• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.647-659
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• 2008

Colloids are a heterogeneous system in which particles of a few nanometers to hundreds micrometers in size are finely dispersed in liquid medium, but show homogeneous properties in macroscopic scale. They have attracted much attention not only as model systems of natural atomic and molecular self-assembled structures but also as novel structural materials of practical applications in a wide range of areas. In particular, recent advances in colloidal science have focused on nano-bio materials and devices which are essential for drug discovery and delivery, diagnostics and biomedical applications. In this review, first we introduce nano-bio colloidal systems and surface modification of colloidal particles which creates various functional groups. Then, various methods of fabrication of colloidal particles using holographic lithography, microfluidics and virus templates are discussed in detail. Finally, various applications of colloids in metal inks, three-dimensional photonic crystals and two-dimensional nanopatterns are also reviewed as representative potential applications.

• Journal of Pharmaceutical Investigation
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• v.40 no.4
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• pp.255-261
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• 2010

Pluronic as pharmaceutical excipients are listed in the US and British Pharmacopoeia. In particular, Pluronics exist as different compositions and display abundant phases as self-assembling into polymeric micelles with various morphologies depending on the aqueous solvent quality, the composition of structure, and hydrophilic-lipophilic balance (HLB). Pluronics were also known as a P-gp modulator, which was exploited as a reversal molecule of multi-drug resistant (MDR) cancers. We selected a lamella forming Pluronic L92 which has high hydrophobicity and relatively long PEO block among L series of Pluronics. The dispersion of L92 showed great size particles and low stability. To increase the stability and to decrease the particle size, secondary Pluronics (F68, F88, F98, F127, P85, P105, and P123) with relatively long PEO chain were added into 0.1 wt% Pluronic L92 dispersion. The stability of binary systems was increased due to incorporated long PEO chain. Their particle sizes slightly decreased to over 200~400 nm and their solubilization capacity of binary systems didn't change except Pluronic L92/P123 mixtures. The L92/P123 systems showed ca. 100 nm sizes and lowest turbidity among the all systems. The solubilization capacity of 0.1 wt% L92/0.1 wt% P123 was slightly increased compared to 0.1 wt% L92 mono system and other binary systems. These nano-sized binary systems may have potential as alternative drug delivery systems with simple preparation method and overcome the drawbacks of mono systems such as low stability and loading capacity.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.712-719
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• 2006

In this study, we prepared core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer with varying graft ratio of PLGA. The synthesis of the DexLG copolymer was confirmed by $^1H$ nuclear magnetic resonance (NMR) spectroscopy. The DexLG copolymer was able to form nanoparticles in water by self-aggregating process, and their particle size was around $50\;nm{\sim}300\;nm$ according to the graft ratio of PLGA. Morphological observations using a transmission electron microscope (TEM) showed that the nanoparticles of the DexLG copolymer have uniformly spherical shapes. From fluorescence probe study using pyrene as a hydrophobic probe, critical association concentration (CAC) values determined from the fluorescence excitation spectra were increased as increase of DS of PLGA. $^1H-NMR$ spectroscopy using $D_2O$ and DMSO approved that DexLG nanoparticles have core-shell structure, i.e. hydrophobic block PLGA consisted inner-core as a drug-incorporating domain and dextran consisted as a hydrated outershell. Drug release rate from DexLG nano-particles became faster in the presence of dextranase in spite of the release rate not being significantly changed at high graft ratio of PLGA. Core-shell type nanoparticles of DexLG copolymer can be used as a colonic drug carrier. In conclusion, size, morphology, and molecular structure of DexLG nanoparticles are available to consider as an oral drug targeting nanoparticles.

