• Polymer(Korea)
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• v.24 no.5
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• pp.728-735
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• 2000

Fentanyl-loaded biodegradable poly(L-lactide-co-glycolide) (75 : 25 by mole ratio of lactide to glycolide, PLGA) microspheres (MSs) were prepared to study the possibility for long-acting local anesthesia. We developed the fentanyl base (FB, slightly water-soluble)-loaded PLGA MSs by means of conventional O/W solvent evaporation method. The size of MSs was in the range of 10~150 ${\mu}{\textrm}{m}$. The morphology of MSs was characterized by SEM, and the in vitro release amounts of FB were analyzed by HPLC. The lowest porous cross-sectional morphology and the highest encapsulation efficiency were obtained by using gelatin as an emulsifier. The influences of several preparation parameters, such as emulsifier types, molecular weights and concentrations of PLGA, and initial drug loading amount, etc., have been observed in the release patterns of FB. The release of FB in vitro was more prolonged over 25 days, with close to zero-order pattern by controlling the preparation parameters. We also investigated the physicochemical properties of FB-loaded PLGA MSs by X-ray diffraction and differential scanning calorimeter.

• Journal of Dairy Science and Biotechnology
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• v.23 no.1
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• pp.9-17
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• 2005

Nanotechnology has penetrated into the various branches of research and development and it is particularly of benefit to the particle size engineering. It has been widely known that the particle size of an active pharmaceutical ingredient (API) is critical in determining the bioavailability and processability of pharmaceutical formulation. However, the window of appropriate particle size has been limited mainly due to related processing difficulties. The windows have been widened by the recent development of nanotechnologies, resulting in diversified drug delivery systems. The impact of this development is far more fundamental than what can be expected from conventional particle size engineering. It is the case that the preparation and use of nanoparticles will soon be a common task in the particle engineering step of pharmaceutical unit operations. In this chapter, the basic principles of variouspreparation techniques will be discussed in detail. Regardless of processing details, the preparation methods of pharmaceutical nanoparticles mainly concern how to deal with the extra energy related with particle size. Depending on the ways of treating the e103 energy, preparation methods can be classified into two major classes, i.e.. thermodynamic and kinetic approaches. The recent progresses have shown the possibilities of much more complex combinations of different approaches and the use of new types of energy and nanostructures.

• The Journal of Korean Medicine
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• v.38 no.3
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• pp.124-142
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• 2017

Objectives: This study aimed to learn what should be considered in [Guideline of Clinical Trial with Herbal Medicinal Product for Gastric Cancer)] by analyzing the existing guidelines and clinical trials. Methods: The development committee searched guidelines for herbal medicinal product or gastric cancer developed already. Then, clinical trials for gastric cancer using herbal medicine were searched. The searched trials were analyzed in terms of inclusion and exclusion of participants, intervention, comparator, outcomes and trial design. Then, we compared the results of analysis with the regulations and guidelines of Ministry of Food and Drug Safety to suggest the issue that we will have to consider when making the [Guideline of Clinical Trial with Herbal Medicinal Product for Gastric Cancer]. Results: As a result, few guidelines for anti-tumor agent and clinical trial with herbal medicinal product were searched in the national institution homepage. In addition, 10 articles were searched by using the combination following search term; 'stomach neoplasm', 'herbal medicine', 'Medicine, Korean traditional', 'Medicine, Chinese Traditional', 'TCM', 'TKM', 'trial'. Most trials included gastric cancer participants with medical history of operation. The type of intervention was various such as decoction, granules, and fluid of intravenous injection. Comparators were diverse such as placebo, conventional treatment including chemotherapy and nutritional supplement. The most frequently used outcome for efficacy was quality of life. Besides, the symptom score, tumor response, and survival rate were used. Safety was investigated by recording adverse events. Conclusion: We found out some issue by reviewing the existing guidelines and comparing it with clinical trials for gastric cancer and herbal medicinal products. These results will be utilized for developing [Guideline of Clinical Trial with Herbal Medicinal Product for Gastric Cancer].

• Journal of Pharmaceutical Investigation
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• v.41 no.3
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• pp.125-142
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• 2011

Solid dispersion, defined as the dispersion of one or more active ingredient in a carrier or matrix at solid state, is an efficient strategy for improving dissolution of poorly water-soluble drugs for enhancement of their bioavailability. Compared to other conventional formulations such as tablets or capsules, solid dispersion which can be prepared by various methods has many advantages. However, despite numerous studies which have been carried out, limitations for commercializing these products remain to be solved. For example, during the manufacturing process or storage, amorphous form of solid dispersion can be converted into crystalline form. That is, the dissolution rate of solid dispersion would continuously decrease during storage, resulting in a product of no value. To resolve these problems, studies have been conducted on the effects of excipients. In fact, modification of the solid dispersions to overcome these disadvantages has progressed from the first generation to the recent third generation products. In this review, an overview on solid dispersions in general will be given with emphasis on the various manufacturing processes which include the use of polymers and on the stabilization strategies which include methods to prevent crystallization.

