissue research Vol.347 No.3
<P>Bone marrow-derived mesenchymal stem cells (BMSCs) are of particular interest in the field of tissue engineering because of their potential to differentiate into osteoblasts, chondrocytes, and neuronal cells. In order to promote the differentiation of BMSCs into specific cell types, appropriate scaffold biomaterials and bioactive molecules that can support the differentiation of BMSCs into specific cell types are needed. We hypothesized that β-mercaptoethanol (BME), which has been reported to induce the differentiation of BMSCs into neural-like cells, promotes BMSCs to differentiate into neural-like cells when BME is added to polymeric scaffolds containing the BMSCs. We fabricated biocompatible film shaped scaffolds composed of poly(lacti-co-glycolic) acid (PLGA) and various concentrations of BME to confirm that BME-promoted differentiation of BMSCs is concentration-dependent. Cell proliferation increased as the BME concentration in the films increased at the early stage, and the proliferation rate remained similar on the PLGA films for 3?weeks following the BMSC seeding. The expression of neuronal markers in differentiated BMSCs was assessed by RT-PCR. At 2- and 3-week time-points, mRNA expression of neurofilament and neuron specific enolase was significantly increased in PLGA/BME films containing 400?μM BME compared to PLGA films. Thus, we have identified BMSC-seeded PLGA/BME films with 200?μM and 400?μM BME as potentially useful candidates for neural tissue engineering applications by promoting BMSC proliferation and differentiation towards neural-like cells.</P>
Yifeng Ling,Gilson Lomboy,Zhi Ge,Kejin Wang Techno-Press 2023 Structural monitoring and maintenance Vol.10 No.2
High performance concrete (HPC) has been extensively used in thin overlay for repair purpose due to its excellent strength and durability. This paper presents an experiment, where the sensor-instrumented HPC overlays have been followed by dynamic strain and moisture content monitoring for 1 year, under normal traffic. The vibrating wire and soil moisture sensors were embedded in overlay before construction. Four given HPC mixes (2 original mixes and their shrinkage-modified mixes) were used for overlays to contrast the strain and moisture results. A calibration method to accurately measure the moisture content for a given concrete mixture using soil moisture sensor was established. The monitoring results indicated that the modified mixes performed much better than the original mixes in shrinkage cracking control. Weather condition and concrete maturity at early age greatly affected the strain in concrete. The strain in HPC overlay was primarily in longitudinal direction, leading to transverse cracks. Additionally, the most moisture loss in concrete occurred at early age. Its rate was very dependent on weather. After one year, cracking survey was carried out by vision to verify the strain direction and no cracks observed in shrinkage modified mixes.
강복기,강길선,김종민,정상영,이해방,조선행 한국약제학회 2003 Journal of Pharmaceutical Investigation Vol.33 No.3
Melatonin (MT) is an indole amide pineal hormone. It has not only very short half-life but also pH-sensitive property. The sustained release dosage form which delivers M in a circadian fashion over 8 h is clinical value. The purpose of this study is to prepare sugar beads using multiple coating methods and enteric-coated in a sustained release to evaluate in vitro release characteristics in simulated gastric and intestinal fluids. The Eudragit^(?) as a polymer, sustained release membrance, and triethylcitrate (TEC) as a plasticizer were used. Multi-coated melatonin delivery system was composed of sugar, various excipients, Eudragit^(?) and enteric materials (e.g. hydorxy propyl methyl celluslose phthalate, HPMCP), and prepared by fluid bed coater. The dissolution test was carried out using the basket method at a stirring speed of 100 rpm at 37℃ in simulated gastric (pH 1.2) and intestinal fluid (pH 7.4). The released amount of MT was determined by High performance liquid chromatography method. The morphologies of surface and cross section of multi-coated beads were observed by scanning electron microscope. Size of multi-coated sugar beads was ranged over 1000∼1300 μm. The release rate of MT from coated beads was limited in simulated gastric fluid (pH 1.2), but it was sustained in intestinal fluid (pH 7.4) during 3∼8 hours. The MT beads may provide small-intestine-targeted device for oral delivery. Studies an animal and relative experiment are in process.