• Korean Journal of Materials Research
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• v.20 no.3
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• pp.132-136
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• 2010

This study examined the biostability and drug delivery efficiency of g-$Fe_2O_3$ magnetic nanoparticles (GMNs) by cytotoxicity tests using various tumor cell lines and normal cell lines. The GMNs, approximately 20 nm in diameter, were prepared using a chemical coprecipitation technique, and coated with two surfactants to obtain a water-based product. The particle size of the GMNs loaded on hangamdan drugs (HGMNs) measured 20-50 nm in diameter. The characteristics of the particles were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-TEM) and Raman spectrometer. The Raman spectrum of the GMNs showed three broad bands at 274, 612 and $771\;cm^1$. A 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay showed that the GMNs were non-toxic against human brain cancer cells (SH-SY5Y, T98), human cervical cancer cells (Hela, Siha), human liver cancer cells (HepG2), breast cancer cells (MCF-7), colon cancer cells (CaCO2), human neural stem cells (F3), adult mencenchymal stem cells (B10), human kidney stem cells (HEK293 cell), human prostate cancer (Du 145, PC3) and normal human fibroblasts (HS 68) tested. However, HGMNs were cytotoxic at 69.99% against the DU145 prostate cancer cell, and at 34.37% in the Hela cell. These results indicate that the GMNs were biostable and the HGMNs served as effective drug delivery vehicles.

• CELLMED
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• v.11 no.1
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• pp.6.1-6.7
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• 2021

In situ gelling devices, as they enter the body, are dosage forms in the shape of the sol but turn into gel types under physiological circumstances. Transition from sol to gel is contingent on one or a mixture of diverse stimuli, such as transition of pH control of temperature, irradiation by UV, by the occurrence of certain ions or molecules. Such characteristic features may be commonly employed in drug delivery systems for the production of bioactive molecules for continuous delivery vehicles. The technique of in situ gelling has been shown to be impactful in enhancing the potency of local or systemic drugs supplied by non-parenteral pathways, increasing their period of residence at the absorption site. Formulation efficacy is further improved with the use of mucoadhesive agents or the use of polymers with both in situ gelling properties and the ability to bind with the mucosa/mucus. The most popular and common approach in recent years has provided by the use of polymers with different in situ gelation mechanisms for synergistic action between polymers in the same formulation. In situ gelling medicine systems in recent decades have received considerable interest. Until administration, it is in a sol-zone and is able to form gels in response to various endogenous factors, for e.g elevated temperature, pH changes and ions. Such systems can be used in various ways for local or systemic supply of drugs and successfully also as vehicles for drug-induced nano- and micro-particles. In this review we will discuss about various aspects about use of these in situ gels as novel drug delivery systems.

• Polymer(Korea)
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• v.38 no.4
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• pp.434-440
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• 2014

We prepared nanoparticles containing insoluble celecoxib by the method of solid dispersions using a spray dryer to improve solubility of celecoxib. We used PVP K30 and Eudragit EPO as water-soluble carriers for the solid dispersion, and poloxamer 407 as a surfactant. Characterization of celecoxib solid dispersion was performed by scanning electron microscope (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The results of SEM, DSC and XRD demonstrated that celecoxib is amorphous in solid dispersion. The dissolution rate measured in intestinal juice showed that the method of solid dispersion improved celecoxib solubility as compared with a conventional drug (Celebres$^{(R)}$). In conclusion, solid dispersion formulation prepared by a spray dryer would improve the solubility of celecoxib in oral administration.

• Polymer(Korea)
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• v.37 no.2
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• pp.141-147
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• 2013