• Journal of Ginseng Research
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• v.39 no.2
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• pp.155-161
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• 2015

Background: Korean ginseng is an ethnopharmacologically valuable herbal plant with various biological properties including anticancer, antiatherosclerosis, antidiabetic, and anti-inflammatory activities. Since there is currently no drug or therapeutic remedy derived from Korean ginseng, we developed a ginsenoside-enriched fraction (AP-SF) for prevention of various inflammatory symptoms. Methods: The anti-inflammatory efficacy of AP-SF was tested under in vitro inflammatory conditions including nitric oxide (NO) production and inflammatory gene expression. The molecular events of inflammatory responses were explored by immunoblot analysis. Results: AP-SF led to a significant suppression of NO production compared with a conventional Korean ginseng saponin fraction, induced by both lipopolysaccharide and zymosan A. Interestingly, AP-SF strongly downregulated the mRNA levels of genes for inducible NO synthase, tumor necrosis factor-${\alpha}$, and cyclooxygenase) without affecting cell viability. In agreement with these observations, AP-SF blocked the nuclear translocation of c-Jun at 2 h and also reduced phosphorylation of p38, c-Jun N-terminal kinase, and TAK-1, all of which are important for c-Jun translocation. Conclusion: Our results suggest that AP-SF inhibits activation of c-Jun-dependent inflammatory events. Thus, AP-SF may be useful as a novel anti-inflammatory remedy.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.597-601
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• 2013

In this study, we present simple microfluidic approach for the synthesis of monodisperse microcapsules by using droplet-based system. We generate double emulsion through single step in the microfluidic device having single junction while conventional approaches are limited in surface treatment for the generation of double emulsion. First, we have injected disperse fluid containing FC-77 oil and photocurable ethoxylated trimethylolpropane triacrylate (ETPTA) and water containing 3 wt% poly(vinyl alcohol) (PVA) as continuous phase into microfluidic device. Under the condition, we easily generate double emulsion with high monodispersity by using flow focusing. The double emulsion droplets are transformed into microcapsules under the UV irradiation via photopolymerization. In addition, we control thickness of double emulsion's shell by controlling flow rate of ETPTA. We also show that the size of double emulsions can be controlled by manipulation of flow rate of continuous phase. Furthermore, we synthesize microcapsules encapsulating various materials for the application of drug delivery systems.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.472-477
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• 2015

This study presents modified microfluidic picoinjector combined Faraday moat with silver nanoparticle electrode to increase electrical efficiency and fabrication yield. We perform simple dropping procedure of silver nanoparticles near the picoinjection channel, which solve complicate fabrication process of electrode deposition onto the microfluidic picoinjector. Based on this approach, the microfluidic picoinjector can be reliably operated at 180 V while conventional Faraday moat usually have performed above 260 V. Thus, we can reduce the operation voltage and increase safety. Furthermore, the microfluidic picoinjector is able to precisely control injection volume from 7.5 pL to 27.5 pL. We believe that the microfluidic picoinjector will be useful platform for microchemical reaction, biological assay, drug screening, cell culture device, and toxicology.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.54-59
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• 2013

Micro shock tubes are now-a-days used for a variety engineering applications such as in the field of aerospace, combustion technology and drug delivery systems. But the flow characteristics of micro shock tube will be different from that of well established conventional macro shock tube under the influence of very low Reynolds number and high Knudsen number formed due to smaller diameter. In present study, experimental studies were carried out to a closed end (downstream) Micro Shock Tube with two different diameters were investigated to understand the flow characteristics. Pressure values were measured at different locations inside the driver and driven section. The results obtained show that with the increase in diameter the shock propagation velocity increases as well as the effect of reflected shock wave will be more significant under the same diaphragm rupture pressure.

• YAKHAK HOEJI
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• v.49 no.1
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• pp.38-43
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• 2005

The occurrence of resistance to chemotherapeutic drugs is a major problem for successful cancer treatment. This resistant phenotype of cancer cell frequently reveals a broad spectrum to structurally and/or functionally unrelated anticancer drugs, termed multidrug resistance (MDR). Overexpression of P-glycoprotein (P-gp), a transmembrane drug efflux pump, is a major mechanism of MDR. Accordingly, considerable effort has been directed towards to development of compounds that inhibit P-gp, reverse the MDR phenotype and sensitize cancer cells to conventional chemotherapy without undesired toxicological effects. In an effort to search for novel MDR reversal agent, we tested the cytotoxicity of paclitaxel, a well-known substrate of P-gp, against P-gp-expressing HCT15 and HCT15/CL02 human colorectal cancer cells in the presence or absence of benzotriazepin analogues, as well as against P-gp-negative A549 human non-small cell lung and SK-OV-3 human ovarian cancer cells in vitro. Among the compounds tested, the agents that have phenyl amide moiety at 3 position remarkably increased the cytotoxicity of paclitaxel against P-gp-expressing cancer cells, but not against P-gp-negative cancer cells. BTZ-15 and BTZ-16 at $4\;{\mu}M$ revealed similar MDR reversal activity to $10\;{\mu}M$ verapamil, a well-known MDR reversal agent.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.223-228
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• 2016

In this study, we described a simple and facile method to generate uniform microwells poly(dimethyl siloxane) (PDMS) microstamps through micro-molding for efficient, rapid and reliable cell patterning of adipocyte differentiation. In contrast to the conventional methods, the microstamp technologies are low expensive, non-toxic, and using a small amount of solution. Recently, Orlistat known as tetrahydrolipstatin is a prescription drug designed to treat obesity which is used to aid in weight loss and help to reduce overweight obesity. Here, 3T3-L1 cells were treated under various concentration manners of Orlistat $0.2{\mu}M{\sim}5.0{\mu}M$. and it was confirmed maximum 26.5% inhibition activity compared to control. Thus, we elucidated this platform can be used for the real-time analyzing of cell proliferation, adipocyte differentiation for evaluation of anti-obesity agents on cell chip. Furthermore, we except that this platform technology designed here might be readily be expanded to discover a wider variety of anti-obesity agents.