Poly(lactide-co-glycolic acid) (PLGA) has been widely used in the drug delivery and tissue engineering applications because of its good mechanical strength and biodegradation profile. However, cell attachment to the scaffold is low compared with that on fibrin although cells can be attached to the polymer surface. In this study, PLGA scaffolds were soaked in cells-fibrin suspension and polymerized with dropping fibrinogen-thrombin solution. Cellular proliferation activity was observed in PLGA/fibrin-seeded costal cartilage cells (CC) on 1, 3, and 7 days using the MTT assay and SEM. The effects of fibrin on the extracellular matrix (ECM) formation were evaluated using CC cell-seeded PLGA/fibrin scaffolds. The PLGA/fibrin scaffolds elicited more production of glycosaminoglycan (GAG) and collagen than the PLGA scaffold. In this study, fibrin incorporated PLGA scaffolds were prepared to evaluate the effects of fibrin on the cell attachment and proliferation in vitro and in vivo. In this result, we confirmed that proliferation of cells in PLGA/fibrin scaffolds were better than in PLGA scaffolds. The PLGA/fibrin scaffolds provide suitable environment for growth and proliferation of costal cartilage cells.

• Polymer(Korea)
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• v.37 no.6
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• pp.702-710
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• 2013

Zaltoprofen loaded polyoxalate (POX) microspheres were prepared by an emulsion solvent-evaporation/extraction method like oil-in-water (O/W) for sustained release of zaltoprofen. The influence of several preparation parameters such as fabrication temperature, stirring speed, intensity of the sonication, initial drug ratio, molecular weight ($M_w$) of POX, concentration of POX and concentration of emulsifier has been investigated on the zaltoprofen release profiles. Physicochemical properties and morphology of zaltoprofen loaded POX microspheres were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR). Through the analyzed results, it was demonstrated that the characteristics of the microspheres greatly affected by the prepared condition. The releases behavior of zaltoprofen was investigated for 10 days in vitro. It was confirmed that the release behavior of zaltoprofen can be controlled by the manufacturing factor of solvent-evaporation/extraction method.

• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.43-48
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• 2017

Chemotherapy, radiation therapy, and surgery are major methods to treat cancer. However, current cancer treatments report severe side effects and high recurrences. Recent studies about engineering nanoparticles as a drug carrier suggest possibilities in terms of specific targeting and spatiotemporal release of drugs. While many nanoparticles demonstrate lower toxicity and better targeting results than free drugs, they still need to improve their performance dramatically in terms of targeting accuracy, immune responses, and non-specific accumulation at organs. One possible way to overcome the challenges is to make precisely controlled nanoparticles with respect to size, shape, surface properties, and mechanical stiffness. Here, we demonstrate $500{\times}200nm$ discoidal polymeric nanoconstructs (DPNs) as a drug delivery carrier. DPNs were prepared by using a top-down fabrication method that we previously reported to control shape as well as size. Moreover, DPNs have multiple payloads, poly lactic-co-glycolic acid (PLGA), polyethylene glycol (PEG), lipid-Rhodamine B dye (RhB) and Salinomycin. In this study, we demonstrated a potential of DPNs as a drug carrier to treat cancer.

• Korean Journal of Pharmacognosy
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• v.48 no.3
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• pp.173-178
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• 2017

We investigated the efficacy of single compound of plant extract in coxsackievirus B3 (CVB3) infection. CVB3 is a main cause of Hand-foot-mouth diseases (HFMD) and viral myocarditis in children and adult. Several single compounds of plant extract were purified by HPLC and tested as antiviral drug candidate. Among them, kaempferol was selected to effective anti-enterovirus compound by HeLa cells survival assay. CVB3 infected HeLa cells were treated with kaempferol ($100{\mu}g/ml-100ng/ml$) and their antiviral effect was confirmed. After 16 hours of treatment, HeLa cells were lysed and proteins were extracted for western blot analysis. CVB3 viral capsid protein VP1 production and transcription factor eIF4G-1 cleavage was significantly decreased in $100{\mu}g/ml$ kaempferol treatment. Virus replication was observed by virus RNA amplification. Kaempferol strongly reduced virus positive and negative strand RNA amplification. Moreover, MAPK signal induced by CVB3 infection, pERK and pmTOR, kaempferol treatment significantly inhibited the activity. Plant extract single compound, kaempferol, is a strong candidate to be developed non-toxic anti-enterovirus treatment agent.